11 files changed, 98 insertions, 66 deletions

diff --git a/crates/ide_completion/src/completions/attribute.rs b/crates/ide_completion/src/completions/attribute.rs
index f80d7eec3..d3392100d 100644
--- a/crates/ide_completion/src/completions/attribute.rs
+++ b/crates/ide_completion/src/completions/attribute.rs
@@ -3,6 +3,7 @@
 //! This module uses a bit of static metadata to provide completions
 //! for built-in attributes.
 
+use hir::HasAttrs;
 use ide_db::helpers::generated_lints::{CLIPPY_LINTS, DEFAULT_LINTS, FEATURES};
 use once_cell::sync::Lazy;
 use rustc_hash::{FxHashMap, FxHashSet};
@@ -81,6 +82,24 @@ fn complete_new_attribute(acc: &mut Completions, ctx: &CompletionContext, attrib
         None if is_inner => ATTRIBUTES.iter().for_each(add_completion),
         None => ATTRIBUTES.iter().filter(|compl| !compl.prefer_inner).for_each(add_completion),
     }
+
+    // FIXME: write a test for this when we can
+    ctx.scope.process_all_names(&mut |name, scope_def| {
+        if let hir::ScopeDef::MacroDef(mac) = scope_def {
+            if mac.kind() == hir::MacroKind::Attr {
+                let mut item = CompletionItem::new(
+                    CompletionKind::Attribute,
+                    ctx.source_range(),
+                    name.to_string(),
+                );
+                item.kind(CompletionItemKind::Attribute);
+                if let Some(docs) = mac.docs(ctx.sema.db) {
+                    item.documentation(docs);
+                }
+                acc.add(item.build());
+            }
+        }
+    });
 }
 
 struct AttrCompletion {
diff --git a/crates/ide_completion/src/completions/attribute/derive.rs b/crates/ide_completion/src/completions/attribute/derive.rs
index 0bc3eab98..d526824fb 100644
--- a/crates/ide_completion/src/completions/attribute/derive.rs
+++ b/crates/ide_completion/src/completions/attribute/derive.rs
@@ -1,6 +1,7 @@
 //! Completion for derives
+use hir::HasAttrs;
 use itertools::Itertools;
-use rustc_hash::FxHashSet;
+use rustc_hash::FxHashMap;
 use syntax::ast;
 
 use crate::{
@@ -15,66 +16,64 @@ pub(super) fn complete_derive(
     derive_input: ast::TokenTree,
 ) {
     if let Some(existing_derives) = super::parse_comma_sep_input(derive_input) {
-        for derive_completion in DEFAULT_DERIVE_COMPLETIONS
-            .iter()
-            .filter(|completion| !existing_derives.contains(completion.label))
-        {
-            let mut components = vec![derive_completion.label];
-            components.extend(
-                derive_completion
-                    .dependencies
-                    .iter()
-                    .filter(|&&dependency| !existing_derives.contains(dependency)),
-            );
-            let lookup = components.join(", ");
-            let label = components.iter().rev().join(", ");
+        for (derive, docs) in get_derive_names_in_scope(ctx) {
+            let (label, lookup) = if let Some(derive_completion) = DEFAULT_DERIVE_COMPLETIONS
+                .iter()
+                .find(|derive_completion| derive_completion.label == derive)
+            {
+                let mut components = vec![derive_completion.label];
+                components.extend(
+                    derive_completion
+                        .dependencies
+                        .iter()
+                        .filter(|&&dependency| !existing_derives.contains(dependency)),
+                );
+                let lookup = components.join(", ");
+                let label = components.iter().rev().join(", ");
+                (label, Some(lookup))
+            } else {
+                (derive, None)
+            };
             let mut item =
                 CompletionItem::new(CompletionKind::Attribute, ctx.source_range(), label);
-            item.lookup_by(lookup).kind(CompletionItemKind::Attribute);
-            item.add_to(acc);
-        }
-
-        for custom_derive_name in get_derive_names_in_scope(ctx).difference(&existing_derives) {
-            let mut item = CompletionItem::new(
-                CompletionKind::Attribute,
-                ctx.source_range(),
-                custom_derive_name,
-            );
             item.kind(CompletionItemKind::Attribute);
+            if let Some(docs) = docs {
+                item.documentation(docs);
+            }
+            if let Some(lookup) = lookup {
+                item.lookup_by(lookup);
+            }
             item.add_to(acc);
         }
     }
 }
 
