148 files changed, 6455 insertions, 2458 deletions

diff --git a/crates/ra_assists/src/assist_context.rs b/crates/ra_assists/src/assist_context.rs
index 5b1a4680b..edd8255f4 100644
--- a/crates/ra_assists/src/assist_context.rs
+++ b/crates/ra_assists/src/assist_context.rs
@@ -1,5 +1,7 @@
 //! See `AssistContext`
 
+use std::mem;
+
 use algo::find_covering_element;
 use hir::Semantics;
 use ra_db::{FileId, FileRange};
@@ -170,13 +172,32 @@ impl Assists {
 
 pub(crate) struct AssistBuilder {
     edit: TextEditBuilder,
-    file: FileId,
+    file_id: FileId,
     is_snippet: bool,
+    edits: Vec<SourceFileEdit>,
 }
 
 impl AssistBuilder {
-    pub(crate) fn new(file: FileId) -> AssistBuilder {
-        AssistBuilder { edit: TextEditBuilder::default(), file, is_snippet: false }
+    pub(crate) fn new(file_id: FileId) -> AssistBuilder {
+        AssistBuilder {
+            edit: TextEditBuilder::default(),
+            file_id,
+            is_snippet: false,
+            edits: Vec::new(),
+        }
+    }
+
+    pub(crate) fn edit_file(&mut self, file_id: FileId) {
+        self.file_id = file_id;
+    }
+
+    fn commit(&mut self) {
+        let edit = mem::take(&mut self.edit).finish();
+        if !edit.is_empty() {
+            let new_edit = SourceFileEdit { file_id: self.file_id, edit };
+            assert!(!self.edits.iter().any(|it| it.file_id == new_edit.file_id));
+            self.edits.push(new_edit);
+        }
     }
 
     /// Remove specified `range` of text.
@@ -234,21 +255,15 @@ impl AssistBuilder {
         algo::diff(&node, &new).into_text_edit(&mut self.edit)
     }
 
-    // FIXME: better API
-    pub(crate) fn set_file(&mut self, assist_file: FileId) {
-        self.file = assist_file;
-    }
-
     // FIXME: kill this API
     /// Get access to the raw `TextEditBuilder`.
     pub(crate) fn text_edit_builder(&mut self) -> &mut TextEditBuilder {
         &mut self.edit
     }
 
-    fn finish(self) -> SourceChange {
-        let edit = self.edit.finish();
-        let source_file_edit = SourceFileEdit { file_id: self.file, edit };
-        let mut res: SourceChange = source_file_edit.into();
+    fn finish(mut self) -> SourceChange {
+        self.commit();
+        let mut res: SourceChange = mem::take(&mut self.edits).into();
         if self.is_snippet {
             res.is_snippet = true;
         }
diff --git a/crates/ra_assists/src/handlers/add_explicit_type.rs b/crates/ra_assists/src/handlers/add_explicit_type.rs
index ab20c6649..90b06a625 100644
--- a/crates/ra_assists/src/handlers/add_explicit_type.rs
+++ b/crates/ra_assists/src/handlers/add_explicit_type.rs
@@ -195,7 +195,7 @@ struct Test<K, T = u8> {
 }
 
 fn main() {
-    let test<|> = Test { t: 23, k: 33 };
+    let test<|> = Test { t: 23u8, k: 33 };
 }"#,
             r#"
 struct Test<K, T = u8> {
@@ -204,7 +204,7 @@ struct Test<K, T = u8> {
 }
 
 fn main() {
-    let test: Test<i32> = Test { t: 23, k: 33 };
+    let test: Test<i32> = Test { t: 23u8, k: 33 };
 }"#,
         );
     }
diff --git a/crates/ra_assists/src/handlers/add_function.rs b/crates/ra_assists/src/handlers/add_function.rs
index 24f931a85..1cfbd75aa 100644
--- a/crates/ra_assists/src/handlers/add_function.rs
+++ b/crates/ra_assists/src/handlers/add_function.rs
@@ -64,7 +64,7 @@ pub(crate) fn add_function(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
     let target = call.syntax().text_range();
     acc.add(AssistId("add_function"), "Add function", target, |builder| {
         let function_template = function_builder.render();
-        builder.set_file(function_template.file);
+        builder.edit_file(function_template.file);
         let new_fn = function_template.to_string(ctx.config.snippet_cap);
         match ctx.config.snippet_cap {
             Some(cap) => builder.insert_snippet(cap, function_template.insert_offset, new_fn),
diff --git a/crates/ra_assists/src/handlers/auto_import.rs b/crates/ra_assists/src/handlers/auto_import.rs
index edf96d50e..5092bf336 100644
--- a/crates/ra_assists/src/handlers/auto_import.rs
+++ b/crates/ra_assists/src/handlers/auto_import.rs
@@ -130,7 +130,7 @@ impl AutoImportAssets {
     fn search_for_imports(&self, db: &RootDatabase) -> BTreeSet<ModPath> {
         let _p = profile("auto_import::search_for_imports");
         let current_crate = self.module_with_name_to_import.krate();
-        ImportsLocator::new(db)
+        ImportsLocator::new(db, current_crate)
             .find_imports(&self.get_search_query())
             .into_iter()
             .filter_map(|candidate| match &self.import_candidate {
@@ -841,4 +841,105 @@ fn main() {
             ",
         )
     }
+
+    #[test]
+    fn dep_import() {
+        check_assist(
+            auto_import,
+            r"
+                    //- /lib.rs crate:dep
+                    pub struct Struct;
+
+                    //- /main.rs crate:main deps:dep
+                    fn main() {
+                        Struct<|>
+                    }",
+            r"use dep::Struct;
+
+fn main() {
+    Struct
+}
+",
+        );
+    }
+
+    #[test]
+    fn whole_segment() {
+        // Tests that only imports whose last segment matches the identifier get suggested.
+        check_assist(
+            auto_import,
+            r"
+                    //- /lib.rs crate:dep
+                    pub mod fmt {
+                        pub trait Display {}
+                    }
+
+                    pub fn panic_fmt() {}
+
+                    //- /main.rs crate:main deps:dep
+                    struct S;
+
+                    impl f<|>mt::Display for S {}",
+            r"use dep::fmt;
+
+struct S;
+impl fmt::Display for S {}
+",
+        );
+    }
+
+    #[test]
+    fn macro_generated() {
+        // Tests that macro-generated items are suggested from external crates.
+        check_assist(
+            auto_import,
+            r"
+                    //- /lib.rs crate:dep
+
+                    macro_rules! mac {
+                        () => {
+                            pub struct Cheese;
+                        };
+                    }
+
+                    mac!();
+
+                    //- /main.rs crate:main deps:dep
+
+                    fn main() {
+                        Cheese<|>;
+                    }",
+            r"use dep::Cheese;
+
+fn main() {
+    Cheese;
+}
+",
+        );
+    }
+
+    #[test]
+    fn casing() {
+        // Tests that differently cased names don't interfere and we only suggest the matching one.
+        check_assist(
+            auto_import,
+            r"
+                    //- /lib.rs crate:dep
+
+                    pub struct FMT;
+                    pub struct fmt;
+
+                    //- /main.rs crate:main deps:dep
+
+                    fn main() {
+                        FMT<|>;
+                    }",
+            r"use dep::FMT;
+
+fn main() {
+    FMT;
+}
+",
+        );
+    }
 }
diff --git a/crates/ra_assists/src/handlers/early_return.rs b/crates/ra_assists/src/handlers/early_return.rs
index 4cc75a7ce..dfade7432 100644
--- a/crates/ra_assists/src/handlers/early_return.rs
+++ b/crates/ra_assists/src/handlers/early_return.rs
@@ -154,7 +154,7 @@ pub(crate) fn convert_to_guarded_return(acc: &mut Assists, ctx: &AssistContext)
             parent_block: &ast::BlockExpr,
             if_expr: &ast::IfExpr,
         ) -> SyntaxNode {
-            let then_block_items = then_block.dedent(IndentLevel::from(1));
+            let then_block_items = then_block.dedent(IndentLevel(1));
             let end_of_then = then_block_items.syntax().last_child_or_token().unwrap();
             let end_of_then =
                 if end_of_then.prev_sibling_or_token().map(|n| n.kind()) == Some(WHITESPACE) {
diff --git a/crates/ra_assists/src/handlers/extract_struct_from_enum_variant.rs b/crates/ra_assists/src/handlers/extract_struct_from_enum_variant.rs
new file mode 100644
index 000000000..44db7917a
--- /dev/null
+++ b/crates/ra_assists/src/handlers/extract_struct_from_enum_variant.rs
@@ -0,0 +1,320 @@
+use hir::{EnumVariant, Module, ModuleDef, Name};
+use ra_db::FileId;
+use ra_fmt::leading_indent;
+use ra_ide_db::{defs::Definition, search::Reference, RootDatabase};
+use ra_syntax::{
+    algo::find_node_at_offset,
+    ast::{self, ArgListOwner, AstNode, NameOwner, VisibilityOwner},
+    SourceFile, SyntaxNode, TextRange, TextSize,
+};
+use rustc_hash::FxHashSet;
+
+use crate::{
+    assist_context::AssistBuilder, utils::insert_use_statement, AssistContext, AssistId, Assists,
+};
+
+// Assist: extract_struct_from_enum_variant
+//
+// Extracts a struct from enum variant.
+//
+// ```
+// enum A { <|>One(u32, u32) }
+// ```
+// ->
+// ```
+// struct One(pub u32, pub u32);
+//
+// enum A { One(One) }
+// ```
+pub(crate) fn extract_struct_from_enum_variant(
+    acc: &mut Assists,
+    ctx: &AssistContext,
+) -> Option<()> {
+    let variant = ctx.find_node_at_offset::<ast::EnumVariant>()?;
+    let field_list = match variant.kind() {
+        ast::StructKind::Tuple(field_list) => field_list,
+        _ => return None,
+    };
+    let variant_name = variant.name()?.to_string();
+    let variant_hir = ctx.sema.to_def(&variant)?;
+    if existing_struct_def(ctx.db, &variant_name, &variant_hir) {
+        return None;
+    }
+    let enum_ast = variant.parent_enum();
+    let visibility = enum_ast.visibility();
+    let enum_hir = ctx.sema.to_def(&enum_ast)?;
+    let variant_hir_name = variant_hir.name(ctx.db);
+    let enum_module_def = ModuleDef::from(enum_hir);
+    let current_module = enum_hir.module(ctx.db);
+    let target = variant.syntax().text_range();
+    acc.add(
+        AssistId("extract_struct_from_enum_variant"),
+        "Extract struct from enum variant",
+        target,
+        |builder| {
+            let definition = Definition::ModuleDef(ModuleDef::EnumVariant(variant_hir));
+            let res = definition.find_usages(&ctx.db, None);
+            let start_offset = variant.parent_enum().syntax().text_range().start();
+            let mut visited_modules_set = FxHashSet::default();
+            visited_modules_set.insert(current_module);
+            for reference in res {
+                let source_file = ctx.sema.parse(reference.file_range.file_id);
+                update_reference(
+                    ctx,
+                    builder,
+                    reference,
+                    &source_file,
+                    &enum_module_def,
+                    &variant_hir_name,
+                    &mut visited_modules_set,
+                );
+            }
+            extract_struct_def(
+                builder,
+                enum_ast.syntax(),
+                &variant_name,
+                &field_list.to_string(),
+                start_offset,
+                ctx.frange.file_id,
+                &visibility,
+            );
+            let list_range = field_list.syntax().text_range();
+            update_variant(builder, &variant_name, ctx.frange.file_id, list_range);
+        },
+    )
+}
+
+fn existing_struct_def(db: &RootDatabase, variant_name: &str, variant: &EnumVariant) -> bool {
+    variant
+        .parent_enum(db)
+        .module(db)
+        .scope(db, None)
+        .into_iter()
+        .any(|(name, _)| name.to_string() == variant_name.to_string())
+}
+
+fn insert_import(
+    ctx: &AssistContext,
+    builder: &mut AssistBuilder,
+    path: &ast::PathExpr,
+    module: &Module,
+    enum_module_def: &ModuleDef,
+    variant_hir_name: &Name,
+) -> Option<()> {
+    let db = ctx.db;
+    let mod_path = module.find_use_path(db, enum_module_def.clone());
+    if let Some(mut mod_path) = mod_path {
+        mod_path.segments.pop();
+        mod_path.segments.push(variant_hir_name.clone());
+        insert_use_statement(path.syntax(), &mod_path, ctx, builder.text_edit_builder());
+    }
+    Some(())
+}
+
+fn extract_struct_def(
+    builder: &mut AssistBuilder,
+    enum_ast: &SyntaxNode,
+    variant_name: &str,
+    variant_list: &str,
+    start_offset: TextSize,
+    file_id: FileId,
+    visibility: &Option<ast::Visibility>,
+) -> Option<()> {
+    let visibility_string = if let Some(visibility) = visibility {
+        format!("{} ", visibility.to_string())
+    } else {
+        "".to_string()
+    };
+    let indent = if let Some(indent) = leading_indent(enum_ast) {
+        indent.to_string()
+    } else {
+        "".to_string()
+    };
+    let struct_def = format!(
+        r#"{}struct {}{};
+
+{}"#,
+        visibility_string,
+        variant_name,
+        list_with_visibility(variant_list),
+        indent
+    );
+    builder.edit_file(file_id);
+    builder.insert(start_offset, struct_def);
+    Some(())
+}
+
+fn update_variant(
+    builder: &mut AssistBuilder,
+    variant_name: &str,
+    file_id: FileId,
+    list_range: TextRange,
+) -> Option<()> {
+    let inside_variant_range = TextRange::new(
+        list_range.start().checked_add(TextSize::from(1))?,
+        list_range.end().checked_sub(TextSize::from(1))?,
+    );
+    builder.edit_file(file_id);
+    builder.replace(inside_variant_range, variant_name);
+    Some(())
+}
+
+fn update_reference(
+    ctx: &AssistContext,
+    builder: &mut AssistBuilder,
+    reference: Reference,
+    source_file: &SourceFile,
+    enum_module_def: &ModuleDef,
+    variant_hir_name: &Name,
+    visited_modules_set: &mut FxHashSet<Module>,
+) -> Option<()> {
+    let path_expr: ast::PathExpr = find_node_at_offset::<ast::PathExpr>(
+        source_file.syntax(),
+        reference.file_range.range.start(),
+    )?;
+    let call = path_expr.syntax().parent().and_then(ast::CallExpr::cast)?;
+    let list = call.arg_list()?;
+    let segment = path_expr.path()?.segment()?;
+    let module = ctx.sema.scope(&path_expr.syntax()).module()?;
+    let list_range = list.syntax().text_range();
+    let inside_list_range = TextRange::new(
+        list_range.start().checked_add(TextSize::from(1))?,
+        list_range.end().checked_sub(TextSize::from(1))?,
+    );
+    builder.edit_file(reference.file_range.file_id);
+    if !visited_modules_set.contains(&module) {
+        if insert_import(ctx, builder, &path_expr, &module, enum_module_def, variant_hir_name)
+            .is_some()
+        {
+            visited_modules_set.insert(module);
+        }
+    }
+    builder.replace(inside_list_range, format!("{}{}", segment, list));
+    Some(())
+}
+
+fn list_with_visibility(list: &str) -> String {
+    list.split(',')
+        .map(|part| {
+            let index = if part.chars().next().unwrap() == '(' { 1usize } else { 0 };
+            let mut mod_part = part.trim().to_string();
+            mod_part.insert_str(index, "pub ");
+            mod_part
+        })
+        .collect::<Vec<String>>()
+        .join(", ")
+}
+
+#[cfg(test)]
+mod tests {
+
+    use crate::{
+        tests::{check_assist, check_assist_not_applicable},
+        utils::FamousDefs,
+    };
+
+    use super::*;
+
+    #[test]
+    fn test_extract_struct_several_fields() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            "enum A { <|>One(u32, u32) }",
+            r#"struct One(pub u32, pub u32);
+
+enum A { One(One) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_struct_one_field() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            "enum A { <|>One(u32) }",
+            r#"struct One(pub u32);
+
+enum A { One(One) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_struct_pub_visibility() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            "pub enum A { <|>One(u32, u32) }",
+            r#"pub struct One(pub u32, pub u32);
+
+pub enum A { One(One) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_struct_with_complex_imports() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            r#"mod my_mod {
+    fn another_fn() {
+        let m = my_other_mod::MyEnum::MyField(1, 1);
+    }
+
+    pub mod my_other_mod {
+        fn another_fn() {
+            let m = MyEnum::MyField(1, 1);
+        }
+
+        pub enum MyEnum {
+            <|>MyField(u8, u8),
+        }
+    }
+}
+
+fn another_fn() {
+    let m = my_mod::my_other_mod::MyEnum::MyField(1, 1);
+}"#,
+            r#"use my_mod::my_other_mod::MyField;
+
+mod my_mod {
+    use my_other_mod::MyField;
+
+    fn another_fn() {
+        let m = my_other_mod::MyEnum::MyField(MyField(1, 1));
+    }
+
+    pub mod my_other_mod {
+        fn another_fn() {
+            let m = MyEnum::MyField(MyField(1, 1));
+        }
+
+        pub struct MyField(pub u8, pub u8);
+
+        pub enum MyEnum {
+            MyField(MyField),
+        }
+    }
+}
+
+fn another_fn() {
+    let m = my_mod::my_other_mod::MyEnum::MyField(MyField(1, 1));
+}"#,
+        );
+    }
+
+    fn check_not_applicable(ra_fixture: &str) {
+        let fixture =
+            format!("//- main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
+        check_assist_not_applicable(extract_struct_from_enum_variant, &fixture)
+    }
+
+    #[test]
+    fn test_extract_enum_not_applicable_for_element_with_no_fields() {
+        check_not_applicable("enum A { <|>One }");
+    }
+
+    #[test]
+    fn test_extract_enum_not_applicable_if_struct_exists() {
+        check_not_applicable(
+            r#"struct One;
+        enum A { <|>One(u8) }"#,
+        );
+    }
+}
diff --git a/crates/ra_assists/src/handlers/fix_visibility.rs b/crates/ra_assists/src/handlers/fix_visibility.rs
index 9ec42f568..531b3560f 100644
--- a/crates/ra_assists/src/handlers/fix_visibility.rs
+++ b/crates/ra_assists/src/handlers/fix_visibility.rs
@@ -63,7 +63,7 @@ fn add_vis_to_referenced_module_def(acc: &mut Assists, ctx: &AssistContext) -> O
     };
 
