12 files changed, 226 insertions, 88 deletions

diff --git a/crates/hir_def/src/nameres/tests/incremental.rs b/crates/hir_def/src/nameres/tests/incremental.rs
index d884a6eb4..7bf152e26 100644
--- a/crates/hir_def/src/nameres/tests/incremental.rs
+++ b/crates/hir_def/src/nameres/tests/incremental.rs
@@ -1,6 +1,8 @@
 use std::sync::Arc;
 
-use base_db::SourceDatabaseExt;
+use base_db::{salsa::SweepStrategy, SourceDatabaseExt};
+
+use crate::{AdtId, ModuleDefId};
 
 use super::*;
 
@@ -163,3 +165,73 @@ m!(Z);
         assert_eq!(n_reparsed_macros, 0);
     }
 }
+
+#[test]
+fn item_tree_prevents_reparsing() {
+    // The `ItemTree` is used by both name resolution and the various queries in `adt.rs` and
+    // `data.rs`. After computing the `ItemTree` and deleting the parse tree, we should be able to
+    // run those other queries without triggering a reparse.
+
+    let (db, pos) = TestDB::with_position(
+        r#"
+pub struct S;
+pub union U {}
+pub enum E {
+    Variant,
+}
+pub fn f(_: S) { $0 }
+pub trait Tr {}
+impl Tr for () {}
+pub const C: u8 = 0;
+pub static ST: u8 = 0;
+pub type Ty = ();
+"#,
+    );
+    let krate = db.test_crate();
+    {
+        let events = db.log_executed(|| {
+            db.file_item_tree(pos.file_id.into());
+        });
+        let n_calculated_item_trees = events.iter().filter(|it| it.contains("item_tree")).count();
+        assert_eq!(n_calculated_item_trees, 1);
+        let n_parsed_files = events.iter().filter(|it| it.contains("parse(")).count();
+        assert_eq!(n_parsed_files, 1);
+    }
+
+    // Delete the parse tree.
+    let sweep = SweepStrategy::default().discard_values().sweep_all_revisions();
+    base_db::ParseQuery.in_db(&db).sweep(sweep);
+
+    {
+        let events = db.log_executed(|| {
+            let crate_def_map = db.crate_def_map(krate);
+            let (_, module_data) = crate_def_map.modules.iter().last().unwrap();
+            assert_eq!(module_data.scope.resolutions().count(), 8);
+            assert_eq!(module_data.scope.impls().count(), 1);
+
+            for imp in module_data.scope.impls() {
+                db.impl_data(imp);
+            }
+
+            for (_, res) in module_data.scope.resolutions() {
+                match res.values.or(res.types).unwrap().0 {
+                    ModuleDefId::FunctionId(f) => drop(db.function_data(f)),
+                    ModuleDefId::AdtId(adt) => match adt {
+                        AdtId::StructId(it) => drop(db.struct_data(it)),
+                        AdtId::UnionId(it) => drop(db.union_data(it)),
+                        AdtId::EnumId(it) => drop(db.enum_data(it)),
+                    },
+                    ModuleDefId::ConstId(it) => drop(db.const_data(it)),
+                    ModuleDefId::StaticId(it) => drop(db.static_data(it)),
+                    ModuleDefId::TraitId(it) => drop(db.trait_data(it)),
+                    ModuleDefId::TypeAliasId(it) => drop(db.type_alias_data(it)),
+                    ModuleDefId::EnumVariantId(_)
+                    | ModuleDefId::ModuleId(_)
+                    | ModuleDefId::BuiltinType(_) => unreachable!(),
+                }
+            }
+        });
+        let n_reparsed_files = events.iter().filter(|it| it.contains("parse(")).count();
+        assert_eq!(n_reparsed_files, 0);
+    }
+}
diff --git a/crates/hir_ty/src/tests.rs b/crates/hir_ty/src/tests.rs
index cc819373c..9d726b024 100644
--- a/crates/hir_ty/src/tests.rs
+++ b/crates/hir_ty/src/tests.rs
@@ -7,6 +7,7 @@ mod traits;
 mod method_resolution;
 mod macros;
 mod display_source_code;
+mod incremental;
 
 use std::{env, sync::Arc};
 
@@ -317,50 +318,6 @@ fn ellipsize(mut text: String, max_len: usize) -> String {
     text
 }
 
