From 36a9daac70fe99d837ff3f5b2fb89d226423c1ba Mon Sep 17 00:00:00 2001
From: Daiki Ihara <sasurau4@gmail.com>
Date: Tue, 15 Dec 2020 00:39:42 +0900
Subject: [PATCH] Add find usages for enum constructors

---
 crates/ide/src/references.rs | 115 +++++++++++++++++++++++++++++++++++
 crates/ide_db/src/search.rs  |  15 +++++
 2 files changed, 130 insertions(+)

diff --git a/crates/ide/src/references.rs b/crates/ide/src/references.rs
index 7395b81bd29..66f0f7950f4 100644
--- a/crates/ide/src/references.rs
+++ b/crates/ide/src/references.rs
@@ -97,6 +97,9 @@ pub(crate) fn find_all_refs(
         get_struct_def_name_for_struct_literal_search(&sema, &syntax, position)
     {
         (Some(name), ReferenceKind::StructLiteral)
+    } else if let Some(name) = get_enum_def_name_for_struct_literal_search(&sema, &syntax, position)
+    {
+        (Some(name), ReferenceKind::EnumLiteral)
     } else {
         (
             sema.find_node_at_offset_with_descend::<ast::Name>(&syntax, position.offset),
@@ -198,6 +201,33 @@ fn get_struct_def_name_for_struct_literal_search(
     None
 }
 
+fn get_enum_def_name_for_struct_literal_search(
+    sema: &Semantics<RootDatabase>,
+    syntax: &SyntaxNode,
+    position: FilePosition,
+) -> Option<ast::Name> {
+    if let TokenAtOffset::Between(ref left, ref right) = syntax.token_at_offset(position.offset) {
+        if right.kind() != SyntaxKind::L_CURLY && right.kind() != SyntaxKind::L_PAREN {
+            return None;
+        }
+        if let Some(name) =
+            sema.find_node_at_offset_with_descend::<ast::Name>(&syntax, left.text_range().start())
+        {
+            return name.syntax().ancestors().find_map(ast::Enum::cast).and_then(|l| l.name());
+        }
+        if sema
+            .find_node_at_offset_with_descend::<ast::GenericParamList>(
+                &syntax,
+                left.text_range().start(),
+            )
+            .is_some()
+        {
+            return left.ancestors().find_map(ast::Enum::cast).and_then(|l| l.name());
+        }
+    }
+    None
+}
+
 fn try_find_self_references(
     syntax: &SyntaxNode,
     position: FilePosition,
@@ -356,6 +386,91 @@ fn main() {
         );
     }
 
+    #[test]
+    fn test_enum_after_space() {
+        check(
+            r#"
+enum Foo <|>{
+    A,
+    B,
+}
+fn main() {
+    let f: Foo;
+    f = Foo::A;
+}
+"#,
+            expect![[r#"
+                Foo ENUM FileId(0) 0..26 5..8 Other
+
+                FileId(0) 63..66 EnumLiteral
+            "#]],
+        );
+    }
+
+    #[test]
+    fn test_enum_before_space() {
+        check(
+            r#"
+enum Foo<|> {
+    A,
+    B,
+}
+fn main() {
+    let f: Foo;
+    f = Foo::A;
+}
+"#,
+            expect![[r#"
+                Foo ENUM FileId(0) 0..26 5..8 Other
+
+                FileId(0) 50..53 Other
+                FileId(0) 63..66 EnumLiteral
+            "#]],
+        );
+    }
+
+    #[test]
+    fn test_enum_with_generic_type() {
+        check(
+            r#"
+enum Foo<T> <|>{
+    A(T),
+    B,
+}
+fn main() {
+    let f: Foo<i8>;
+    f = Foo::A(1);
+}
+"#,
+            expect![[r#"
+                Foo ENUM FileId(0) 0..32 5..8 Other
+
+                FileId(0) 73..76 EnumLiteral
+            "#]],
+        );
+    }
+
+    #[test]
+    fn test_enum_for_tuple() {
+        check(
+            r#"
+enum Foo<|>{
+    A(i8),
+    B(i8),
+}
+fn main() {
+    let f: Foo;
+    f = Foo::A(1);
+}
+"#,
+            expect![[r#"
+                Foo ENUM FileId(0) 0..33 5..8 Other
+
+                FileId(0) 70..73 EnumLiteral
+            "#]],
+        );
+    }
+
     #[test]
     fn test_find_all_refs_for_local() {
         check(
diff --git a/crates/ide_db/src/search.rs b/crates/ide_db/src/search.rs
index 607185ca97f..3936c7390fc 100644
--- a/crates/ide_db/src/search.rs
+++ b/crates/ide_db/src/search.rs
@@ -32,6 +32,7 @@ pub enum ReferenceKind {
     StructLiteral,
     RecordFieldExprOrPat,
     SelfKw,
+    EnumLiteral,
     Other,
 }
 
@@ -284,6 +285,8 @@ fn found_name_ref(
                     ReferenceKind::RecordFieldExprOrPat
                 } else if is_record_lit_name_ref(&name_ref) || is_call_expr_name_ref(&name_ref) {
                     ReferenceKind::StructLiteral
+                } else if is_enum_lit_name_ref(&name_ref) {
+                    ReferenceKind::EnumLiteral
                 } else {
                     ReferenceKind::Other
                 };
@@ -402,3 +405,15 @@ fn is_record_field_expr_or_pat(name_ref: &ast::NameRef) -> bool {
         false
     }
 }
+
+fn is_enum_lit_name_ref(name_ref: &ast::NameRef) -> bool {
+    name_ref
+        .syntax()
+        .ancestors()
+        .find_map(ast::PathExpr::cast)
+        .and_then(|p| p.path())
+        .and_then(|p| p.qualifier())
+        .and_then(|p| p.segment())
+        .map(|p| p.name_ref().as_ref() == Some(name_ref))
+        .unwrap_or(false)
+}