     acc.add(AssistId("fix_visibility"), assist_label, target, |builder| {
-        builder.set_file(target_file);
+        builder.edit_file(target_file);
         match ctx.config.snippet_cap {
             Some(cap) => builder.insert_snippet(cap, offset, format!("$0{} ", missing_visibility)),
             None => builder.insert(offset, format!("{} ", missing_visibility)),
@@ -106,7 +106,7 @@ fn add_vis_to_referenced_record_field(acc: &mut Assists, ctx: &AssistContext) ->
         format!("Change visibility of {}.{} to {}", parent_name, target_name, missing_visibility);
 
     acc.add(AssistId("fix_visibility"), assist_label, target, |builder| {
-        builder.set_file(target_file);
+        builder.edit_file(target_file);
         match ctx.config.snippet_cap {
             Some(cap) => builder.insert_snippet(cap, offset, format!("$0{} ", missing_visibility)),
             None => builder.insert(offset, format!("{} ", missing_visibility)),
diff --git a/crates/ra_assists/src/handlers/introduce_named_lifetime.rs b/crates/ra_assists/src/handlers/introduce_named_lifetime.rs
index beb5b7366..28fcbc9ba 100644
--- a/crates/ra_assists/src/handlers/introduce_named_lifetime.rs
+++ b/crates/ra_assists/src/handlers/introduce_named_lifetime.rs
@@ -41,8 +41,6 @@ pub(crate) fn introduce_named_lifetime(acc: &mut Assists, ctx: &AssistContext) -
     if let Some(fn_def) = lifetime_token.ancestors().find_map(ast::FnDef::cast) {
         generate_fn_def_assist(acc, &fn_def, lifetime_token.text_range())
     } else if let Some(impl_def) = lifetime_token.ancestors().find_map(ast::ImplDef::cast) {
-        // only allow naming the last anonymous lifetime
-        lifetime_token.next_token().filter(|tok| tok.kind() == SyntaxKind::R_ANGLE)?;
         generate_impl_def_assist(acc, &impl_def, lifetime_token.text_range())
     } else {
         None
@@ -191,6 +189,23 @@ mod tests {
     }
 
     #[test]
+    fn test_impl_with_other_type_param() {
+        check_assist(
+            introduce_named_lifetime,
+            "impl<I> fmt::Display for SepByBuilder<'_<|>, I>
+        where
+            I: Iterator,
+            I::Item: fmt::Display,
+        {",
+            "impl<I, 'a> fmt::Display for SepByBuilder<'a, I>
+        where
+            I: Iterator,
+            I::Item: fmt::Display,
+        {",
+        )
+    }
+
+    #[test]
     fn test_example_case_cursor_before_tick() {
         check_assist(
             introduce_named_lifetime,
diff --git a/crates/ra_assists/src/handlers/replace_if_let_with_match.rs b/crates/ra_assists/src/handlers/replace_if_let_with_match.rs
index e016f51c3..dfcd787de 100644
--- a/crates/ra_assists/src/handlers/replace_if_let_with_match.rs
+++ b/crates/ra_assists/src/handlers/replace_if_let_with_match.rs
@@ -51,6 +51,7 @@ pub(crate) fn replace_if_let_with_match(acc: &mut Assists, ctx: &AssistContext)
     acc.add(AssistId("replace_if_let_with_match"), "Replace with match", target, move |edit| {
         let match_expr = {
             let then_arm = {
+                let then_block = then_block.reset_indent().indent(IndentLevel(1));
                 let then_expr = unwrap_trivial_block(then_block);
                 make::match_arm(vec![pat.clone()], then_expr)
             };
@@ -64,8 +65,8 @@ pub(crate) fn replace_if_let_with_match(acc: &mut Assists, ctx: &AssistContext)
                 let else_expr = unwrap_trivial_block(else_block);
                 make::match_arm(vec![pattern], else_expr)
             };
-            make::expr_match(expr, make::match_arm_list(vec![then_arm, else_arm]))
-                .indent(IndentLevel::from_node(if_expr.syntax()))
+            let match_expr = make::expr_match(expr, make::match_arm_list(vec![then_arm, else_arm]));
+            match_expr.indent(IndentLevel::from_node(if_expr.syntax()))
         };
 
         edit.replace_ast::<ast::Expr>(if_expr.into(), match_expr);
@@ -213,4 +214,36 @@ fn foo(x: Result<i32, ()>) {
            "#,
         );
     }
+
+    #[test]
+    fn nested_indent() {
+        check_assist(
+            replace_if_let_with_match,
+            r#"
+fn main() {
+    if true {
+        <|>if let Ok(rel_path) = path.strip_prefix(root_path) {
+            let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+            Some((*id, rel_path))
+        } else {
+            None
+        }
+    }
+}
+"#,
+            r#"
+fn main() {
+    if true {
+        match path.strip_prefix(root_path) {
+            Ok(rel_path) => {
+                let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+                Some((*id, rel_path))
+            }
+            _ => None,
+        }
+    }
+}
+"#,
+        )
+    }
 }
diff --git a/crates/ra_assists/src/handlers/unwrap_block.rs b/crates/ra_assists/src/handlers/unwrap_block.rs
index 8440c7d0f..1fb13f481 100644
--- a/crates/ra_assists/src/handlers/unwrap_block.rs
+++ b/crates/ra_assists/src/handlers/unwrap_block.rs
@@ -1,7 +1,10 @@
 use ra_fmt::unwrap_trivial_block;
 use ra_syntax::{
-    ast::{self, ElseBranch, Expr, LoopBodyOwner},
-    match_ast, AstNode, TextRange, T,
+    ast::{
+        self,
+        edit::{AstNodeEdit, IndentLevel},
+    },
+    AstNode, TextRange, T,
 };
 
 use crate::{AssistContext, AssistId, Assists};
@@ -24,94 +27,73 @@ use crate::{AssistContext, AssistId, Assists};
 // }
 // ```
 pub(crate) fn unwrap_block(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
-    let l_curly_token = ctx.find_token_at_offset(T!['{'])?;
-    let block = ast::BlockExpr::cast(l_curly_token.parent())?;
-    let parent = block.syntax().parent()?;
     let assist_id = AssistId("unwrap_block");
     let assist_label = "Unwrap block";
 
-    let (expr, expr_to_unwrap) = match_ast! {
-        match parent {
-            ast::ForExpr(for_expr) => {
-                let block_expr = for_expr.loop_body()?;
-                let expr_to_unwrap = extract_expr(ctx.frange.range, block_expr)?;
-                (ast::Expr::ForExpr(for_expr), expr_to_unwrap)
-            },
-            ast::WhileExpr(while_expr) => {
-                let block_expr = while_expr.loop_body()?;
-                let expr_to_unwrap = extract_expr(ctx.frange.range, block_expr)?;
-                (ast::Expr::WhileExpr(while_expr), expr_to_unwrap)
-            },
-            ast::LoopExpr(loop_expr) => {
-                let block_expr = loop_expr.loop_body()?;
-                let expr_to_unwrap = extract_expr(ctx.frange.range, block_expr)?;
-                (ast::Expr::LoopExpr(loop_expr), expr_to_unwrap)
-            },
-            ast::IfExpr(if_expr) => {
-                let mut resp = None;
-
-                let then_branch = if_expr.then_branch()?;
-                if then_branch.l_curly_token()?.text_range().contains_range(ctx.frange.range) {
-                    if let Some(ancestor) = if_expr.syntax().parent().and_then(ast::IfExpr::cast) {
-                        // For `else if` blocks
-                        let ancestor_then_branch = ancestor.then_branch()?;
-                        let l_curly_token = then_branch.l_curly_token()?;
-
-                        let target = then_branch.syntax().text_range();
-                        return acc.add(assist_id, assist_label, target, |edit| {
-                            let range_to_del_else_if = TextRange::new(ancestor_then_branch.syntax().text_range().end(), l_curly_token.text_range().start());
-                            let range_to_del_rest = TextRange::new(then_branch.syntax().text_range().end(), if_expr.syntax().text_range().end());
-
-                            edit.delete(range_to_del_rest);
-                            edit.delete(range_to_del_else_if);
-                            edit.replace(target, update_expr_string(then_branch.to_string(), &[' ', '{']));
-                        });
-                    } else {
-                        resp = Some((ast::Expr::IfExpr(if_expr.clone()), Expr::BlockExpr(then_branch)));
-                    }
-                } else if let Some(else_branch) = if_expr.else_branch() {
-                    match else_branch {
-                        ElseBranch::Block(else_block) => {
-                            let l_curly_token = else_block.l_curly_token()?;
-                            if l_curly_token.text_range().contains_range(ctx.frange.range) {
-                                let target = else_block.syntax().text_range();
-                                return acc.add(assist_id, assist_label, target, |edit| {
-                                    let range_to_del = TextRange::new(then_branch.syntax().text_range().end(), l_curly_token.text_range().start());
-
-                                    edit.delete(range_to_del);
-                                    edit.replace(target, update_expr_string(else_block.to_string(), &[' ', '{']));
-                                });
-                            }
-                        },
-                        ElseBranch::IfExpr(_) => {},
-                    }
-                }
+    let l_curly_token = ctx.find_token_at_offset(T!['{'])?;
+    let mut block = ast::BlockExpr::cast(l_curly_token.parent())?;
+    let mut parent = block.syntax().parent()?;
+    if ast::MatchArm::can_cast(parent.kind()) {
+        parent = parent.ancestors().find(|it| ast::MatchExpr::can_cast(it.kind()))?
+    }
 