-#[test]
-fn typing_whitespace_inside_a_function_should_not_invalidate_types() {
-    let (mut db, pos) = TestDB::with_position(
-        "
-        //- /lib.rs
-        fn foo() -> i32 {
-            $01 + 1
-        }
-    ",
-    );
-    {
-        let events = db.log_executed(|| {
-            let module = db.module_for_file(pos.file_id);
-            let crate_def_map = module.def_map(&db);
-            visit_module(&db, &crate_def_map, module.local_id, &mut |def| {
-                db.infer(def);
-            });
-        });
-        assert!(format!("{:?}", events).contains("infer"))
-    }
-
-    let new_text = "
-        fn foo() -> i32 {
-            1
-            +
-            1
-        }
-    "
-    .to_string();
-
-    db.set_file_text(pos.file_id, Arc::new(new_text));
-
-    {
-        let events = db.log_executed(|| {
-            let module = db.module_for_file(pos.file_id);
-            let crate_def_map = module.def_map(&db);
-            visit_module(&db, &crate_def_map, module.local_id, &mut |def| {
-                db.infer(def);
-            });
-        });
-        assert!(!format!("{:?}", events).contains("infer"), "{:#?}", events)
-    }
-}
-
 fn check_infer(ra_fixture: &str, expect: Expect) {
     let mut actual = infer(ra_fixture);
     actual.push('\n');
diff --git a/crates/hir_ty/src/tests/incremental.rs b/crates/hir_ty/src/tests/incremental.rs
new file mode 100644
index 000000000..3e08e83e8
--- /dev/null
+++ b/crates/hir_ty/src/tests/incremental.rs
@@ -0,0 +1,51 @@
+use std::sync::Arc;
+
+use base_db::{fixture::WithFixture, SourceDatabaseExt};
+
+use crate::{db::HirDatabase, test_db::TestDB};
+
+use super::visit_module;
+
+#[test]
+fn typing_whitespace_inside_a_function_should_not_invalidate_types() {
+    let (mut db, pos) = TestDB::with_position(
+        "
+        //- /lib.rs
+        fn foo() -> i32 {
+            $01 + 1
+        }
+    ",
+    );
+    {
+        let events = db.log_executed(|| {
+            let module = db.module_for_file(pos.file_id);
+            let crate_def_map = module.def_map(&db);
+            visit_module(&db, &crate_def_map, module.local_id, &mut |def| {
+                db.infer(def);
+            });
+        });
+        assert!(format!("{:?}", events).contains("infer"))
+    }
+
+    let new_text = "
+        fn foo() -> i32 {
+            1
+            +
+            1
+        }
+    "
+    .to_string();
+
+    db.set_file_text(pos.file_id, Arc::new(new_text));
+
+    {
+        let events = db.log_executed(|| {
+            let module = db.module_for_file(pos.file_id);
+            let crate_def_map = module.def_map(&db);
+            visit_module(&db, &crate_def_map, module.local_id, &mut |def| {
+                db.infer(def);
+            });
+        });
+        assert!(!format!("{:?}", events).contains("infer"), "{:#?}", events)
+    }
+}
diff --git a/crates/ide/src/annotations.rs b/crates/ide/src/annotations.rs
index b0c4ed60a..8d68dce05 100644
--- a/crates/ide/src/annotations.rs
+++ b/crates/ide/src/annotations.rs
@@ -58,7 +58,7 @@ pub(crate) fn annotations(
             }
 
             let action = runnable.action();
-            let range = runnable.nav.full_range;
+            let range = runnable.nav.focus_or_full_range();
 
