[analyzer] Handle Function.call methods in ElementLocator

Fixes the hover part of #61319

Change-Id: Iabff1bf61c14ade37d9392f65709a5d6e0750643
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/448980
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

Author: DanTup

pkg/analysis_server/test/lsp/hover_test.dart

@@ -628,6 +628,26 @@ print();
     String [!a^bc!] = '';
     ''', contains('This is a string.'));
 
+  Future<void> test_method_callMethod() async {
+    var content = '''
+/// f doc.
+void f(int i) {
+  f.[!call^!](1);
+}
+''';
+    var expected = '''
+```dart
+void f(int i)
+```
+Type: `void Function(int)`
+
+Declared in _package:test/main.dart_.
+
+---
+f doc.''';
+    await assertStringContents(content, equals(expected));
+  }
+
   Future<void> test_method_mixin_onImplementation() async {
     var content = '''
 abstract class A {

pkg/analyzer/lib/src/dart/ast/element_locator.dart

@@ -5,6 +5,7 @@
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/ast/extensions.dart';
 
 /// An object used to locate the [Element] associated with a given [AstNode].
@@ -192,6 +193,14 @@ class _ElementMapper2 extends GeneralizingAstVisitor<Element> {
         return grandParent.element;
       }
       return null;
+    } else if (parent is MethodInvocation &&
+        parent.methodName == node &&
+        parent.methodName.name == MethodElement.CALL_METHOD_NAME) {
+      // Handle .call() invocations on functions.
+      var method = parent.realTarget;
+      if (method is Identifier && method.staticType is FunctionType) {
+        return method.element;
+      }
     }
     return node.writeOrReadElement;
   }

pkg/analyzer/test/src/dart/ast/element_locator_test.dart

@@ -453,6 +453,51 @@ class A {
 ''');
   }
 
+  test_locate_MethodInvocation_class_callMethod_argument() async {
+    await resolveTestCode(r'''
+class A {
+  void call(int i) {}
+}
+void f(A a) {
+  a.call(1);
+}
+''');
+    var node = findNode.methodInvocation('call(1)').methodName;
+    var element = ElementLocator.locate(node);
+    _assertElement(element, r'''
+<testLibrary>::@class::A::@method::call
+''');
+  }
+
+  test_locate_MethodInvocation_class_callMethod_constructor() async {
+    await resolveTestCode(r'''
+class A {
+  void call(int i) {}
+}
+void f() {
+  A().call(1);
+}
+''');
+    var node = findNode.methodInvocation('call(1)').methodName;
+    var element = ElementLocator.locate(node);
+    _assertElement(element, r'''
+<testLibrary>::@class::A::@method::call
+''');
+  }
+
+  test_locate_MethodInvocation_function_callMethod() async {
+    await resolveTestCode(r'''
+void f(int i) {
+  f.call(1);
+}
+''');
+    var node = findNode.methodInvocation('call').methodName;
+    var element = ElementLocator.locate(node);
+    _assertElement(element, r'''
+<testLibrary>::@function::f
+''');
+  }
+
   test_locate_MethodInvocation_method() async {
     await resolveTestCode(r'''
 class A {