fix: don't complete derive macros as fn-like macros

Author: jonas-schievink

crates/hir/src/lib.rs

@@ -1351,6 +1351,13 @@ impl MacroDef {
             MacroDefKind::ProcMacro(_, base_db::ProcMacroKind::FuncLike, _) => MacroKind::ProcMacro,
         }
     }
+
+    pub fn is_fn_like(&self) -> bool {
+        match self.kind() {
+            MacroKind::Declarative | MacroKind::BuiltIn | MacroKind::ProcMacro => true,
+            MacroKind::Attr | MacroKind::Derive => false,
+        }
+    }
 }
 
 /// Invariant: `inner.as_assoc_item(db).is_some()`

crates/ide_completion/src/completions/pattern.rs

@@ -39,7 +39,7 @@ pub(crate) fn complete_pattern(acc: &mut Completions, ctx: &CompletionContext) {
                 | hir::ModuleDef::Module(..) => refutable,
                 _ => false,
             },
-            hir::ScopeDef::MacroDef(_) => true,
+            hir::ScopeDef::MacroDef(mac) => mac.is_fn_like(),
             hir::ScopeDef::ImplSelfType(impl_) => match impl_.self_ty(ctx.db).as_adt() {
                 Some(hir::Adt::Struct(strukt)) => {
                     acc.add_struct_pat(ctx, strukt, Some(name.clone()));
@@ -101,6 +101,28 @@ fn foo() {
         );
     }
 
+    #[test]
+    fn does_not_complete_non_fn_macros() {
+        check(
+            r#"
+macro_rules! m { ($e:expr) => { $e } }
+enum E { X }
+
+#[rustc_builtin_macro]
+macro Clone {}
+
+fn foo() {
+   match E::X { $0 }
+}
+"#,
+            expect![[r#"
+                ev E::X  ()
+                en E
+                ma m!(…) macro_rules! m
+            "#]],
+        );
+    }
+
     #[test]
     fn completes_in_simple_macro_call() {
         check(

crates/ide_completion/src/completions/qualified_path.rs

@@ -26,7 +26,9 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
             let module_scope = module.scope(ctx.db, context_module);
             for (name, def) in module_scope {
                 if let hir::ScopeDef::MacroDef(macro_def) = def {
-                    acc.add_macro(ctx, Some(name.clone()), macro_def);
+                    if macro_def.is_fn_like() {
+                        acc.add_macro(ctx, Some(name.clone()), macro_def);
+                    }
                 }
                 if let hir::ScopeDef::ModuleDef(hir::ModuleDef::Module(_)) = def {
                     acc.add_resolution(ctx, name, &def);
@@ -58,6 +60,13 @@ pub(crate) fn complete_qualified_path(acc: &mut Completions, ctx: &CompletionCon
                     }
                 }
 
+                if let hir::ScopeDef::MacroDef(macro_def) = def {
+                    if !macro_def.is_fn_like() {
+                        // Don't suggest attribute macros and derives.
+                        continue;
+                    }
+                }
+
                 acc.add_resolution(ctx, name, &def);
             }
         }

crates/ide_completion/src/completions/unqualified_path.rs

@@ -13,7 +13,9 @@ pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
         // only show macros in {Assoc}ItemList
         ctx.scope.process_all_names(&mut |name, res| {
             if let hir::ScopeDef::MacroDef(mac) = res {
-                acc.add_macro(ctx, Some(name.clone()), mac);
+                if mac.is_fn_like() {
+                    acc.add_macro(ctx, Some(name.clone()), mac);
+                }
             }
             if let hir::ScopeDef::ModuleDef(hir::ModuleDef::Module(_)) = res {
                 acc.add_resolution(ctx, name, &res);
@@ -46,7 +48,13 @@ pub(crate) fn complete_unqualified_path(acc: &mut Completions, ctx: &CompletionC
             cov_mark::hit!(skip_lifetime_completion);
             return;
         }
-        acc.add_resolution(ctx, name, &res);
+        let add_resolution = match res {
+            ScopeDef::MacroDef(mac) => mac.is_fn_like(),
+            _ => true,
+        };
+        if add_resolution {
+            acc.add_resolution(ctx, name, &res);
+        }
     });
 }
 
@@ -426,6 +434,44 @@ mod macros {
         );
     }
 
+    #[test]
+    fn does_not_complete_non_fn_macros() {
+        check(
+            r#"
+#[rustc_builtin_macro]
+pub macro Clone {}
+
+fn f() {$0}
+"#,
+            expect![[r#"
+                fn f() fn()
+            "#]],
+        );
+        check(
+            r#"
+#[rustc_builtin_macro]
+pub macro Clone {}
+
+struct S;
+impl S {
+    $0
+}
+"#,
+            expect![[r#""#]],
+        );
+        check(
+            r#"
+mod m {
+    #[rustc_builtin_macro]
+    pub macro Clone {}
+}
+
+fn f() {m::$0}
+"#,
+            expect![[r#""#]],
+        );
+    }
+
     #[test]
     fn completes_std_prelude_if_core_is_defined() {
         check(