-                resp?
-            },
-            _ => return None,
+    let parent = ast::Expr::cast(parent)?;
+
+    match parent.clone() {
+        ast::Expr::ForExpr(_) | ast::Expr::WhileExpr(_) | ast::Expr::LoopExpr(_) => (),
+        ast::Expr::MatchExpr(_) => block = block.dedent(IndentLevel(1)),
+        ast::Expr::IfExpr(if_expr) => {
+            let then_branch = if_expr.then_branch()?;
+            if then_branch == block {
+                if let Some(ancestor) = if_expr.syntax().parent().and_then(ast::IfExpr::cast) {
+                    // For `else if` blocks
+                    let ancestor_then_branch = ancestor.then_branch()?;
+
+                    let target = then_branch.syntax().text_range();
+                    return acc.add(assist_id, assist_label, target, |edit| {
+                        let range_to_del_else_if = TextRange::new(
+                            ancestor_then_branch.syntax().text_range().end(),
+                            l_curly_token.text_range().start(),
+                        );
+                        let range_to_del_rest = TextRange::new(
+                            then_branch.syntax().text_range().end(),
+                            if_expr.syntax().text_range().end(),
+                        );
+
+                        edit.delete(range_to_del_rest);
+                        edit.delete(range_to_del_else_if);
+                        edit.replace(
+                            target,
+                            update_expr_string(then_branch.to_string(), &[' ', '{']),
+                        );
+                    });
+                }
+            } else {
+                let target = block.syntax().text_range();
+                return acc.add(assist_id, assist_label, target, |edit| {
+                    let range_to_del = TextRange::new(
+                        then_branch.syntax().text_range().end(),
+                        l_curly_token.text_range().start(),
+                    );
+
+                    edit.delete(range_to_del);
+                    edit.replace(target, update_expr_string(block.to_string(), &[' ', '{']));
+                });
+            }
         }
+        _ => return None,
     };
 
-    let target = expr_to_unwrap.syntax().text_range();
-    acc.add(assist_id, assist_label, target, |edit| {
-        edit.replace(
-            expr.syntax().text_range(),
-            update_expr_string(expr_to_unwrap.to_string(), &[' ', '{', '\n']),
+    let unwrapped = unwrap_trivial_block(block);
+    let target = unwrapped.syntax().text_range();
+    acc.add(assist_id, assist_label, target, |builder| {
+        builder.replace(
+            parent.syntax().text_range(),
+            update_expr_string(unwrapped.to_string(), &[' ', '{', '\n']),
         );
     })
 }
 
-fn extract_expr(cursor_range: TextRange, block: ast::BlockExpr) -> Option<ast::Expr> {
-    let cursor_in_range = block.l_curly_token()?.text_range().contains_range(cursor_range);
-
-    if cursor_in_range {
-        Some(unwrap_trivial_block(block))
-    } else {
-        None
-    }
-}
-
 fn update_expr_string(expr_str: String, trim_start_pat: &[char]) -> String {
     let expr_string = expr_str.trim_start_matches(trim_start_pat);
     let mut expr_string_lines: Vec<&str> = expr_string.lines().collect();
@@ -490,6 +472,30 @@ mod tests {
     }
 
     #[test]
+    fn unwrap_match_arm() {
+        check_assist(
+            unwrap_block,
+            r#"
+fn main() {
+    match rel_path {
+        Ok(rel_path) => {<|>
+            let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+            Some((*id, rel_path))
+        }
+        Err(_) => None,
+    }
+}
+"#,
+            r#"
+fn main() {
+    let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+    Some((*id, rel_path))
+}
+"#,
+        );
+    }
+
+    #[test]
     fn simple_if_in_while_bad_cursor_position() {
         check_assist_not_applicable(
             unwrap_block,
diff --git a/crates/ra_assists/src/lib.rs b/crates/ra_assists/src/lib.rs
index fb5d59a87..185428bd5 100644
--- a/crates/ra_assists/src/lib.rs
+++ b/crates/ra_assists/src/lib.rs
@@ -115,6 +115,7 @@ mod handlers {
     mod change_return_type_to_result;
     mod change_visibility;
     mod early_return;
+    mod extract_struct_from_enum_variant;
     mod fill_match_arms;
     mod fix_visibility;
     mod flip_binexpr;
@@ -155,6 +156,7 @@ mod handlers {
             change_return_type_to_result::change_return_type_to_result,
             change_visibility::change_visibility,
             early_return::convert_to_guarded_return,
+            extract_struct_from_enum_variant::extract_struct_from_enum_variant,
             fill_match_arms::fill_match_arms,
             fix_visibility::fix_visibility,
             flip_binexpr::flip_binexpr,
diff --git a/crates/ra_assists/src/tests/generated.rs b/crates/ra_assists/src/tests/generated.rs
index d17504529..40a223727 100644
--- a/crates/ra_assists/src/tests/generated.rs
+++ b/crates/ra_assists/src/tests/generated.rs
@@ -338,6 +338,21 @@ fn main() {
 }
 
 #[test]
+fn doctest_extract_struct_from_enum_variant() {
+    check_doc_test(
+        "extract_struct_from_enum_variant",
+        r#####"
+enum A { <|>One(u32, u32) }
+"#####,
+        r#####"
+struct One(pub u32, pub u32);
+
+enum A { One(One) }
+"#####,
+    )
+}
+
+#[test]
 fn doctest_fill_match_arms() {
     check_doc_test(
         "fill_match_arms",
diff --git a/crates/ra_db/src/input.rs b/crates/ra_db/src/input.rs
index 4d2d3b48a..bf26048f2 100644
--- a/crates/ra_db/src/input.rs
+++ b/crates/ra_db/src/input.rs
@@ -15,12 +15,10 @@ use std::{
 
 use ra_cfg::CfgOptions;
 use ra_syntax::SmolStr;
-use rustc_hash::FxHashMap;
-use rustc_hash::FxHashSet;
+use ra_tt::TokenExpander;
+use rustc_hash::{FxHashMap, FxHashSet};
 
 use crate::{RelativePath, RelativePathBuf};
-use fmt::Display;
-use ra_tt::TokenExpander;
 
 /// `FileId` is an integer which uniquely identifies a file. File paths are
 /// messy and system-dependent, so most of the code should work directly with
@@ -111,7 +109,7 @@ impl CrateName {
     }
 }
 
-impl Display for CrateName {
+impl fmt::Display for CrateName {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{}", self.0)
     }
@@ -337,15 +335,11 @@ impl Env {
 }
 
 impl ExternSource {
-    pub fn extern_path(&self, path: impl AsRef<Path>) -> Option<(ExternSourceId, RelativePathBuf)> {
-        let path = path.as_ref();
+    pub fn extern_path(&self, path: &Path) -> Option<(ExternSourceId, RelativePathBuf)> {
         self.extern_paths.iter().find_map(|(root_path, id)| {
-            if let Ok(rel_path) = path.strip_prefix(root_path) {
-                let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
-                Some((*id, rel_path))
-            } else {
-                None
-            }
+            let rel_path = path.strip_prefix(root_path).ok()?;
+            let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+            Some((*id, rel_path))
         })
     }
 
diff --git a/crates/ra_db/src/lib.rs b/crates/ra_db/src/lib.rs
index fd4280de2..80ddb6058 100644
--- a/crates/ra_db/src/lib.rs
+++ b/crates/ra_db/src/lib.rs
@@ -7,12 +7,13 @@ use std::{panic, sync::Arc};
 
 use ra_prof::profile;
 use ra_syntax::{ast, Parse, SourceFile, TextRange, TextSize};
+use rustc_hash::FxHashSet;
 
 pub use crate::{
     cancellation::Canceled,
     input::{
-        CrateGraph, CrateId, CrateName, Dependency, Edition, Env, ExternSource, ExternSourceId,
-        FileId, ProcMacroId, SourceRoot, SourceRootId,
+        CrateData, CrateGraph, CrateId, CrateName, Dependency, Edition, Env, ExternSource,
+        ExternSourceId, FileId, ProcMacroId, SourceRoot, SourceRootId,
     },
 };
 pub use relative_path::{RelativePath, RelativePathBuf};
@@ -89,15 +90,13 @@ pub const DEFAULT_LRU_CAP: usize = 128;
 pub trait FileLoader {
     /// Text of the file.
     fn file_text(&self, file_id: FileId) -> Arc<String>;
-    fn resolve_relative_path(&self, anchor: FileId, relative_path: &RelativePath)
-        -> Option<FileId>;
-    fn relevant_crates(&self, file_id: FileId) -> Arc<Vec<CrateId>>;
-
-    fn resolve_extern_path(
-        &self,
-        extern_id: ExternSourceId,
-        relative_path: &RelativePath,
-    ) -> Option<FileId>;
+    /// Note that we intentionally accept a `&str` and not a `&Path` here. This
+    /// method exists to handle `#[path = "/some/path.rs"] mod foo;` and such,
+    /// so the input is guaranteed to be utf-8 string. We might introduce
+    /// `struct StrPath(str)` for clarity some day, but it's a bit messy, so we
+    /// get by with a `&str` for the time being.
+    fn resolve_path(&self, anchor: FileId, path: &str) -> Option<FileId>;
+    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>>;
 }
 
 /// Database which stores all significant input facts: source code and project
@@ -135,16 +134,21 @@ pub trait SourceDatabaseExt: SourceDatabase {
     #[salsa::input]
     fn source_root(&self, id: SourceRootId) -> Arc<SourceRoot>;
 
-    fn source_root_crates(&self, id: SourceRootId) -> Arc<Vec<CrateId>>;
+    fn source_root_crates(&self, id: SourceRootId) -> Arc<FxHashSet<CrateId>>;
 }
 
 fn source_root_crates(
     db: &(impl SourceDatabaseExt + SourceDatabase),
     id: SourceRootId,
-) -> Arc<Vec<CrateId>> {
-    let root = db.source_root(id);
+) -> Arc<FxHashSet<CrateId>> {
     let graph = db.crate_graph();
-    let res = root.walk().filter_map(|it| graph.crate_id_for_crate_root(it)).collect::<Vec<_>>();
+    let res = graph
+        .iter()
+        .filter(|&krate| {
+            let root_file = graph[krate].root_file_id;
+            db.file_source_root(root_file) == id
+        })
+        .collect::<FxHashSet<_>>();
     Arc::new(res)
 }
 
@@ -155,33 +159,30 @@ impl<T: SourceDatabaseExt> FileLoader for FileLoaderDelegate<&'_ T> {
     fn file_text(&self, file_id: FileId) -> Arc<String> {
         SourceDatabaseExt::file_text(self.0, file_id)
     }
-    fn resolve_relative_path(
-        &self,
-        anchor: FileId,
-        relative_path: &RelativePath,
-    ) -> Option<FileId> {
-        let path = {
-            let mut path = self.0.file_relative_path(anchor);
-            assert!(path.pop());
-            path.push(relative_path);
-            path.normalize()
-        };
-        let source_root = self.0.file_source_root(anchor);
-        let source_root = self.0.source_root(source_root);
-        source_root.file_by_relative_path(&path)
+    fn resolve_path(&self, anchor: FileId, path: &str) -> Option<FileId> {
+        // FIXME: this *somehow* should be platform agnostic...
+        if std::path::Path::new(path).is_absolute() {
+            let krate = *self.relevant_crates(anchor).iter().next()?;
+            let (extern_source_id, relative_file) =
+                self.0.crate_graph()[krate].extern_source.extern_path(path.as_ref())?;
+
+            let source_root = self.0.source_root(SourceRootId(extern_source_id.0));
+            source_root.file_by_relative_path(&relative_file)
+        } else {
+            let rel_path = {
+                let mut rel_path = self.0.file_relative_path(anchor);
+                assert!(rel_path.pop());
+                rel_path.push(path);
+                rel_path.normalize()
+            };
+            let source_root = self.0.file_source_root(anchor);
+            let source_root = self.0.source_root(source_root);
+            source_root.file_by_relative_path(&rel_path)
+        }
     }
 
-    fn relevant_crates(&self, file_id: FileId) -> Arc<Vec<CrateId>> {
+    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>> {
         let source_root = self.0.file_source_root(file_id);
         self.0.source_root_crates(source_root)
     }
-
-    fn resolve_extern_path(
-        &self,
-        extern_id: ExternSourceId,
-        relative_path: &RelativePath,
-    ) -> Option<FileId> {
-        let source_root = self.0.source_root(SourceRootId(extern_id.0));
-        source_root.file_by_relative_path(&relative_path)
-    }
 }
diff --git a/crates/ra_flycheck/src/lib.rs b/crates/ra_flycheck/src/lib.rs
index 041e38a9f..6c4170529 100644
--- a/crates/ra_flycheck/src/lib.rs
+++ b/crates/ra_flycheck/src/lib.rs
@@ -18,8 +18,17 @@ pub use cargo_metadata::diagnostic::{
 