             if config.run {
                 annotations.push(Annotation {
@@ -224,7 +224,7 @@ fn main() {
             expect![[r#"
                 [
                     Annotation {
-                        range: 50..85,
+                        range: 53..57,
                         kind: Runnable {
                             debug: false,
                             runnable: Runnable {
@@ -243,7 +243,7 @@ fn main() {
                         },
                     },
                     Annotation {
-                        range: 50..85,
+                        range: 53..57,
                         kind: Runnable {
                             debug: true,
                             runnable: Runnable {
@@ -328,7 +328,7 @@ fn main() {
             expect![[r#"
                 [
                     Annotation {
-                        range: 14..48,
+                        range: 17..21,
                         kind: Runnable {
                             debug: false,
                             runnable: Runnable {
@@ -347,7 +347,7 @@ fn main() {
                         },
                     },
                     Annotation {
-                        range: 14..48,
+                        range: 17..21,
                         kind: Runnable {
                             debug: true,
                             runnable: Runnable {
@@ -436,7 +436,7 @@ fn main() {
             expect![[r#"
                 [
                     Annotation {
-                        range: 66..100,
+                        range: 69..73,
                         kind: Runnable {
                             debug: false,
                             runnable: Runnable {
@@ -455,7 +455,7 @@ fn main() {
                         },
                     },
                     Annotation {
-                        range: 66..100,
+                        range: 69..73,
                         kind: Runnable {
                             debug: true,
                             runnable: Runnable {
@@ -597,7 +597,7 @@ fn main() {}
             expect![[r#"
                 [
                     Annotation {
-                        range: 0..12,
+                        range: 3..7,
                         kind: Runnable {
                             debug: false,
                             runnable: Runnable {
@@ -616,7 +616,7 @@ fn main() {}
                         },
                     },
                     Annotation {
-                        range: 0..12,
+                        range: 3..7,
                         kind: Runnable {
                             debug: true,
                             runnable: Runnable {
@@ -670,7 +670,7 @@ fn main() {
             expect![[r#"
                 [
                     Annotation {
-                        range: 58..95,
+                        range: 61..65,
                         kind: Runnable {
                             debug: false,
                             runnable: Runnable {
@@ -689,7 +689,7 @@ fn main() {
                         },
                     },
                     Annotation {
-                        range: 58..95,
+                        range: 61..65,
                         kind: Runnable {
                             debug: true,
                             runnable: Runnable {
@@ -812,7 +812,7 @@ mod tests {
             expect![[r#"
                 [
                     Annotation {
-                        range: 0..12,
+                        range: 3..7,
                         kind: Runnable {
                             debug: false,
                             runnable: Runnable {
@@ -831,7 +831,7 @@ mod tests {
                         },
                     },
                     Annotation {
-                        range: 0..12,
+                        range: 3..7,
                         kind: Runnable {
                             debug: true,
                             runnable: Runnable {
@@ -850,7 +850,7 @@ mod tests {
                         },
                     },
                     Annotation {
-                        range: 14..64,
+                        range: 18..23,
                         kind: Runnable {
                             debug: false,
                             runnable: Runnable {
@@ -871,7 +871,7 @@ mod tests {
                         },
                     },
                     Annotation {
-                        range: 14..64,
+                        range: 18..23,
                         kind: Runnable {
                             debug: true,
                             runnable: Runnable {
@@ -892,7 +892,7 @@ mod tests {
                         },
                     },
                     Annotation {
-                        range: 30..62,
+                        range: 45..57,
                         kind: Runnable {
                             debug: false,
                             runnable: Runnable {
@@ -918,7 +918,7 @@ mod tests {
                         },
                     },
                     Annotation {
-                        range: 30..62,
+                        range: 45..57,
                         kind: Runnable {
                             debug: true,
                             runnable: Runnable {
diff --git a/crates/ide/src/folding_ranges.rs b/crates/ide/src/folding_ranges.rs
index b893c1c54..c5015a345 100755
--- a/crates/ide/src/folding_ranges.rs
+++ b/crates/ide/src/folding_ranges.rs
@@ -19,6 +19,7 @@ pub enum FoldKind {
     Statics,
     Array,
     WhereClause,
+    ReturnType,
 }
 
 #[derive(Debug)]
@@ -131,6 +132,7 @@ fn fold_kind(kind: SyntaxKind) -> Option<FoldKind> {
         COMMENT => Some(FoldKind::Comment),
         ARG_LIST | PARAM_LIST => Some(FoldKind::ArgList),
         ARRAY_EXPR => Some(FoldKind::Array),
+        RET_TYPE => Some(FoldKind::ReturnType),
         ASSOC_ITEM_LIST
         | RECORD_FIELD_LIST
         | RECORD_PAT_FIELD_LIST
@@ -300,6 +302,7 @@ mod tests {
                 FoldKind::Statics => "statics",
                 FoldKind::Array => "array",
                 FoldKind::WhereClause => "whereclause",
+                FoldKind::ReturnType => "returntype",
             };
             assert_eq!(kind, &attr.unwrap());
         }
@@ -560,4 +563,18 @@ where
 "#,
         )
     }
+
+    #[test]
+    fn fold_return_type() {
+        check(
+            r#"
+fn foo()<fold returntype>-> (
+    bool,
+    bool,
+)</fold> { (true, true) }
+
+fn bar() -> (bool, bool) { (true, true) }
+            "#,
+        )
+    }
 }
diff --git a/crates/ide_completion/src/completions/keyword.rs b/crates/ide_completion/src/completions/keyword.rs
index 96447a603..c9673df85 100644
--- a/crates/ide_completion/src/completions/keyword.rs
+++ b/crates/ide_completion/src/completions/keyword.rs
@@ -395,6 +395,21 @@ fn quux() -> i32 {
     }
 