-fn get_derive_names_in_scope(ctx: &CompletionContext) -> FxHashSet<String> {
-    let mut result = FxHashSet::default();
+fn get_derive_names_in_scope(
+    ctx: &CompletionContext,
+) -> FxHashMap<String, Option<hir::Documentation>> {
+    let mut result = FxHashMap::default();
     ctx.scope.process_all_names(&mut |name, scope_def| {
         if let hir::ScopeDef::MacroDef(mac) = scope_def {
             if mac.kind() == hir::MacroKind::Derive {
-                result.insert(name.to_string());
+                result.insert(name.to_string(), mac.docs(ctx.db));
             }
         }
     });
     result
 }
 
-struct DeriveCompletion {
+struct DeriveDependencies {
     label: &'static str,
     dependencies: &'static [&'static str],
 }
 
-/// Standard Rust derives and the information about their dependencies
+/// Standard Rust derives that have dependencies
 /// (the dependencies are needed so that the main derive don't break the compilation when added)
-const DEFAULT_DERIVE_COMPLETIONS: &[DeriveCompletion] = &[
-    DeriveCompletion { label: "Clone", dependencies: &[] },
-    DeriveCompletion { label: "Copy", dependencies: &["Clone"] },
-    DeriveCompletion { label: "Debug", dependencies: &[] },
-    DeriveCompletion { label: "Default", dependencies: &[] },
-    DeriveCompletion { label: "Hash", dependencies: &[] },
-    DeriveCompletion { label: "PartialEq", dependencies: &[] },
-    DeriveCompletion { label: "Eq", dependencies: &["PartialEq"] },
-    DeriveCompletion { label: "PartialOrd", dependencies: &["PartialEq"] },
-    DeriveCompletion { label: "Ord", dependencies: &["PartialOrd", "Eq", "PartialEq"] },
+const DEFAULT_DERIVE_COMPLETIONS: &[DeriveDependencies] = &[
+    DeriveDependencies { label: "Copy", dependencies: &["Clone"] },
+    DeriveDependencies { label: "Eq", dependencies: &["PartialEq"] },
+    DeriveDependencies { label: "Ord", dependencies: &["PartialOrd", "Eq", "PartialEq"] },
+    DeriveDependencies { label: "PartialOrd", dependencies: &["PartialEq"] },
 ];
 
 #[cfg(test)]
@@ -94,6 +93,7 @@ mod tests {
     }
 
     #[test]
+    #[ignore] // FIXME: Fixtures cant test proc-macros/derives yet as we cant specify them in fixtures
     fn empty_derive() {
         check(
             r#"#[derive($0)] struct Test;"#,
@@ -112,6 +112,7 @@ mod tests {
     }
 
     #[test]
+    #[ignore] // FIXME: Fixtures cant test proc-macros/derives yet as we cant specify them in fixtures
     fn derive_with_input() {
         check(
             r#"#[derive(serde::Serialize, PartialEq, $0)] struct Test;"#,
@@ -129,6 +130,7 @@ mod tests {
     }
 
     #[test]
+    #[ignore] // FIXME: Fixtures cant test proc-macros/derives yet as we cant specify them in fixtures
     fn derive_with_input2() {
         check(
             r#"#[derive($0 serde::Serialize, PartialEq)] struct Test;"#,
diff --git a/crates/ide_completion/src/completions/attribute/lint.rs b/crates/ide_completion/src/completions/attribute/lint.rs
index b486c9093..ca99e9759 100644
--- a/crates/ide_completion/src/completions/attribute/lint.rs
+++ b/crates/ide_completion/src/completions/attribute/lint.rs
@@ -24,7 +24,8 @@ pub(super) fn complete_lint(
                 ctx.source_range(),
                 lint_completion.label,
             );
-            item.kind(CompletionItemKind::Attribute).detail(lint_completion.description);
+            item.kind(CompletionItemKind::Attribute)
+                .documentation(hir::Documentation::new(lint_completion.description.to_owned()));
             item.add_to(acc)
         }
     }
@@ -61,4 +62,13 @@ mod tests {
             r#"#[allow(keyword_idents, deprecated)] struct Test;"#,
         )
     }
+
+    #[test]
+    fn check_feature() {
+        check_edit(
+            "box_syntax",
+            r#"#[feature(box_$0)] struct Test;"#,
+            r#"#[feature(box_syntax)] struct Test;"#,
+        )
+    }
 }
diff --git a/crates/ide_completion/src/completions/dot.rs b/crates/ide_completion/src/completions/dot.rs
index e0a7021fd..8ad57a069 100644
--- a/crates/ide_completion/src/completions/dot.rs
+++ b/crates/ide_completion/src/completions/dot.rs
@@ -4,7 +4,7 @@ use either::Either;
 use hir::{HasVisibility, ScopeDef};
 use rustc_hash::FxHashSet;
 
-use crate::{context::CompletionContext, Completions};
+use crate::{context::CompletionContext, patterns::ImmediateLocation, Completions};
 
