Merge #4900

4900: Self variant enum res fix r=BGluth a=BGluth

Fixes #4789.

This is my first PR for this project, so it's probably worth giving it an extra close look.

A few things that I wasn't sure about:
- Is `resolve_path` really the best place to perform this check? It seemed like a natural place, but perhaps there's a better place?
- When handling the new variant `PathResolution::VariantDef`, I couldn't see an obvious variant of `TypeNs` to return in `in_type_ns` for Unions and Structs.

Co-authored-by: BGluth <gluthb@gmail.com>

crates/ra_hir/src/source_analyzer.rs

@@ -216,13 +216,43 @@ pub(crate) fn resolve_path(
             if let Some(assoc) = self.infer.as_ref()?.assoc_resolutions_for_expr(expr_id) {
                 return Some(PathResolution::AssocItem(assoc.into()));
             }
+            if let Some(VariantId::EnumVariantId(variant)) =
+                self.infer.as_ref()?.variant_resolution_for_expr(expr_id)
+            {
+                return Some(PathResolution::Def(ModuleDef::EnumVariant(variant.into())));
             }
+        }
+
         if let Some(path_pat) = path.syntax().parent().and_then(ast::PathPat::cast) {
             let pat_id = self.pat_id(&path_pat.into())?;
             if let Some(assoc) = self.infer.as_ref()?.assoc_resolutions_for_pat(pat_id) {
                 return Some(PathResolution::AssocItem(assoc.into()));
             }
+            if let Some(VariantId::EnumVariantId(variant)) =
+                self.infer.as_ref()?.variant_resolution_for_pat(pat_id)
+            {
+                return Some(PathResolution::Def(ModuleDef::EnumVariant(variant.into())));
             }
+        }
+
+        if let Some(rec_lit) = path.syntax().parent().and_then(ast::RecordLit::cast) {
+            let expr_id = self.expr_id(db, &rec_lit.into())?;
+            if let Some(VariantId::EnumVariantId(variant)) =
+                self.infer.as_ref()?.variant_resolution_for_expr(expr_id)
+            {
+                return Some(PathResolution::Def(ModuleDef::EnumVariant(variant.into())));
+            }
+        }
+
+        if let Some(rec_pat) = path.syntax().parent().and_then(ast::RecordPat::cast) {
+            let pat_id = self.pat_id(&rec_pat.into())?;
+            if let Some(VariantId::EnumVariantId(variant)) =
+                self.infer.as_ref()?.variant_resolution_for_pat(pat_id)
+            {
+                return Some(PathResolution::Def(ModuleDef::EnumVariant(variant.into())));
+            }
+        }
+
         // This must be a normal source file rather than macro file.
         let hir_path =
             crate::Path::from_src(path.clone(), &Hygiene::new(db.upcast(), self.file_id))?;

crates/ra_ide/src/goto_definition.rs

@@ -908,4 +908,84 @@ fn baz(foo: Foo) {
             "x: i32|x",
         );
     }
+
+    #[test]
+    fn goto_def_for_enum_variant_self_pattern_const() {
+        check_goto(
+            "
+            //- /lib.rs
+            enum Foo {
+                Bar,
+            }
+            impl Foo {
+                fn baz(self) {
+                    match self {
+                        Self::Bar<|> => {}
+                    }
+                }
+            }
+            ",
+            "Bar ENUM_VARIANT FileId(1) 15..18 15..18",
+            "Bar|Bar",
+        );
+    }
+
+    #[test]
+    fn goto_def_for_enum_variant_self_pattern_record() {
+        check_goto(
+            "
+            //- /lib.rs
+            enum Foo {
+                Bar { val: i32 },
+            }
+            impl Foo {
+                fn baz(self) -> i32 {
+                    match self {
+                        Self::Bar<|> { val } => {}
+                    }
+                }
+            }
+            ",
+            "Bar ENUM_VARIANT FileId(1) 15..31 15..18",
+            "Bar { val: i32 }|Bar",
+        );
+    }
+
+    #[test]
+    fn goto_def_for_enum_variant_self_expr_const() {
+        check_goto(
+            "
+            //- /lib.rs
+            enum Foo {
+                Bar,
+            }
+            impl Foo {
+                fn baz(self) {
+                    Self::Bar<|>;
+                }
+            }
+            ",
+            "Bar ENUM_VARIANT FileId(1) 15..18 15..18",
+            "Bar|Bar",
+        );
+    }
+
+    #[test]
+    fn goto_def_for_enum_variant_self_expr_record() {
+        check_goto(
+            "
+            //- /lib.rs
+            enum Foo {
+                Bar { val: i32 },
+            }
+            impl Foo {
+                fn baz(self) {
+                    Self::Bar<|> {val: 4};
+                }
+            }
+            ",
+            "Bar ENUM_VARIANT FileId(1) 15..31 15..18",
+            "Bar { val: i32 }|Bar",
+        );
+    }
 }