     #[test]
+    fn test_keywords_in_impl_def_with_attr() {
+        check(
+            r"impl My { #[foo] $0 }",
+            expect![[r#"
+                kw fn
+                kw const
+                kw type
+                kw unsafe
+                kw pub(crate)
+                kw pub
+            "#]],
+        );
+    }
+
+    #[test]
     fn test_keywords_in_loop() {
         check(
             r"fn my() { loop { $0 } }",
diff --git a/crates/ide_completion/src/completions/unqualified_path.rs b/crates/ide_completion/src/completions/unqualified_path.rs
index c901b358b..ede07f605 100644
--- a/crates/ide_completion/src/completions/unqualified_path.rs
+++ b/crates/ide_completion/src/completions/unqualified_path.rs
@@ -1,7 +1,6 @@
 //! Completion of names from the current scope, e.g. locals and imported items.
 
 use hir::ScopeDef;
-use syntax::AstNode;
 
 use crate::{CompletionContext, Completions};
 
@@ -24,6 +23,15 @@ pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
         return;
     }
 
+    if ctx.expects_use_tree() {
+        cov_mark::hit!(only_completes_modules_in_import);
+        ctx.scope.process_all_names(&mut |name, res| {
+            if let ScopeDef::ModuleDef(hir::ModuleDef::Module(_)) = res {
+                acc.add_resolution(ctx, name.to_string(), &res);
+            }
+        });
+        return;
+    }
     if let Some(hir::Adt::Enum(e)) =
         ctx.expected_type.as_ref().and_then(|ty| ty.strip_references().as_adt())
     {
@@ -37,14 +45,6 @@ pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
             cov_mark::hit!(skip_lifetime_completion);
             return;
         }
-        if ctx.use_item_syntax.is_some() {
-            if let (ScopeDef::Unknown, Some(name_ref)) = (&res, &ctx.name_ref_syntax) {
-                if name_ref.syntax().text() == name.to_string().as_str() {
-                    cov_mark::hit!(self_fulfilling_completion);
-                    return;
-                }
-            }
-        }
         acc.add_resolution(ctx, name.to_string(), &res);
     });
 }
@@ -68,15 +68,17 @@ mod tests {
     }
 
     #[test]
-    fn self_fulfilling_completion() {
-        cov_mark::check!(self_fulfilling_completion);
+    fn only_completes_modules_in_import() {
+        cov_mark::check!(only_completes_modules_in_import);
         check(
             r#"
-use foo$0
-use std::collections;
+use f$0
+
+struct Foo;
+mod foo {}
 "#,
             expect![[r#"
-                ?? collections
+                md foo
             "#]],
         );
     }
diff --git a/crates/ide_completion/src/context.rs b/crates/ide_completion/src/context.rs
index fbef54408..923e35dbb 100644
--- a/crates/ide_completion/src/context.rs
+++ b/crates/ide_completion/src/context.rs
@@ -276,6 +276,10 @@ impl<'a> CompletionContext<'a> {
         )
     }
 
+    pub(crate) fn expects_use_tree(&self) -> bool {
+        matches!(self.completion_location, Some(ImmediateLocation::Use))
+    }
+
     pub(crate) fn expects_non_trait_assoc_item(&self) -> bool {
         matches!(self.completion_location, Some(ImmediateLocation::Impl))
     }
diff --git a/crates/ide_completion/src/patterns.rs b/crates/ide_completion/src/patterns.rs
index 19e42ba43..c8a88367d 100644
--- a/crates/ide_completion/src/patterns.rs
+++ b/crates/ide_completion/src/patterns.rs
@@ -14,6 +14,7 @@ use crate::test_utils::{check_pattern_is_applicable, check_pattern_is_not_applic
 /// Direct parent container of the cursor position
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub(crate) enum ImmediateLocation {
+    Use,
     Impl,
     Trait,
     RecordField,
@@ -24,9 +25,10 @@ pub(crate) enum ImmediateLocation {
 }
 