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub enum FlycheckConfig {
-    CargoCommand { command: String, all_targets: bool, all_features: bool, extra_args: Vec<String> },
-    CustomCommand { command: String, args: Vec<String> },
+    CargoCommand {
+        command: String,
+        all_targets: bool,
+        all_features: bool,
+        features: Vec<String>,
+        extra_args: Vec<String>,
+    },
+    CustomCommand {
+        command: String,
+        args: Vec<String>,
+    },
 }
 
 /// Flycheck wraps the shared state and communication machinery used for
@@ -188,7 +197,13 @@ impl FlycheckThread {
         self.check_process = None;
 
         let mut cmd = match &self.config {
-            FlycheckConfig::CargoCommand { command, all_targets, all_features, extra_args } => {
+            FlycheckConfig::CargoCommand {
+                command,
+                all_targets,
+                all_features,
+                extra_args,
+                features,
+            } => {
                 let mut cmd = Command::new(ra_toolchain::cargo());
                 cmd.arg(command);
                 cmd.args(&["--workspace", "--message-format=json", "--manifest-path"])
@@ -198,6 +213,9 @@ impl FlycheckThread {
                 }
                 if *all_features {
                     cmd.arg("--all-features");
+                } else if !features.is_empty() {
+                    cmd.arg("--features");
+                    cmd.arg(features.join(" "));
                 }
                 cmd.args(extra_args);
                 cmd
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index e40aeffbc..1a9f6cc76 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -9,6 +9,7 @@ use hir_def::{
     builtin_type::BuiltinType,
     docs::Documentation,
     expr::{BindingAnnotation, Pat, PatId},
+    import_map,
     per_ns::PerNs,
     resolver::{HasResolver, Resolver},
     type_ref::{Mutability, TypeRef},
@@ -98,6 +99,23 @@ impl Crate {
         db.crate_graph()[self.id].display_name.as_ref().cloned()
     }
 
+    pub fn query_external_importables(
+        self,
+        db: &dyn DefDatabase,
+        query: &str,
+    ) -> impl Iterator<Item = Either<ModuleDef, MacroDef>> {
+        import_map::search_dependencies(
+            db,
+            self.into(),
+            import_map::Query::new(query).anchor_end().case_sensitive().limit(40),
+        )
+        .into_iter()
+        .map(|item| match item {
+            ItemInNs::Types(mod_id) | ItemInNs::Values(mod_id) => Either::Left(mod_id.into()),
+            ItemInNs::Macros(mac_id) => Either::Right(mac_id.into()),
+        })
+    }
+
     pub fn all(db: &dyn HirDatabase) -> Vec<Crate> {
         db.crate_graph().iter().map(|id| Crate { id }).collect()
     }
@@ -637,6 +655,10 @@ impl Function {
         db.function_data(self.id).params.clone()
     }
 
+    pub fn is_unsafe(self, db: &dyn HirDatabase) -> bool {
+        db.function_data(self.id).is_unsafe
+    }
+
     pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
         let _p = profile("Function::diagnostics");
         let infer = db.infer(self.id.into());
@@ -1190,6 +1212,10 @@ impl Type {
         )
     }
 
+    pub fn is_raw_ptr(&self) -> bool {
+        matches!(&self.ty.value, Ty::Apply(ApplicationTy { ctor: TypeCtor::RawPtr(..), .. }))
+    }
+
     pub fn contains_unknown(&self) -> bool {
         return go(&self.ty.value);
 
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index ec931b34f..b6b665de1 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -3,11 +3,11 @@
 pub use hir_def::db::{
     AttrsQuery, BodyQuery, BodyWithSourceMapQuery, ConstDataQuery, CrateDefMapQueryQuery,
     CrateLangItemsQuery, DefDatabase, DefDatabaseStorage, DocumentationQuery, EnumDataQuery,
-    ExprScopesQuery, FunctionDataQuery, GenericParamsQuery, ImplDataQuery, InternConstQuery,
-    InternDatabase, InternDatabaseStorage, InternEnumQuery, InternFunctionQuery, InternImplQuery,
-    InternStaticQuery, InternStructQuery, InternTraitQuery, InternTypeAliasQuery, InternUnionQuery,
-    LangItemQuery, ModuleLangItemsQuery, RawItemsQuery, StaticDataQuery, StructDataQuery,
-    TraitDataQuery, TypeAliasDataQuery, UnionDataQuery,
+    ExprScopesQuery, FunctionDataQuery, GenericParamsQuery, ImplDataQuery, ImportMapQuery,
+    InternConstQuery, InternDatabase, InternDatabaseStorage, InternEnumQuery, InternFunctionQuery,
+    InternImplQuery, InternStaticQuery, InternStructQuery, InternTraitQuery, InternTypeAliasQuery,
+    InternUnionQuery, LangItemQuery, ModuleLangItemsQuery, RawItemsQuery, StaticDataQuery,
+    StructDataQuery, TraitDataQuery, TypeAliasDataQuery, UnionDataQuery,
 };
 pub use hir_expand::db::{
     AstDatabase, AstDatabaseStorage, AstIdMapQuery, InternEagerExpansionQuery, InternMacroQuery,
@@ -18,8 +18,8 @@ pub use hir_ty::db::{
     GenericDefaultsQuery, GenericPredicatesForParamQuery, GenericPredicatesQuery, HirDatabase,
     HirDatabaseStorage, ImplDatumQuery, ImplSelfTyQuery, ImplTraitQuery, ImplsForTraitQuery,
     ImplsInCrateQuery, InferQueryQuery, InternAssocTyValueQuery, InternChalkImplQuery,
-    InternTypeCtorQuery, InternTypeParamIdQuery, StructDatumQuery, TraitDatumQuery,
-    TraitSolveQuery, TyQuery, ValueTyQuery,
+    InternTypeCtorQuery, InternTypeParamIdQuery, ReturnTypeImplTraitsQuery, StructDatumQuery,
+    TraitDatumQuery, TraitSolveQuery, TyQuery, ValueTyQuery,
 };
 
 #[test]
diff --git a/crates/ra_hir/src/semantics.rs b/crates/ra_hir/src/semantics.rs
index 7c1f79f27..a232a5856 100644
--- a/crates/ra_hir/src/semantics.rs
+++ b/crates/ra_hir/src/semantics.rs
@@ -122,8 +122,9 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         let macro_call =
             self.find_file(actual_macro_call.syntax().clone()).with_value(actual_macro_call);
         let sa = self.analyze2(macro_call.map(|it| it.syntax()), None);
+        let krate = sa.resolver.krate()?;
         let macro_call_id = macro_call
-            .as_call_id(self.db, |path| sa.resolver.resolve_path_as_macro(self.db, &path))?;
+            .as_call_id(self.db, krate, |path| sa.resolver.resolve_path_as_macro(self.db, &path))?;
         hir_expand::db::expand_hypothetical(self.db, macro_call_id, hypothetical_args, token_to_map)
     }
 
diff --git a/crates/ra_hir/src/source_analyzer.rs b/crates/ra_hir/src/source_analyzer.rs
index 4b509f07c..7c6bbea13 100644
--- a/crates/ra_hir/src/source_analyzer.rs
+++ b/crates/ra_hir/src/source_analyzer.rs
@@ -307,7 +307,8 @@ impl SourceAnalyzer {
         db: &dyn HirDatabase,
         macro_call: InFile<&ast::MacroCall>,
     ) -> Option<HirFileId> {
-        let macro_call_id = macro_call.as_call_id(db.upcast(), |path| {
+        let krate = self.resolver.krate()?;
+        let macro_call_id = macro_call.as_call_id(db.upcast(), krate, |path| {
             self.resolver.resolve_path_as_macro(db.upcast(), &path)
         })?;
         Some(macro_call_id.as_file())
diff --git a/crates/ra_hir_def/Cargo.toml b/crates/ra_hir_def/Cargo.toml
index b85358308..ef1f65ee0 100644
--- a/crates/ra_hir_def/Cargo.toml
+++ b/crates/ra_hir_def/Cargo.toml
@@ -14,6 +14,9 @@ rustc-hash = "1.1.0"
 either = "1.5.3"
 anymap = "0.12.1"
 drop_bomb = "0.1.4"
+fst = { version = "0.4", default-features = false }
+itertools = "0.9.0"
+indexmap = "1.4.0"
 
 stdx = { path = "../stdx" }
 
diff --git a/crates/ra_hir_def/src/attr.rs b/crates/ra_hir_def/src/attr.rs
index 8b6c0bede..2eeba0572 100644
--- a/crates/ra_hir_def/src/attr.rs
+++ b/crates/ra_hir_def/src/attr.rs
@@ -87,12 +87,18 @@ impl Attrs {
     }
 
     pub(crate) fn new(owner: &dyn AttrsOwner, hygiene: &Hygiene) -> Attrs {
+        let docs = ast::CommentIter::from_syntax_node(owner.syntax()).doc_comment_text().map(
+            |docs_text| Attr {
+                input: Some(AttrInput::Literal(SmolStr::new(docs_text))),
+                path: ModPath::from(hir_expand::name!(doc)),
+            },
+        );
         let mut attrs = owner.attrs().peekable();
         let entries = if attrs.peek().is_none() {
             // Avoid heap allocation
             None
         } else {
-            Some(attrs.flat_map(|ast| Attr::from_src(ast, hygiene)).collect())
+            Some(attrs.flat_map(|ast| Attr::from_src(ast, hygiene)).chain(docs).collect())
         };
         Attrs { entries }
     }
diff --git a/crates/ra_hir_def/src/body.rs b/crates/ra_hir_def/src/body.rs
index 273036cee..4f2350915 100644
--- a/crates/ra_hir_def/src/body.rs
+++ b/crates/ra_hir_def/src/body.rs
@@ -97,7 +97,7 @@ impl Expander {
 
         let macro_call = InFile::new(self.current_file_id, &macro_call);
 
-        if let Some(call_id) = macro_call.as_call_id(db, |path| {
+        if let Some(call_id) = macro_call.as_call_id(db, self.crate_def_map.krate, |path| {
             if let Some(local_scope) = local_scope {
                 if let Some(def) = path.as_ident().and_then(|n| local_scope.get_legacy_macro(n)) {
                     return Some(def);
diff --git a/crates/ra_hir_def/src/data.rs b/crates/ra_hir_def/src/data.rs
index e2130d931..53599e74a 100644
--- a/crates/ra_hir_def/src/data.rs
+++ b/crates/ra_hir_def/src/data.rs
@@ -34,6 +34,7 @@ pub struct FunctionData {
     /// True if the first param is `self`. This is relevant to decide whether this
     /// can be called as a method.
     pub has_self_param: bool,
+    pub is_unsafe: bool,
     pub visibility: RawVisibility,
 }
 
@@ -85,17 +86,20 @@ impl FunctionData {
             ret_type
         };
 
+        let is_unsafe = src.value.unsafe_token().is_some();
+
         let vis_default = RawVisibility::default_for_container(loc.container);
         let visibility =
             RawVisibility::from_ast_with_default(db, vis_default, src.map(|s| s.visibility()));
 
-        let sig = FunctionData { name, params, ret_type, has_self_param, visibility, attrs };
+        let sig =
+            FunctionData { name, params, ret_type, has_self_param, is_unsafe, visibility, attrs };
         Arc::new(sig)
     }
 }
 
 fn desugar_future_path(orig: TypeRef) -> Path {
-    let path = path![std::future::Future];
+    let path = path![core::future::Future];
     let mut generic_args: Vec<_> = std::iter::repeat(None).take(path.segments.len() - 1).collect();
     let mut last = GenericArgs::empty();
     last.bindings.push(AssociatedTypeBinding {
diff --git a/crates/ra_hir_def/src/db.rs b/crates/ra_hir_def/src/db.rs
index 945a0025e..10cc26480 100644
--- a/crates/ra_hir_def/src/db.rs
+++ b/crates/ra_hir_def/src/db.rs
@@ -1,7 +1,7 @@
 //! Defines database & queries for name resolution.
 use std::sync::Arc;
 
-use hir_expand::{db::AstDatabase, name::Name, HirFileId};
+use hir_expand::{db::AstDatabase, HirFileId};
 use ra_db::{salsa, CrateId, SourceDatabase, Upcast};
 use ra_prof::profile;
 use ra_syntax::SmolStr;
@@ -12,13 +12,10 @@ use crate::{
     body::{scope::ExprScopes, Body, BodySourceMap},
     data::{ConstData, FunctionData, ImplData, StaticData, TraitData, TypeAliasData},
     docs::Documentation,
-    find_path,
     generics::GenericParams,
-    item_scope::ItemInNs,
+    import_map::ImportMap,
     lang_item::{LangItemTarget, LangItems},
     nameres::{raw::RawItems, CrateDefMap},
-    path::ModPath,
-    visibility::Visibility,
     AttrDefId, ConstId, ConstLoc, DefWithBodyId, EnumId, EnumLoc, FunctionId, FunctionLoc,
     GenericDefId, ImplId, ImplLoc, ModuleId, StaticId, StaticLoc, StructId, StructLoc, TraitId,
     TraitLoc, TypeAliasId, TypeAliasLoc, UnionId, UnionLoc,
@@ -113,15 +110,8 @@ pub trait DefDatabase: InternDatabase + AstDatabase + Upcast<dyn AstDatabase> {
     #[salsa::invoke(Documentation::documentation_query)]
     fn documentation(&self, def: AttrDefId) -> Option<Documentation>;
 