 /// Complete dot accesses, i.e. fields or methods.
 pub(crate) fn complete_dot(acc: &mut Completions, ctx: &CompletionContext) {
@@ -18,7 +18,7 @@ pub(crate) fn complete_dot(acc: &mut Completions, ctx: &CompletionContext) {
         _ => return,
     };
 
-    if ctx.is_call {
+    if matches!(ctx.completion_location, Some(ImmediateLocation::MethodCall { .. })) {
         cov_mark::hit!(test_no_struct_field_completion_for_method_call);
     } else {
         complete_fields(ctx, &receiver_ty, |field, ty| match field {
@@ -33,7 +33,7 @@ fn complete_undotted_self(acc: &mut Completions, ctx: &CompletionContext) {
     if !ctx.config.enable_self_on_the_fly {
         return;
     }
-    if !ctx.is_trivial_path || ctx.is_path_disallowed() {
+    if !ctx.is_trivial_path() || ctx.is_path_disallowed() {
         return;
     }
     ctx.scope.process_all_names(&mut |name, def| {
diff --git a/crates/ide_completion/src/completions/flyimport.rs b/crates/ide_completion/src/completions/flyimport.rs
index d72bf13d3..7bf47bf75 100644
--- a/crates/ide_completion/src/completions/flyimport.rs
+++ b/crates/ide_completion/src/completions/flyimport.rs
@@ -161,13 +161,13 @@ pub(crate) fn position_for_import<'a>(
 ) -> Option<&'a SyntaxNode> {
     Some(match import_candidate {
         Some(ImportCandidate::Path(_)) => ctx.name_ref_syntax.as_ref()?.syntax(),
-        Some(ImportCandidate::TraitAssocItem(_)) => ctx.path_qual.as_ref()?.syntax(),
+        Some(ImportCandidate::TraitAssocItem(_)) => ctx.path_qual()?.syntax(),
         Some(ImportCandidate::TraitMethod(_)) => ctx.dot_receiver()?.syntax(),
         None => ctx
             .name_ref_syntax
             .as_ref()
             .map(|name_ref| name_ref.syntax())
-            .or_else(|| ctx.path_qual.as_ref().map(|path| path.syntax()))
+            .or_else(|| ctx.path_qual().map(|path| path.syntax()))
             .or_else(|| ctx.dot_receiver().map(|expr| expr.syntax()))?,
     })
 }
@@ -190,7 +190,7 @@ fn import_assets(ctx: &CompletionContext, fuzzy_name: String) -> Option<ImportAs
         };
         let assets_for_path = ImportAssets::for_fuzzy_path(
             current_module,
-            ctx.path_qual.clone(),
+            ctx.path_qual().cloned(),
             fuzzy_name,
             &ctx.sema,
             approximate_node,
diff --git a/crates/ide_completion/src/completions/keyword.rs b/crates/ide_completion/src/completions/keyword.rs
index 1a7a484a4..0ca97a0e4 100644
--- a/crates/ide_completion/src/completions/keyword.rs
+++ b/crates/ide_completion/src/completions/keyword.rs
@@ -19,11 +19,12 @@ pub(crate) fn complete_use_tree_keyword(acc: &mut Completions, ctx: &CompletionC
     };
 
     if ctx.use_item_syntax.is_some() {
-        if ctx.path_qual.is_none() {
+        let qual = ctx.path_qual();
+        if qual.is_none() {
             kw_completion("crate::").add_to(acc);
         }
         kw_completion("self").add_to(acc);
-        if iter::successors(ctx.path_qual.clone(), |p| p.qualifier())
+        if iter::successors(qual.cloned(), |p| p.qualifier())
             .all(|p| p.segment().and_then(|s| s.super_token()).is_some())
         {
             kw_completion("super::").add_to(acc);
@@ -128,7 +129,7 @@ pub(crate) fn complete_expr_keyword(acc: &mut Completions, ctx: &CompletionConte
     }
 
     if ctx.in_loop_body {
-        if ctx.can_be_stmt {
+        if ctx.can_be_stmt() {
             add_keyword("continue", "continue;");
             add_keyword("break", "break;");
         } else {
@@ -137,7 +138,7 @@ pub(crate) fn complete_expr_keyword(acc: &mut Completions, ctx: &CompletionConte
         }
     }
 