 pub(crate) fn determine_location(tok: SyntaxToken) -> Option<ImmediateLocation> {
-    // First "expand" the element we are completing to its maximum so that we can check in what
-    // context it immediately lies. This for example means if the token is a NameRef at the end of
-    // a path, we want to look at where the path is in the tree.
+    // First walk the element we are completing up to its highest node that has the same text range
+    // as the element so that we can check in what context it immediately lies. We only do this for
+    // NameRef -> Path as that's the only thing that makes sense to being "expanded" semantically.
+    // We only wanna do this if the NameRef is the last segment of the path.
     let node = match tok.parent().and_then(ast::NameLike::cast)? {
         ast::NameLike::NameRef(name_ref) => {
             if let Some(segment) = name_ref.syntax().parent().and_then(ast::PathSegment::cast) {
@@ -46,7 +48,20 @@ pub(crate) fn determine_location(tok: SyntaxToken) -> Option<ImmediateLocation>
         it @ ast::NameLike::Name(_) | it @ ast::NameLike::Lifetime(_) => it.syntax().clone(),
     };
     let parent = match node.parent() {
-        Some(parent) => parent,
+        Some(parent) => match ast::MacroCall::cast(parent.clone()) {
+            // When a path is being typed in an (Assoc)ItemList the parser will always emit a macro_call.
+            // This is usually fine as the node expansion code above already accounts for that with
+            // the ancestors call, but there is one exception to this which is that when an attribute
+            // precedes it the code above will not walk the Path to the parent MacroCall as their ranges differ.
+            Some(call)
+                if call.excl_token().is_none()
+                    && call.token_tree().is_none()
+                    && call.semicolon_token().is_none() =>
+            {
+                call.syntax().parent()?
+            }
+            _ => parent,
+        },
         // SourceFile
         None => {
             return match node.kind() {
@@ -58,6 +73,7 @@ pub(crate) fn determine_location(tok: SyntaxToken) -> Option<ImmediateLocation>
     let res = match_ast! {
         match parent {
             ast::IdentPat(_it) => ImmediateLocation::IdentPat,
+            ast::Use(_it) => ImmediateLocation::Use,
             ast::BlockExpr(_it) => ImmediateLocation::BlockExpr,
             ast::SourceFile(_it) => ImmediateLocation::ItemList,
             ast::ItemList(_it) => ImmediateLocation::ItemList,
@@ -88,6 +104,11 @@ fn test_has_trait_parent() {
 }
 
 #[test]
+fn test_has_use_parent() {
+    check_location(r"use f$0", ImmediateLocation::Use);
+}
+
+#[test]
 fn test_has_impl_parent() {
     check_location(r"impl A { f$0 }", ImmediateLocation::Impl);
 }
diff --git a/crates/ide_completion/src/render/macro_.rs b/crates/ide_completion/src/render/macro_.rs
index 7578ad50b..b90fd3890 100644
--- a/crates/ide_completion/src/render/macro_.rs
+++ b/crates/ide_completion/src/render/macro_.rs
@@ -74,7 +74,11 @@ impl<'a> MacroRender<'a> {
         if self.needs_bang() && self.ctx.snippet_cap().is_some() {
             format!("{}!{}…{}", self.name, self.bra, self.ket)
         } else {
-            self.banged_name()
+            if self.macro_.kind() == hir::MacroKind::Derive {
+                self.name.to_string()
+            } else {
+                self.banged_name()
+            }
         }
     }
 
diff --git a/crates/rust-analyzer/src/caps.rs b/crates/rust-analyzer/src/caps.rs
index 6b9753521..fe5255240 100644
--- a/crates/rust-analyzer/src/caps.rs
+++ b/crates/rust-analyzer/src/caps.rs
@@ -1,6 +1,4 @@
 //! Advertises the capabilities of the LSP Server.
-use std::env;
-
 use lsp_types::{
     CallHierarchyServerCapability, ClientCapabilities, CodeActionKind, CodeActionOptions,
     CodeActionProviderCapability, CodeLensOptions, CompletionOptions,
@@ -22,11 +20,7 @@ pub fn server_capabilities(config: &Config) -> ServerCapabilities {
     ServerCapabilities {
         text_document_sync: Some(TextDocumentSyncCapability::Options(TextDocumentSyncOptions {
             open_close: Some(true),
-            change: Some(if env::var("RA_NO_INCREMENTAL_SYNC").is_ok() {
-                TextDocumentSyncKind::Full
-            } else {
-                TextDocumentSyncKind::Incremental
-            }),
+            change: Some(TextDocumentSyncKind::Incremental),
             will_save: None,
             will_save_wait_until: None,
             save: Some(SaveOptions::default().into()),
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index 6d18d0ffc..f5c8535a2 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -534,6 +534,7 @@ pub(crate) fn folding_range(
         | FoldKind::Consts
         | FoldKind::Statics
         | FoldKind::WhereClause
+        | FoldKind::ReturnType
         | FoldKind::Array => None,
     };