-    #[salsa::invoke(find_path::importable_locations_of_query)]
-    fn importable_locations_of(
-        &self,
-        item: ItemInNs,
-        krate: CrateId,
-    ) -> Arc<[(ModuleId, Name, Visibility)]>;
-
-    #[salsa::invoke(find_path::find_path_inner_query)]
-    fn find_path_inner(&self, item: ItemInNs, from: ModuleId, max_len: usize) -> Option<ModPath>;
+    #[salsa::invoke(ImportMap::import_map_query)]
+    fn import_map(&self, krate: CrateId) -> Arc<ImportMap>;
 }
 
 fn crate_def_map_wait(db: &impl DefDatabase, krate: CrateId) -> Arc<CrateDefMap> {
diff --git a/crates/ra_hir_def/src/docs.rs b/crates/ra_hir_def/src/docs.rs
index b221ae1ce..2630b3d89 100644
--- a/crates/ra_hir_def/src/docs.rs
+++ b/crates/ra_hir_def/src/docs.rs
@@ -29,6 +29,13 @@ impl Documentation {
         Documentation(s.into())
     }
 
+    pub fn from_ast<N>(node: &N) -> Option<Documentation>
+    where
+        N: ast::DocCommentsOwner + ast::AttrsOwner,
+    {
+        docs_from_ast(node)
+    }
+
     pub fn as_str(&self) -> &str {
         &*self.0
     }
@@ -70,6 +77,45 @@ impl Documentation {
     }
 }
 
-pub(crate) fn docs_from_ast(node: &impl ast::DocCommentsOwner) -> Option<Documentation> {
-    node.doc_comment_text().map(|it| Documentation::new(&it))
+pub(crate) fn docs_from_ast<N>(node: &N) -> Option<Documentation>
+where
+    N: ast::DocCommentsOwner + ast::AttrsOwner,
+{
+    let doc_comment_text = node.doc_comment_text();
+    let doc_attr_text = expand_doc_attrs(node);
+    let docs = merge_doc_comments_and_attrs(doc_comment_text, doc_attr_text);
+    docs.map(|it| Documentation::new(&it))
+}
+
+fn merge_doc_comments_and_attrs(
+    doc_comment_text: Option<String>,
+    doc_attr_text: Option<String>,
+) -> Option<String> {
+    match (doc_comment_text, doc_attr_text) {
+        (Some(mut comment_text), Some(attr_text)) => {
+            comment_text.push_str("\n\n");
+            comment_text.push_str(&attr_text);
+            Some(comment_text)
+        }
+        (Some(comment_text), None) => Some(comment_text),
+        (None, Some(attr_text)) => Some(attr_text),
+        (None, None) => None,
+    }
+}
+
+fn expand_doc_attrs(owner: &dyn ast::AttrsOwner) -> Option<String> {
+    let mut docs = String::new();
+    for attr in owner.attrs() {
+        if let Some(("doc", value)) =
+            attr.as_simple_key_value().as_ref().map(|(k, v)| (k.as_str(), v.as_str()))
+        {
+            docs.push_str(value);
+            docs.push_str("\n\n");
+        }
+    }
+    if docs.is_empty() {
+        None
+    } else {
+        Some(docs.trim_end_matches("\n\n").to_owned())
+    }
 }
diff --git a/crates/ra_hir_def/src/find_path.rs b/crates/ra_hir_def/src/find_path.rs
index 4db798473..06701a830 100644
--- a/crates/ra_hir_def/src/find_path.rs
+++ b/crates/ra_hir_def/src/find_path.rs
@@ -1,9 +1,8 @@
 //! An algorithm to find a path to refer to a certain item.
 
-use std::sync::Arc;
-
 use hir_expand::name::{known, AsName, Name};
 use ra_prof::profile;
+use rustc_hash::FxHashSet;
 use test_utils::mark;
 
 use crate::{
@@ -11,7 +10,7 @@ use crate::{
     item_scope::ItemInNs,
     path::{ModPath, PathKind},
     visibility::Visibility,
-    CrateId, ModuleDefId, ModuleId,
+    ModuleDefId, ModuleId,
 };
 
 // FIXME: handle local items
@@ -20,7 +19,7 @@ use crate::{
 /// *from where* you're referring to the item, hence the `from` parameter.
 pub fn find_path(db: &dyn DefDatabase, item: ItemInNs, from: ModuleId) -> Option<ModPath> {
     let _p = profile("find_path");
-    db.find_path_inner(item, from, MAX_PATH_LEN)
+    find_path_inner(db, item, from, MAX_PATH_LEN)
 }
 
 const MAX_PATH_LEN: usize = 15;
@@ -36,20 +35,9 @@ impl ModPath {
         let first_segment = self.segments.first();
         first_segment == Some(&known::alloc) || first_segment == Some(&known::core)
     }
-
-    fn len(&self) -> usize {
-        self.segments.len()
-            + match self.kind {
-                PathKind::Plain => 0,
-                PathKind::Super(i) => i as usize,
-                PathKind::Crate => 1,
-                PathKind::Abs => 0,
-                PathKind::DollarCrate(_) => 1,
-            }
-    }
 }
 
-pub(crate) fn find_path_inner_query(
+fn find_path_inner(
     db: &dyn DefDatabase,
     item: ItemInNs,
     from: ModuleId,
@@ -133,31 +121,67 @@ pub(crate) fn find_path_inner_query(
     }
 
     // - otherwise, look for modules containing (reexporting) it and import it from one of those
+
     let crate_root = ModuleId { local_id: def_map.root, krate: from.krate };
     let crate_attrs = db.attrs(crate_root.into());
     let prefer_no_std = crate_attrs.by_key("no_std").exists();
-    let importable_locations = find_importable_locations(db, item, from);
     let mut best_path = None;
     let mut best_path_len = max_len;
-    for (module_id, name) in importable_locations {
-        let mut path = match db.find_path_inner(
-            ItemInNs::Types(ModuleDefId::ModuleId(module_id)),
-            from,
-            best_path_len - 1,
-        ) {
-            None => continue,
-            Some(path) => path,
-        };
-        path.segments.push(name);
 
-        let new_path = if let Some(best_path) = best_path {
-            select_best_path(best_path, path, prefer_no_std)
-        } else {
-            path
-        };
-        best_path_len = new_path.len();
-        best_path = Some(new_path);
+    if item.krate(db) == Some(from.krate) {
+        // Item was defined in the same crate that wants to import it. It cannot be found in any
+        // dependency in this case.
+
+        let local_imports = find_local_import_locations(db, item, from);
+        for (module_id, name) in local_imports {
+            if let Some(mut path) = find_path_inner(
+                db,
+                ItemInNs::Types(ModuleDefId::ModuleId(module_id)),
+                from,
+                best_path_len - 1,
+            ) {
+                path.segments.push(name);
+
+                let new_path = if let Some(best_path) = best_path {
+                    select_best_path(best_path, path, prefer_no_std)
+                } else {
+                    path
+                };
+                best_path_len = new_path.len();
+                best_path = Some(new_path);
+            }
+        }
+    } else {
+        // Item was defined in some upstream crate. This means that it must be exported from one,
+        // too (unless we can't name it at all). It could *also* be (re)exported by the same crate
+        // that wants to import it here, but we always prefer to use the external path here.
+
+        let crate_graph = db.crate_graph();
+        let extern_paths = crate_graph[from.krate].dependencies.iter().filter_map(|dep| {
+            let import_map = db.import_map(dep.crate_id);
+            import_map.import_info_for(item).and_then(|info| {
+                // Determine best path for containing module and append last segment from `info`.
+                let mut path = find_path_inner(
+                    db,
+                    ItemInNs::Types(ModuleDefId::ModuleId(info.container)),
+                    from,
+                    best_path_len - 1,
+                )?;
+                path.segments.push(info.path.segments.last().unwrap().clone());
+                Some(path)
+            })
+        });
+
+        for path in extern_paths {
+            let new_path = if let Some(best_path) = best_path {
+                select_best_path(best_path, path, prefer_no_std)
+            } else {
+                path
+            };
+            best_path = Some(new_path);
+        }
     }
+
     best_path
 }
 
@@ -185,69 +209,86 @@ fn select_best_path(old_path: ModPath, new_path: ModPath, prefer_no_std: bool) -
     }
 }
 
-fn find_importable_locations(
+/// Finds locations in `from.krate` from which `item` can be imported by `from`.
+fn find_local_import_locations(
     db: &dyn DefDatabase,
     item: ItemInNs,
     from: ModuleId,
 ) -> Vec<(ModuleId, Name)> {
-    let crate_graph = db.crate_graph();
-    let mut result = Vec::new();
-    // We only look in the crate from which we are importing, and the direct
-    // dependencies. We cannot refer to names from transitive dependencies
-    // directly (only through reexports in direct dependencies).
-    for krate in Some(from.krate)
-        .into_iter()
-        .chain(crate_graph[from.krate].dependencies.iter().map(|dep| dep.crate_id))
-    {
-        result.extend(
-            db.importable_locations_of(item, krate)
-                .iter()
-                .filter(|(_, _, vis)| vis.is_visible_from(db, from))
-                .map(|(m, n, _)| (*m, n.clone())),
-        );
-    }
-    result
-}
+    let _p = profile("find_local_import_locations");
+
+    // `from` can import anything below `from` with visibility of at least `from`, and anything
+    // above `from` with any visibility. That means we do not need to descend into private siblings
+    // of `from` (and similar).
+
+    let def_map = db.crate_def_map(from.krate);
+
+    // Compute the initial worklist. We start with all direct child modules of `from` as well as all
+    // of its (recursive) parent modules.
+    let data = &def_map.modules[from.local_id];
+    let mut worklist = data
+        .children
+        .values()
+        .map(|child| ModuleId { krate: from.krate, local_id: *child })
+        .collect::<Vec<_>>();
+    let mut parent = data.parent;
+    while let Some(p) = parent {
+        worklist.push(ModuleId { krate: from.krate, local_id: p });
+        parent = def_map.modules[p].parent;
+    }
+
+    let mut seen: FxHashSet<_> = FxHashSet::default();
+
+    let mut locations = Vec::new();
+    while let Some(module) = worklist.pop() {
+        if !seen.insert(module) {
+            continue; // already processed this module
+        }
+
+        let ext_def_map;
+        let data = if module.krate == from.krate {
+            &def_map[module.local_id]
+        } else {
+            // The crate might reexport a module defined in another crate.
+            ext_def_map = db.crate_def_map(module.krate);
+            &ext_def_map[module.local_id]
+        };
 
-/// Collects all locations from which we might import the item in a particular
-/// crate. These include the original definition of the item, and any
-/// non-private `use`s.
-///
-/// Note that the crate doesn't need to be the one in which the item is defined;
-/// it might be re-exported in other crates.
-pub(crate) fn importable_locations_of_query(
-    db: &dyn DefDatabase,
-    item: ItemInNs,
-    krate: CrateId,
-) -> Arc<[(ModuleId, Name, Visibility)]> {
-    let _p = profile("importable_locations_of_query");
-    let def_map = db.crate_def_map(krate);
-    let mut result = Vec::new();
-    for (local_id, data) in def_map.modules.iter() {
         if let Some((name, vis)) = data.scope.name_of(item) {
-            let is_private = if let Visibility::Module(private_to) = vis {
-                private_to.local_id == local_id
-            } else {
-                false
-            };
-            let is_original_def = if let Some(module_def_id) = item.as_module_def_id() {
-                data.scope.declarations().any(|it| it == module_def_id)
-            } else {
-                false
-            };
-            if is_private && !is_original_def {
+            if vis.is_visible_from(db, from) {
+                let is_private = if let Visibility::Module(private_to) = vis {
+                    private_to.local_id == module.local_id
+                } else {
+                    false
+                };
+                let is_original_def = if let Some(module_def_id) = item.as_module_def_id() {
+                    data.scope.declarations().any(|it| it == module_def_id)
+                } else {
+                    false
+                };
+
                 // Ignore private imports. these could be used if we are
                 // in a submodule of this module, but that's usually not
                 // what the user wants; and if this module can import
                 // the item and we're a submodule of it, so can we.
                 // Also this keeps the cached data smaller.
-                continue;
+                if !is_private || is_original_def {
+                    locations.push((module, name.clone()));
+                }
+            }
+        }
+
+        // Descend into all modules visible from `from`.
+        for (_, per_ns) in data.scope.entries() {
+            if let Some((ModuleDefId::ModuleId(module), vis)) = per_ns.take_types_vis() {
+                if vis.is_visible_from(db, from) {
+                    worklist.push(module);
+                }
             }
-            result.push((ModuleId { krate, local_id }, name.clone(), vis));
         }
     }
 
-    Arc::from(result)
+    locations
 }
 
 #[cfg(test)]
@@ -264,8 +305,8 @@ mod tests {
     /// `code` needs to contain a cursor marker; checks that `find_path` for the
     /// item the `path` refers to returns that same path when called from the
     /// module the cursor is in.
-    fn check_found_path(code: &str, path: &str) {
-        let (db, pos) = TestDB::with_position(code);
+    fn check_found_path(ra_fixture: &str, path: &str) {
+        let (db, pos) = TestDB::with_position(ra_fixture);
         let module = db.module_for_file(pos.file_id);
         let parsed_path_file = ra_syntax::SourceFile::parse(&format!("use {};", path));
         let ast_path = parsed_path_file
@@ -396,6 +437,44 @@ mod tests {
     }
 
