[analyzer] Update Name.forSetter to only add trailing = if not already there

Change-Id: Id6d98a9a2902539635d2cb5acd23d3ddd4832d5d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/391442
Reviewed-by: Samuel Rawlins <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Brian Wilkerson <[email protected]>

Author: DanTup

pkg/analyzer/lib/src/dart/element/inheritance_manager3.dart

@@ -1314,7 +1314,11 @@ class Name {
   }
 
   Name get forSetter {
-    return Name(libraryUri, '$name=');
+    if (name.endsWith('=')) {
+      return this;
+    } else {
+      return Name(libraryUri, '$name=');
+    }
   }
 
   @override

pkg/analyzer/test/src/dart/element/inheritance_manager3_test.dart

@@ -25,6 +25,7 @@ main() {
     defineReflectiveTests(InheritanceManager3Test);
     defineReflectiveTests(InheritanceManager3Test_elements);
     defineReflectiveTests(InheritanceManager3Test_ExtensionType);
+    defineReflectiveTests(InheritanceManager3NameTest);
     defineReflectiveTests(UpdateNodeTextExpectations);
   });
 }
@@ -1413,6 +1414,47 @@ class B extends A {
   }
 }
 
+@reflectiveTest
+class InheritanceManager3NameTest {
+  test_equals() {
+    expect(Name(null, 'foo'), Name(null, 'foo'));
+    expect(Name(null, 'foo'), Name(null, 'foo=').forGetter);
+    expect(Name(null, 'foo='), Name(null, 'foo='));
+    expect(Name(null, 'foo='), Name(null, 'foo').forSetter);
+    expect(Name(null, 'foo='), Name(null, 'foo').forSetter.forSetter.forSetter);
+  }
+
+  test_forGetter() {
+    var name = Name(null, 'foo');
+    expect(name.forGetter.name, 'foo');
+    expect(name, name.forGetter);
+  }
+
+  test_forGetter_fromSetter() {
+    var name = Name(null, 'foo=');
+    expect(name.forGetter.name, 'foo');
+  }
+
+  test_forSetter() {
+    var name = Name(null, 'foo=');
+    expect(name.forSetter.name, 'foo=');
+    expect(name, name.forSetter);
+  }
+
+  test_forSetter_fromGetter() {
+    var name = Name(null, 'foo');
+    expect(name.forSetter.name, 'foo=');
+  }
+
+  test_name_getter() {
+    expect(Name(null, 'foo').name, 'foo');
+  }
+
+  test_name_setter() {
+    expect(Name(null, 'foo=').name, 'foo=');
+  }
+}
+
 @reflectiveTest
 class InheritanceManager3Test extends _InheritanceManager3Base {
   test_getInherited_closestSuper() async {