-    if !ctx.is_trivial_path {
+    if !ctx.is_trivial_path() {
         return;
     }
     let fn_def = match &ctx.function_def {
@@ -147,7 +148,7 @@ pub(crate) fn complete_expr_keyword(acc: &mut Completions, ctx: &CompletionConte
 
     add_keyword(
         "return",
-        match (ctx.can_be_stmt, fn_def.ret_type().is_some()) {
+        match (ctx.can_be_stmt(), fn_def.ret_type().is_some()) {
             (true, true) => "return $0;",
             (true, false) => "return;",
             (false, true) => "return $0",
diff --git a/crates/ide_completion/src/completions/postfix.rs b/crates/ide_completion/src/completions/postfix.rs
index 86bbb58e2..86eb21714 100644
--- a/crates/ide_completion/src/completions/postfix.rs
+++ b/crates/ide_completion/src/completions/postfix.rs
@@ -24,7 +24,7 @@ pub(crate) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
     }
 
     let (dot_receiver, receiver_is_ambiguous_float_literal) = match &ctx.completion_location {
-        Some(ImmediateLocation::MethodCall { receiver: Some(it) }) => (it, false),
+        Some(ImmediateLocation::MethodCall { receiver: Some(it), .. }) => (it, false),
         Some(ImmediateLocation::FieldAccess {
             receiver: Some(it),
             receiver_is_ambiguous_float_literal,
diff --git a/crates/ide_completion/src/completions/postfix/format_like.rs b/crates/ide_completion/src/completions/postfix/format_like.rs
index 0dcb3e898..9ebe1dcc0 100644
--- a/crates/ide_completion/src/completions/postfix/format_like.rs
+++ b/crates/ide_completion/src/completions/postfix/format_like.rs
@@ -4,15 +4,15 @@
 //
 // The following postfix snippets are available:
 //
-// - `format` -> `format!(...)`
-// - `panic` -> `panic!(...)`
-// - `println` -> `println!(...)`
-// - `log`:
-//   + `logd` -> `log::debug!(...)`
-//   + `logt` -> `log::trace!(...)`
-//   + `logi` -> `log::info!(...)`
-//   + `logw` -> `log::warn!(...)`
-//   + `loge` -> `log::error!(...)`
+// * `format` -> `format!(...)`
+// * `panic` -> `panic!(...)`
+// * `println` -> `println!(...)`
+// * `log`:
+// ** `logd` -> `log::debug!(...)`
+// ** `logt` -> `log::trace!(...)`
+// ** `logi` -> `log::info!(...)`
+// ** `logw` -> `log::warn!(...)`
+// ** `loge` -> `log::error!(...)`
 //
 // image::https://user-images.githubusercontent.com/48062697/113020656-b560f500-917a-11eb-87de-02991f61beb8.gif[]
 
diff --git a/crates/ide_completion/src/completions/qualified_path.rs b/crates/ide_completion/src/completions/qualified_path.rs
index de58ce1cd..c072de7b5 100644
--- a/crates/ide_completion/src/completions/qualified_path.rs
+++ b/crates/ide_completion/src/completions/qualified_path.rs
@@ -10,8 +10,8 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
     if ctx.is_path_disallowed() || ctx.expects_item() {
         return;
     }
-    let path = match &ctx.path_qual {
-        Some(path) => path.clone(),
+    let path = match ctx.path_qual() {
+        Some(path) => path,
         None => return,
     };
 
diff --git a/crates/ide_completion/src/completions/snippet.rs b/crates/ide_completion/src/completions/snippet.rs
index 6e6a6eb92..59a338e7b 100644
--- a/crates/ide_completion/src/completions/snippet.rs
+++ b/crates/ide_completion/src/completions/snippet.rs
@@ -14,7 +14,7 @@ fn snippet(ctx: &CompletionContext, cap: SnippetCap, label: &str, snippet: &str)
 }
 
 pub(crate) fn complete_expr_snippet(acc: &mut Completions, ctx: &CompletionContext) {
-    if !(ctx.is_trivial_path && ctx.function_def.is_some()) {
+    if !(ctx.is_trivial_path() && ctx.function_def.is_some()) {
         return;
     }
     let cap = match ctx.config.snippet_cap {
@@ -22,7 +22,7 @@ pub(crate) fn complete_expr_snippet(acc: &mut Completions, ctx: &CompletionConte
         None => return,
     };
 
-    if ctx.can_be_stmt {
+    if ctx.can_be_stmt() {
         snippet(ctx, cap, "pd", "eprintln!(\"$0 = {:?}\", $0);").add_to(acc);
         snippet(ctx, cap, "ppd", "eprintln!(\"$0 = {:#?}\", $0);").add_to(acc);
     }
diff --git a/crates/ide_completion/src/completions/unqualified_path.rs b/crates/ide_completion/src/completions/unqualified_path.rs
index bd955aa85..f321ed52b 100644
--- a/crates/ide_completion/src/completions/unqualified_path.rs
+++ b/crates/ide_completion/src/completions/unqualified_path.rs
@@ -5,7 +5,7 @@ use hir::ScopeDef;
 use crate::{CompletionContext, Completions};
 
 pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionContext) {
-    if !ctx.is_trivial_path {
+    if !ctx.is_trivial_path() {
         return;
     }
     if ctx.is_path_disallowed() || ctx.expects_item() {