     #[test]
+    fn partially_imported() {
+        // Tests that short paths are used even for external items, when parts of the path are
+        // already in scope.
+        check_found_path(
+            r#"
+            //- /main.rs crate:main deps:ra_syntax
+
+            use ra_syntax::ast;
+            <|>
+
+            //- /lib.rs crate:ra_syntax
+            pub mod ast {
+                pub enum ModuleItem {
+                    A, B, C,
+                }
+            }
+        "#,
+            "ast::ModuleItem",
+        );
+
+        check_found_path(
+            r#"
+            //- /main.rs crate:main deps:ra_syntax
+
+            <|>
+
+            //- /lib.rs crate:ra_syntax
+            pub mod ast {
+                pub enum ModuleItem {
+                    A, B, C,
+                }
+            }
+        "#,
+            "ra_syntax::ast::ModuleItem",
+        );
+    }
+
+    #[test]
     fn same_crate_reexport() {
         let code = r#"
             //- /main.rs
diff --git a/crates/ra_hir_def/src/import_map.rs b/crates/ra_hir_def/src/import_map.rs
new file mode 100644
index 000000000..68e20d06b
--- /dev/null
+++ b/crates/ra_hir_def/src/import_map.rs
@@ -0,0 +1,679 @@
+//! A map of all publicly exported items in a crate.
+
+use std::{cmp::Ordering, fmt, hash::BuildHasherDefault, sync::Arc};
+
+use fst::{self, Streamer};
+use indexmap::{map::Entry, IndexMap};
+use ra_db::CrateId;
+use rustc_hash::FxHasher;
+
+use crate::{
+    db::DefDatabase,
+    item_scope::ItemInNs,
+    path::{ModPath, PathKind},
+    visibility::Visibility,
+    ModuleDefId, ModuleId,
+};
+
+type FxIndexMap<K, V> = IndexMap<K, V, BuildHasherDefault<FxHasher>>;
+
+/// Item import details stored in the `ImportMap`.
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct ImportInfo {
+    /// A path that can be used to import the item, relative to the crate's root.
+    pub path: ModPath,
+    /// The module containing this item.
+    pub container: ModuleId,
+}
+
+/// A map from publicly exported items to the path needed to import/name them from a downstream
+/// crate.
+///
+/// Reexports of items are taken into account, ie. if something is exported under multiple
+/// names, the one with the shortest import path will be used.
+///
+/// Note that all paths are relative to the containing crate's root, so the crate name still needs
+/// to be prepended to the `ModPath` before the path is valid.
+pub struct ImportMap {
+    map: FxIndexMap<ItemInNs, ImportInfo>,
+
+    /// List of keys stored in `map`, sorted lexicographically by their `ModPath`. Indexed by the
+    /// values returned by running `fst`.
+    ///
+    /// Since a path can refer to multiple items due to namespacing, we store all items with the
+    /// same path right after each other. This allows us to find all items after the FST gives us
+    /// the index of the first one.
+    importables: Vec<ItemInNs>,
+    fst: fst::Map<Vec<u8>>,
+}
+
+impl ImportMap {
+    pub fn import_map_query(db: &dyn DefDatabase, krate: CrateId) -> Arc<Self> {
+        let _p = ra_prof::profile("import_map_query");
+        let def_map = db.crate_def_map(krate);
+        let mut import_map = FxIndexMap::with_capacity_and_hasher(64, Default::default());
+
+        // We look only into modules that are public(ly reexported), starting with the crate root.
+        let empty = ModPath { kind: PathKind::Plain, segments: vec![] };
+        let root = ModuleId { krate, local_id: def_map.root };
+        let mut worklist = vec![(root, empty)];
+        while let Some((module, mod_path)) = worklist.pop() {
+            let ext_def_map;
+            let mod_data = if module.krate == krate {
+                &def_map[module.local_id]
+            } else {
+                // The crate might reexport a module defined in another crate.
+                ext_def_map = db.crate_def_map(module.krate);
+                &ext_def_map[module.local_id]
+            };
+
+            let visible_items = mod_data.scope.entries().filter_map(|(name, per_ns)| {
+                let per_ns = per_ns.filter_visibility(|vis| vis == Visibility::Public);
+                if per_ns.is_none() {
+                    None
+                } else {
+                    Some((name, per_ns))
+                }
+            });
+
+            for (name, per_ns) in visible_items {
+                let mk_path = || {
+                    let mut path = mod_path.clone();
+                    path.segments.push(name.clone());
+                    path
+                };
+
+                for item in per_ns.iter_items() {
+                    let path = mk_path();
+                    match import_map.entry(item) {
+                        Entry::Vacant(entry) => {
+                            entry.insert(ImportInfo { path, container: module });
+                        }
+                        Entry::Occupied(mut entry) => {
+                            // If the new path is shorter, prefer that one.
+                            if path.len() < entry.get().path.len() {
+                                *entry.get_mut() = ImportInfo { path, container: module };
+                            } else {
+                                continue;
+                            }
+                        }
+                    }
+
+                    // If we've just added a path to a module, descend into it. We might traverse
+                    // modules multiple times, but only if the new path to it is shorter than the
+                    // first (else we `continue` above).
+                    if let Some(ModuleDefId::ModuleId(mod_id)) = item.as_module_def_id() {
+                        worklist.push((mod_id, mk_path()));
+                    }
+                }
+            }
+        }
+
+        let mut importables = import_map.iter().collect::<Vec<_>>();
+
+        importables.sort_by(cmp);
+
+        // Build the FST, taking care not to insert duplicate values.
+
+        let mut builder = fst::MapBuilder::memory();
+        let mut last_batch_start = 0;
+
+        for idx in 0..importables.len() {
+            if let Some(next_item) = importables.get(idx + 1) {
+                if cmp(&importables[last_batch_start], next_item) == Ordering::Equal {
+                    continue;
+                }
+            }
+
+            let start = last_batch_start;
+            last_batch_start = idx + 1;
+
+            let key = fst_path(&importables[start].1.path);
+
+            builder.insert(key, start as u64).unwrap();
+        }
+
+        let fst = fst::Map::new(builder.into_inner().unwrap()).unwrap();
+        let importables = importables.iter().map(|(item, _)| **item).collect();
+
+        Arc::new(Self { map: import_map, fst, importables })
+    }
+
+    /// Returns the `ModPath` needed to import/mention `item`, relative to this crate's root.
+    pub fn path_of(&self, item: ItemInNs) -> Option<&ModPath> {
+        Some(&self.map.get(&item)?.path)
+    }
+
+    pub fn import_info_for(&self, item: ItemInNs) -> Option<&ImportInfo> {
+        self.map.get(&item)
+    }
+}
+
+impl PartialEq for ImportMap {
+    fn eq(&self, other: &Self) -> bool {
+        // `fst` and `importables` are built from `map`, so we don't need to compare them.
+        self.map == other.map
+    }
+}
+
+impl Eq for ImportMap {}
+
+impl fmt::Debug for ImportMap {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut importable_paths: Vec<_> = self
+            .map
+            .iter()
+            .map(|(item, info)| {
+                let ns = match item {
+                    ItemInNs::Types(_) => "t",
+                    ItemInNs::Values(_) => "v",
+                    ItemInNs::Macros(_) => "m",
+                };
+                format!("- {} ({})", info.path, ns)
+            })
+            .collect();
+
+        importable_paths.sort();
+        f.write_str(&importable_paths.join("\n"))
+    }
+}
+
+fn fst_path(path: &ModPath) -> String {
+    let mut s = path.to_string();
+    s.make_ascii_lowercase();
+    s
+}
+
+fn cmp((_, lhs): &(&ItemInNs, &ImportInfo), (_, rhs): &(&ItemInNs, &ImportInfo)) -> Ordering {
+    let lhs_str = fst_path(&lhs.path);
+    let rhs_str = fst_path(&rhs.path);
+    lhs_str.cmp(&rhs_str)
+}
+
+#[derive(Debug)]
+pub struct Query {
+    query: String,
+    lowercased: String,
+    anchor_end: bool,
+    case_sensitive: bool,
+    limit: usize,
+}
+
+impl Query {
+    pub fn new(query: &str) -> Self {
+        Self {
+            lowercased: query.to_lowercase(),
+            query: query.to_string(),
+            anchor_end: false,
+            case_sensitive: false,
+            limit: usize::max_value(),
+        }
+    }
+
+    /// Only returns items whose paths end with the (case-insensitive) query string as their last
+    /// segment.
+    pub fn anchor_end(self) -> Self {
+        Self { anchor_end: true, ..self }
+    }
+
+    /// Limits the returned number of items to `limit`.
+    pub fn limit(self, limit: usize) -> Self {
+        Self { limit, ..self }
+    }
+
+    /// Respect casing of the query string when matching.
+    pub fn case_sensitive(self) -> Self {
+        Self { case_sensitive: true, ..self }
+    }
+}
+
+/// Searches dependencies of `krate` for an importable path matching `query`.
+///
+/// This returns a list of items that could be imported from dependencies of `krate`.
+pub fn search_dependencies<'a>(
+    db: &'a dyn DefDatabase,
+    krate: CrateId,
+    query: Query,
+) -> Vec<ItemInNs> {
+    let _p = ra_prof::profile("search_dependencies").detail(|| format!("{:?}", query));
+
+    let graph = db.crate_graph();
+    let import_maps: Vec<_> =
+        graph[krate].dependencies.iter().map(|dep| db.import_map(dep.crate_id)).collect();
+
+    let automaton = fst::automaton::Subsequence::new(&query.lowercased);
+
+    let mut op = fst::map::OpBuilder::new();
+    for map in &import_maps {
+        op = op.add(map.fst.search(&automaton));
+    }
+
+    let mut stream = op.union();
+    let mut res = Vec::new();
+    while let Some((_, indexed_values)) = stream.next() {
+        for indexed_value in indexed_values {
+            let import_map = &import_maps[indexed_value.index];
+            let importables = &import_map.importables[indexed_value.value as usize..];
+
+            // Path shared by the importable items in this group.
+            let path = &import_map.map[&importables[0]].path;
+
+            if query.anchor_end {
+                // Last segment must match query.
+                let last = path.segments.last().unwrap().to_string();
+                if last.to_lowercase() != query.lowercased {
+                    continue;
+                }
+            }
+
+            // Add the items from this `ModPath` group. Those are all subsequent items in
+            // `importables` whose paths match `path`.
+            let iter = importables.iter().copied().take_while(|item| {
+                let item_path = &import_map.map[item].path;
+                fst_path(item_path) == fst_path(path)
+            });
+
+            if query.case_sensitive {
+                // FIXME: This does not do a subsequence match.
+                res.extend(iter.filter(|item| {
+                    let item_path = &import_map.map[item].path;
+                    item_path.to_string().contains(&query.query)
+                }));
+            } else {
+                res.extend(iter);
+            }
+
+            if res.len() >= query.limit {
+                res.truncate(query.limit);
+                return res;
+            }
+        }
+    }
+
+    res
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_db::TestDB;
+    use insta::assert_snapshot;
+    use itertools::Itertools;
+    use ra_db::fixture::WithFixture;
+    use ra_db::{SourceDatabase, Upcast};
+
+    fn import_map(ra_fixture: &str) -> String {
+        let db = TestDB::with_files(ra_fixture);
+        let crate_graph = db.crate_graph();
+
+        let s = crate_graph
+            .iter()
+            .filter_map(|krate| {
+                let cdata = &crate_graph[krate];
+                let name = cdata.display_name.as_ref()?;
+
+                let map = db.import_map(krate);
+
+                Some(format!("{}:\n{:?}", name, map))
+            })
+            .join("\n");
+        s
+    }
+
+    fn search_dependencies_of(ra_fixture: &str, krate_name: &str, query: Query) -> String {
+        let db = TestDB::with_files(ra_fixture);
+        let crate_graph = db.crate_graph();
+        let krate = crate_graph
+            .iter()
+            .find(|krate| {
+                crate_graph[*krate].display_name.as_ref().map(|n| n.to_string())
+                    == Some(krate_name.to_string())
+            })
+            .unwrap();
+
+        search_dependencies(db.upcast(), krate, query)
+            .into_iter()
+            .filter_map(|item| {
+                let mark = match item {
+                    ItemInNs::Types(_) => "t",
+                    ItemInNs::Values(_) => "v",
+                    ItemInNs::Macros(_) => "m",
+                };
+                item.krate(db.upcast()).map(|krate| {
+                    let map = db.import_map(krate);
+                    let path = map.path_of(item).unwrap();
+                    format!(
+                        "{}::{} ({})",
+                        crate_graph[krate].display_name.as_ref().unwrap(),
+                        path,
+                        mark
+                    )
+                })
+            })
+            .join("\n")
+    }
+
+    #[test]
+    fn smoke() {
+        let map = import_map(
+            r"
+            //- /main.rs crate:main deps:lib
+
+            mod private {
+                pub use lib::Pub;
+                pub struct InPrivateModule;
+            }
+
+            pub mod publ1 {
+                use lib::Pub;
+            }
+
+            pub mod real_pub {
+                pub use lib::Pub;
+            }
+            pub mod real_pu2 { // same path length as above
+                pub use lib::Pub;
+            }
+
+            //- /lib.rs crate:lib
+            pub struct Pub {}
+            pub struct Pub2; // t + v
+            struct Priv;
+        ",
+        );
+
+        assert_snapshot!(map, @r###"
+        main:
+        - publ1 (t)
+        - real_pu2 (t)
+        - real_pub (t)
+        - real_pub::Pub (t)
+        lib:
+        - Pub (t)
+        - Pub2 (t)
+        - Pub2 (v)
+        "###);
+    }
+
+    #[test]
+    fn prefers_shortest_path() {
+        let map = import_map(
+            r"
+            //- /main.rs crate:main
+
+            pub mod sub {
+                pub mod subsub {
+                    pub struct Def {}
+                }
+
+                pub use super::sub::subsub::Def;
+            }
+        ",
+        );
+
+        assert_snapshot!(map, @r###"
+        main:
+        - sub (t)
+        - sub::Def (t)
+        - sub::subsub (t)
+        "###);
+    }
+
+    #[test]
+    fn type_reexport_cross_crate() {
+        // Reexports need to be visible from a crate, even if the original crate exports the item
+        // at a shorter path.
+        let map = import_map(
+            r"
+            //- /main.rs crate:main deps:lib
+            pub mod m {
+                pub use lib::S;
+            }
+            //- /lib.rs crate:lib
+            pub struct S;
+        ",
+        );
+
+        assert_snapshot!(map, @r###"
+        main:
+        - m (t)
+        - m::S (t)
+        - m::S (v)
+        lib:
+        - S (t)
+        - S (v)
+        "###);
+    }
+
+    #[test]
+    fn macro_reexport() {
+        let map = import_map(
+            r"
+            //- /main.rs crate:main deps:lib
+            pub mod m {
+                pub use lib::pub_macro;
+            }
+            //- /lib.rs crate:lib
+            #[macro_export]
+            macro_rules! pub_macro {
+                () => {};
+            }
+        ",
+        );
+
+        assert_snapshot!(map, @r###"
+        main:
+        - m (t)
+        - m::pub_macro (m)
+        lib:
+        - pub_macro (m)
+        "###);
+    }
+
+    #[test]
+    fn module_reexport() {
+        // Reexporting modules from a dependency adds all contents to the import map.
+        let map = import_map(
+            r"
+            //- /main.rs crate:main deps:lib
+            pub use lib::module as reexported_module;
+            //- /lib.rs crate:lib
+            pub mod module {
+                pub struct S;
+            }
+        ",
+        );
+
+        assert_snapshot!(map, @r###"
+        main:
+        - reexported_module (t)
+        - reexported_module::S (t)
+        - reexported_module::S (v)
+        lib:
+        - module (t)
+        - module::S (t)
+        - module::S (v)
+        "###);
+    }
+
+    #[test]
+    fn cyclic_module_reexport() {
+        // A cyclic reexport does not hang.
+        let map = import_map(
+            r"
+            //- /lib.rs crate:lib
+            pub mod module {
+                pub struct S;
+                pub use super::sub::*;
+            }
+
+            pub mod sub {
+                pub use super::module;
+            }
+        ",
+        );
+
+        assert_snapshot!(map, @r###"
+        lib:
+        - module (t)
+        - module::S (t)
+        - module::S (v)
+        - sub (t)
+        "###);
+    }
+
+    #[test]
+    fn private_macro() {
+        let map = import_map(
+            r"
+            //- /lib.rs crate:lib
+            macro_rules! private_macro {
+                () => {};
+            }
+        ",
+        );
+
+        assert_snapshot!(map, @r###"
+        lib:
+        "###);
+    }
+
+    #[test]
+    fn namespacing() {
+        let map = import_map(
+            r"
+            //- /lib.rs crate:lib
+            pub struct Thing;     // t + v
+            #[macro_export]
+            macro_rules! Thing {  // m
+                () => {};
+            }
+        ",
+        );
+
+        assert_snapshot!(map, @r###"
+        lib:
+        - Thing (m)
+        - Thing (t)
+        - Thing (v)
+        "###);
+
+        let map = import_map(
+            r"
+            //- /lib.rs crate:lib
+            pub mod Thing {}      // t
+            #[macro_export]
+            macro_rules! Thing {  // m
+                () => {};
+            }
+        ",
+        );
+
+        assert_snapshot!(map, @r###"
+        lib:
+        - Thing (m)
+        - Thing (t)
+        "###);
+    }
+
+    #[test]
+    fn search() {
+        let ra_fixture = r#"
+            //- /main.rs crate:main deps:dep
+            //- /dep.rs crate:dep deps:tdep
+            use tdep::fmt as fmt_dep;
+            pub mod fmt {
+                pub trait Display {
+                    fn fmt();
+                }
+            }
+            #[macro_export]
+            macro_rules! Fmt {
+                () => {};
+            }
+            pub struct Fmt;
+
+            pub fn format() {}
+            pub fn no() {}
+
+            //- /tdep.rs crate:tdep
+            pub mod fmt {
+                pub struct NotImportableFromMain;
+            }
+        "#;
+
+        let res = search_dependencies_of(ra_fixture, "main", Query::new("fmt"));
+        assert_snapshot!(res, @r###"
+        dep::fmt (t)
+        dep::Fmt (t)
+        dep::Fmt (v)
+        dep::Fmt (m)
+        dep::fmt::Display (t)
+        dep::format (v)
+        "###);
+
+        let res = search_dependencies_of(ra_fixture, "main", Query::new("fmt").anchor_end());
+        assert_snapshot!(res, @r###"
+        dep::fmt (t)
+        dep::Fmt (t)
+        dep::Fmt (v)
+        dep::Fmt (m)
+        "###);
+    }
+
+    #[test]
+    fn search_casing() {
+        let ra_fixture = r#"
+            //- /main.rs crate:main deps:dep
+            //- /dep.rs crate:dep
+
+            pub struct fmt;
+            pub struct FMT;
+        "#;
+
+        let res = search_dependencies_of(ra_fixture, "main", Query::new("FMT"));
+
+        assert_snapshot!(res, @r###"
+        dep::fmt (t)
+        dep::fmt (v)
+        dep::FMT (t)
+        dep::FMT (v)
+        "###);
+
+        let res = search_dependencies_of(ra_fixture, "main", Query::new("FMT").case_sensitive());
+
+        assert_snapshot!(res, @r###"
+        dep::FMT (t)
+        dep::FMT (v)
+        "###);
+    }
+
+    #[test]
+    fn search_limit() {
+        let res = search_dependencies_of(
+            r#"
+        //- /main.rs crate:main deps:dep
+        //- /dep.rs crate:dep
+        pub mod fmt {
+            pub trait Display {
+                fn fmt();
+            }
+        }
+        #[macro_export]
+        macro_rules! Fmt {
+            () => {};
+        }
+        pub struct Fmt;
+
+        pub fn format() {}
+        pub fn no() {}
+    "#,
+            "main",
+            Query::new("").limit(2),
+        );
+        assert_snapshot!(res, @r###"
+        dep::fmt (t)
+        dep::Fmt (t)
+        "###);
+    }
+}
diff --git a/crates/ra_hir_def/src/item_scope.rs b/crates/ra_hir_def/src/item_scope.rs
index fc15948ad..b03ba939a 100644
--- a/crates/ra_hir_def/src/item_scope.rs
+++ b/crates/ra_hir_def/src/item_scope.rs
@@ -3,11 +3,12 @@
 
 use hir_expand::name::Name;
 use once_cell::sync::Lazy;
+use ra_db::CrateId;
 use rustc_hash::FxHashMap;
 
 use crate::{
-    per_ns::PerNs, visibility::Visibility, AdtId, BuiltinType, ImplId, MacroDefId, ModuleDefId,
-    TraitId,
+    db::DefDatabase, per_ns::PerNs, visibility::Visibility, AdtId, BuiltinType, HasModule, ImplId,
+    Lookup, MacroDefId, ModuleDefId, TraitId,
 };
 
 #[derive(Debug, Default, PartialEq, Eq)]
@@ -203,4 +204,22 @@ impl ItemInNs {
             ItemInNs::Macros(_) => None,
         }
     }
+
+    /// Returns the crate defining this item (or `None` if `self` is built-in).
+    pub fn krate(&self, db: &dyn DefDatabase) -> Option<CrateId> {
+        Some(match self {
+            ItemInNs::Types(did) | ItemInNs::Values(did) => match did {
+                ModuleDefId::ModuleId(id) => id.krate,
+                ModuleDefId::FunctionId(id) => id.lookup(db).module(db).krate,
+                ModuleDefId::AdtId(id) => id.module(db).krate,
+                ModuleDefId::EnumVariantId(id) => id.parent.lookup(db).container.module(db).krate,
+                ModuleDefId::ConstId(id) => id.lookup(db).container.module(db).krate,
+                ModuleDefId::StaticId(id) => id.lookup(db).container.module(db).krate,
+                ModuleDefId::TraitId(id) => id.lookup(db).container.module(db).krate,
+                ModuleDefId::TypeAliasId(id) => id.lookup(db).module(db).krate,
+                ModuleDefId::BuiltinType(_) => return None,
+            },
+            ItemInNs::Macros(id) => return id.krate,
+        })
+    }
 }
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index 5325a2760..edc59e5a8 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -43,6 +43,7 @@ pub mod child_by_source;
 
 pub mod visibility;
 pub mod find_path;
+pub mod import_map;
 
 #[cfg(test)]
 mod test_db;
@@ -416,6 +417,7 @@ pub trait AsMacroCall {
     fn as_call_id(
         &self,
         db: &dyn db::DefDatabase,
+        krate: CrateId,
         resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
     ) -> Option<MacroCallId>;
 }
@@ -424,13 +426,14 @@ impl AsMacroCall for InFile<&ast::MacroCall> {
     fn as_call_id(
         &self,
         db: &dyn db::DefDatabase,
+        krate: CrateId,
         resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
     ) -> Option<MacroCallId> {
         let ast_id = AstId::new(self.file_id, db.ast_id_map(self.file_id).ast_id(self.value));
         let h = Hygiene::new(db.upcast(), self.file_id);
         let path = path::ModPath::from_src(self.value.path()?, &h)?;
 
-        AstIdWithPath::new(ast_id.file_id, ast_id.value, path).as_call_id(db, resolver)
+        AstIdWithPath::new(ast_id.file_id, ast_id.value, path).as_call_id(db, krate, resolver)
     }
 }
 
@@ -451,6 +454,7 @@ impl AsMacroCall for AstIdWithPath<ast::MacroCall> {
     fn as_call_id(
         &self,
         db: &dyn db::DefDatabase,
+        krate: CrateId,
         resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
     ) -> Option<MacroCallId> {
         let def: MacroDefId = resolver(self.path.clone())?;
@@ -460,13 +464,13 @@ impl AsMacroCall for AstIdWithPath<ast::MacroCall> {
             let hygiene = Hygiene::new(db.upcast(), self.ast_id.file_id);
 
             Some(
-                expand_eager_macro(db.upcast(), macro_call, def, &|path: ast::Path| {
+                expand_eager_macro(db.upcast(), krate, macro_call, def, &|path: ast::Path| {
                     resolver(path::ModPath::from_src(path, &hygiene)?)
                 })?
                 .into(),
             )
         } else {
-            Some(def.as_lazy_macro(db.upcast(), MacroCallKind::FnLike(self.ast_id)).into())
+            Some(def.as_lazy_macro(db.upcast(), krate, MacroCallKind::FnLike(self.ast_id)).into())
         }
     }
 }
@@ -475,12 +479,14 @@ impl AsMacroCall for AstIdWithPath<ast::ModuleItem> {
     fn as_call_id(
         &self,
         db: &dyn db::DefDatabase,
+        krate: CrateId,
         resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
     ) -> Option<MacroCallId> {
         let def = resolver(self.path.clone())?;
         Some(
             def.as_lazy_macro(
                 db.upcast(),
+                krate,
                 MacroCallKind::Attr(self.ast_id, self.path.segments.last()?.to_string()),
             )
             .into(),
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index 353a31ad4..976e5e585 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -571,16 +571,18 @@ impl DefCollector<'_> {
                 return false;
             }
 
-            if let Some(call_id) = directive.ast_id.as_call_id(self.db, |path| {
-                let resolved_res = self.def_map.resolve_path_fp_with_macro(
-                    self.db,
-                    ResolveMode::Other,
-                    directive.module_id,
-                    &path,
-                    BuiltinShadowMode::Module,
-                );
-                resolved_res.resolved_def.take_macros()
-            }) {
+            if let Some(call_id) =
+                directive.ast_id.as_call_id(self.db, self.def_map.krate, |path| {
+                    let resolved_res = self.def_map.resolve_path_fp_with_macro(
+                        self.db,
+                        ResolveMode::Other,
+                        directive.module_id,
+                        &path,
+                        BuiltinShadowMode::Module,
+                    );
+                    resolved_res.resolved_def.take_macros()
+                })
+            {
                 resolved.push((directive.module_id, call_id, directive.depth));
                 res = ReachedFixedPoint::No;
                 return false;
@@ -589,9 +591,10 @@ impl DefCollector<'_> {
             true
         });
         attribute_macros.retain(|directive| {
-            if let Some(call_id) = directive
-                .ast_id
-                .as_call_id(self.db, |path| self.resolve_attribute_macro(&directive, &path))
+            if let Some(call_id) =
+                directive.ast_id.as_call_id(self.db, self.def_map.krate, |path| {
+                    self.resolve_attribute_macro(&directive, &path)
+                })
             {
                 resolved.push((directive.module_id, call_id, 0));
                 res = ReachedFixedPoint::No;
@@ -957,11 +960,13 @@ impl ModCollector<'_, '_> {
         }
 
         // Case 2: try to resolve in legacy scope and expand macro_rules
-        if let Some(macro_call_id) = ast_id.as_call_id(self.def_collector.db, |path| {
-            path.as_ident().and_then(|name| {
-                self.def_collector.def_map[self.module_id].scope.get_legacy_macro(&name)
+        if let Some(macro_call_id) =
+            ast_id.as_call_id(self.def_collector.db, self.def_collector.def_map.krate, |path| {
+                path.as_ident().and_then(|name| {
+                    self.def_collector.def_map[self.module_id].scope.get_legacy_macro(&name)
+                })
             })
-        }) {
+        {
             self.def_collector.unexpanded_macros.push(MacroDirective {
                 module_id: self.module_id,
                 ast_id,
diff --git a/crates/ra_hir_def/src/nameres/mod_resolution.rs b/crates/ra_hir_def/src/nameres/mod_resolution.rs
index 386c5cade..cede4a6fc 100644
--- a/crates/ra_hir_def/src/nameres/mod_resolution.rs
+++ b/crates/ra_hir_def/src/nameres/mod_resolution.rs
@@ -61,7 +61,7 @@ impl ModDir {
         };
 
         for candidate in candidate_files.iter() {
-            if let Some(file_id) = db.resolve_relative_path(file_id, candidate) {
+            if let Some(file_id) = db.resolve_path(file_id, candidate.as_str()) {
                 let mut root_non_dir_owner = false;
                 let mut mod_path = RelativePathBuf::new();
                 if !(candidate.ends_with("mod.rs") || attr_path.is_some()) {
diff --git a/crates/ra_hir_def/src/path.rs b/crates/ra_hir_def/src/path.rs
index e84efe2ab..ba16442bd 100644
--- a/crates/ra_hir_def/src/path.rs
+++ b/crates/ra_hir_def/src/path.rs
@@ -76,6 +76,19 @@ impl ModPath {
         }
     }
 
+    /// Returns the number of segments in the path (counting special segments like `$crate` and
+    /// `super`).
+    pub fn len(&self) -> usize {
+        self.segments.len()
+            + match self.kind {
+                PathKind::Plain => 0,
+                PathKind::Super(i) => i as usize,
+                PathKind::Crate => 1,
+                PathKind::Abs => 0,
+                PathKind::DollarCrate(_) => 1,
+            }
+    }
+
     pub fn is_ident(&self) -> bool {
         self.kind == PathKind::Plain && self.segments.len() == 1
     }
@@ -273,7 +286,7 @@ impl From<Name> for ModPath {
 impl Display for ModPath {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut first_segment = true;
-        let mut add_segment = |s| {
+        let mut add_segment = |s| -> fmt::Result {
             if !first_segment {
                 f.write_str("::")?;
             }
@@ -310,16 +323,16 @@ pub use hir_expand::name as __name;
 
 #[macro_export]
 macro_rules! __known_path {
-    (std::iter::IntoIterator) => {};
-    (std::result::Result) => {};
-    (std::ops::Range) => {};
-    (std::ops::RangeFrom) => {};
-    (std::ops::RangeFull) => {};
-    (std::ops::RangeTo) => {};
-    (std::ops::RangeToInclusive) => {};
-    (std::ops::RangeInclusive) => {};
-    (std::future::Future) => {};
-    (std::ops::Try) => {};
+    (core::iter::IntoIterator) => {};
+    (core::result::Result) => {};
+    (core::ops::Range) => {};
+    (core::ops::RangeFrom) => {};
+    (core::ops::RangeFull) => {};
+    (core::ops::RangeTo) => {};
+    (core::ops::RangeToInclusive) => {};
+    (core::ops::RangeInclusive) => {};
+    (core::future::Future) => {};
+    (core::ops::Try) => {};
     ($path:path) => {
         compile_error!("Please register your known path in the path module")
     };
diff --git a/crates/ra_hir_def/src/per_ns.rs b/crates/ra_hir_def/src/per_ns.rs
index 6e435c8c1..74665c588 100644
--- a/crates/ra_hir_def/src/per_ns.rs
+++ b/crates/ra_hir_def/src/per_ns.rs
@@ -5,7 +5,7 @@
 
 use hir_expand::MacroDefId;
 
-use crate::{visibility::Visibility, ModuleDefId};
+use crate::{item_scope::ItemInNs, visibility::Visibility, ModuleDefId};
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub struct PerNs {
@@ -84,4 +84,12 @@ impl PerNs {
             macros: self.macros.or(other.macros),
         }
     }
+
+    pub fn iter_items(self) -> impl Iterator<Item = ItemInNs> {
+        self.types
+            .map(|it| ItemInNs::Types(it.0))
+            .into_iter()
+            .chain(self.values.map(|it| ItemInNs::Values(it.0)).into_iter())
+            .chain(self.macros.map(|it| ItemInNs::Macros(it.0)).into_iter())
+    }
 }
diff --git a/crates/ra_hir_def/src/test_db.rs b/crates/ra_hir_def/src/test_db.rs
index eb83dee79..4581d8745 100644
--- a/crates/ra_hir_def/src/test_db.rs
+++ b/crates/ra_hir_def/src/test_db.rs
@@ -6,9 +6,8 @@ use std::{
 };
 
 use hir_expand::db::AstDatabase;
-use ra_db::{
-    salsa, CrateId, ExternSourceId, FileId, FileLoader, FileLoaderDelegate, RelativePath, Upcast,
-};
+use ra_db::{salsa, CrateId, FileId, FileLoader, FileLoaderDelegate, Upcast};
+use rustc_hash::FxHashSet;
 
 use crate::db::DefDatabase;
 
@@ -58,24 +57,12 @@ impl FileLoader for TestDB {
     fn file_text(&self, file_id: FileId) -> Arc<String> {
         FileLoaderDelegate(self).file_text(file_id)
     }
-    fn resolve_relative_path(
-        &self,
-        anchor: FileId,
-        relative_path: &RelativePath,
-    ) -> Option<FileId> {
-        FileLoaderDelegate(self).resolve_relative_path(anchor, relative_path)
+    fn resolve_path(&self, anchor: FileId, path: &str) -> Option<FileId> {
+        FileLoaderDelegate(self).resolve_path(anchor, path)
     }
-    fn relevant_crates(&self, file_id: FileId) -> Arc<Vec<CrateId>> {
+    fn relevant_crates(&self, file_id: FileId) -> Arc<FxHashSet<CrateId>> {
         FileLoaderDelegate(self).relevant_crates(file_id)
     }
-
-    fn resolve_extern_path(
-        &self,
-        extern_id: ExternSourceId,
-        relative_path: &RelativePath,
-    ) -> Option<FileId> {
-        FileLoaderDelegate(self).resolve_extern_path(extern_id, relative_path)
-    }
 }
 
 impl TestDB {
diff --git a/crates/ra_hir_expand/Cargo.toml b/crates/ra_hir_expand/Cargo.toml
index 2cd522766..e5c9f3e99 100644
--- a/crates/ra_hir_expand/Cargo.toml
+++ b/crates/ra_hir_expand/Cargo.toml
@@ -10,6 +10,7 @@ doctest = false
 [dependencies]
 log = "0.4.8"
 either = "1.5.3"
+rustc-hash = "1.0.0"
 
 ra_arena = { path = "../ra_arena" }
 ra_db = { path = "../ra_db" }
diff --git a/crates/ra_hir_expand/src/builtin_derive.rs b/crates/ra_hir_expand/src/builtin_derive.rs
index 1dc9cac66..26b667b55 100644
--- a/crates/ra_hir_expand/src/builtin_derive.rs
+++ b/crates/ra_hir_expand/src/builtin_derive.rs
@@ -8,8 +8,7 @@ use ra_syntax::{
     match_ast,
 };
 
-use crate::db::AstDatabase;
-use crate::{name, quote, LazyMacroId, MacroCallId, MacroDefId, MacroDefKind};
+use crate::{db::AstDatabase, name, quote, LazyMacroId, MacroDefId, MacroDefKind};
 
 macro_rules! register_builtin {
     ( $($trait:ident => $expand:ident),* ) => {
@@ -156,23 +155,13 @@ fn expand_simple_derive(
 fn find_builtin_crate(db: &dyn AstDatabase, id: LazyMacroId) -> tt::TokenTree {
     // FIXME: make hygiene works for builtin derive macro
     // such that $crate can be used here.
-
-    let m: MacroCallId = id.into();
-    let file_id = m.as_file().original_file(db);
     let cg = db.crate_graph();
-    let krates = db.relevant_crates(file_id);
-    let krate = match krates.get(0) {
-        Some(krate) => krate,
-        None => {
-            let tt = quote! { core };
-            return tt.token_trees[0].clone();
-        }
-    };
+    let krate = db.lookup_intern_macro(id).krate;
 
     // XXX
     //  All crates except core itself should have a dependency on core,
     //  We detect `core` by seeing whether it doesn't have such a dependency.
-    let tt = if cg[*krate].dependencies.iter().any(|dep| dep.name == "core") {
+    let tt = if cg[krate].dependencies.iter().any(|dep| dep.name == "core") {
         quote! { core }
     } else {
         quote! { crate }
@@ -264,10 +253,12 @@ fn partial_ord_expand(
 
 #[cfg(test)]
 mod tests {
-    use super::*;
-    use crate::{test_db::TestDB, AstId, MacroCallId, MacroCallKind, MacroCallLoc};
     use name::{known, Name};
-    use ra_db::{fixture::WithFixture, SourceDatabase};
+    use ra_db::{fixture::WithFixture, CrateId, SourceDatabase};
+
+    use crate::{test_db::TestDB, AstId, MacroCallId, MacroCallKind, MacroCallLoc};
+
+    use super::*;
 
     fn expand_builtin_derive(s: &str, name: Name) -> String {
         let def = find_builtin_derive(&name).unwrap();
@@ -291,7 +282,11 @@ mod tests {
 
         let attr_id = AstId::new(file_id.into(), ast_id_map.ast_id(&items[0]));
 
-        let loc = MacroCallLoc { def, kind: MacroCallKind::Attr(attr_id, name.to_string()) };
+        let loc = MacroCallLoc {
+            def,
+            krate: CrateId(0),
+            kind: MacroCallKind::Attr(attr_id, name.to_string()),
+        };
 
         let id: MacroCallId = db.intern_macro(loc).into();
         let parsed = db.parse_or_expand(id.as_file()).unwrap();
diff --git a/crates/ra_hir_expand/src/builtin_macro.rs b/crates/ra_hir_expand/src/builtin_macro.rs
index 3bce8f673..b50eb347c 100644
--- a/crates/ra_hir_expand/src/builtin_macro.rs
+++ b/crates/ra_hir_expand/src/builtin_macro.rs
@@ -1,15 +1,14 @@
 //! Builtin macro
-use crate::db::AstDatabase;
 use crate::{
-    ast::{self, AstToken, HasStringValue},
-    name, AstId, CrateId, MacroDefId, MacroDefKind, TextSize,
+    db::AstDatabase, name, quote, AstId, CrateId, EagerMacroId, LazyMacroId, MacroCallId,
+    MacroDefId, MacroDefKind, TextSize,
 };
 
-use crate::{quote, EagerMacroId, LazyMacroId, MacroCallId};
 use either::Either;
 use mbe::parse_to_token_tree;
-use ra_db::{FileId, RelativePath};
+use ra_db::FileId;
 use ra_parser::FragmentKind;
+use ra_syntax::ast::{self, AstToken, HasStringValue};
 
 macro_rules! register_builtin {
     ( LAZY: $(($name:ident, $kind: ident) => $expand:ident),* , EAGER: $(($e_name:ident, $e_kind: ident) => $e_expand:ident),*  ) => {
@@ -295,19 +294,13 @@ fn concat_expand(
 
 fn relative_file(db: &dyn AstDatabase, call_id: MacroCallId, path: &str) -> Option<FileId> {
     let call_site = call_id.as_file().original_file(db);
-
-    // Handle trivial case
-    if let Some(res) = db.resolve_relative_path(call_site, &RelativePath::new(&path)) {
-        // Prevent include itself
-        return if res == call_site { None } else { Some(res) };
+    let res = db.resolve_path(call_site, path)?;
+    // Prevent include itself
+    if res == call_site {
+        None
+    } else {
+        Some(res)
     }
-
-    // Extern paths ?
-    let krate = *db.relevant_crates(call_site).get(0)?;
-    let (extern_source_id, relative_file) =
-        db.crate_graph()[krate].extern_source.extern_path(path)?;
-
-    db.resolve_extern_path(extern_source_id, &relative_file)
 }
 
 fn parse_string(tt: &tt::Subtree) -> Result<String, mbe::ExpandError> {
@@ -339,10 +332,7 @@ fn include_expand(
 }
 
 fn get_env_inner(db: &dyn AstDatabase, arg_id: EagerMacroId, key: &str) -> Option<String> {
-    let call_id: MacroCallId = arg_id.into();
-    let original_file = call_id.as_file().original_file(db);
-
-    let krate = *db.relevant_crates(original_file).get(0)?;
+    let krate = db.lookup_intern_eager_expansion(arg_id).krate;
     db.crate_graph()[krate].env.get(key)
 }
 
@@ -401,6 +391,7 @@ mod tests {
 
         let expander = find_by_name(&macro_calls[0].name().unwrap().as_name()).unwrap();
 
+        let krate = CrateId(0);
         let file_id = match expander {
             Either::Left(expander) => {
                 // the first one should be a macro_rules
@@ -413,6 +404,7 @@ mod tests {
 
                 let loc = MacroCallLoc {
                     def,
+                    krate,
                     kind: MacroCallKind::FnLike(AstId::new(
                         file_id.into(),
                         ast_id_map.ast_id(&macro_calls[1]),
@@ -425,7 +417,7 @@ mod tests {
             Either::Right(expander) => {
                 // the first one should be a macro_rules
                 let def = MacroDefId {
-                    krate: Some(CrateId(0)),
+                    krate: Some(krate),
                     ast_id: Some(AstId::new(file_id.into(), ast_id_map.ast_id(&macro_calls[0]))),
                     kind: MacroDefKind::BuiltInEager(expander),
                     local_inner: false,
@@ -439,6 +431,7 @@ mod tests {
                         def,
                         fragment: FragmentKind::Expr,
                         subtree: Arc::new(parsed_args.clone()),
+                        krate,
                         file_id: file_id.into(),
                     }
                 });
@@ -448,6 +441,7 @@ mod tests {
                     def,
                     fragment,