Issue 40482. Fix for Function?.call() reporting unchecked nullable.

Bug: #40482
Change-Id: Ifb65cd8016dca18c634cd216759278b7518d41ef
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/135185
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analyzer/lib/src/dart/resolver/method_invocation_resolver.dart

@@ -423,7 +423,10 @@ class MethodInvocationResolver {
       InterfaceType receiverType, SimpleIdentifier nameNode, String name) {
     if (_isCoreFunction(receiverType) &&
         name == FunctionElement.CALL_METHOD_NAME) {
-      _resolver.nullableDereferenceVerifier.expression(receiver);
+      _resolver.nullableDereferenceVerifier.expression(
+        receiver,
+        type: receiverType,
+      );
       _setDynamicResolution(node);
       return;
     }

pkg/analyzer/lib/src/error/nullable_dereference_verifier.dart

@@ -21,12 +21,13 @@ class NullableDereferenceVerifier {
   })  : _typeSystem = typeSystem,
         _errorReporter = errorReporter;
 
-  bool expression(Expression expression) {
+  bool expression(Expression expression, {DartType type}) {
     if (!_typeSystem.isNonNullableByDefault) {
       return false;
     }
 
-    return _check(expression, expression.staticType);
+    type ??= expression.staticType;
+    return _check(expression, type);
   }
 
   void report(AstNode errorNode, DartType receiverType) {

pkg/analyzer/test/src/dart/resolution/method_invocation_test.dart

@@ -1725,6 +1725,40 @@ main() {
     );
   }
 
+  test_hasReceiver_interfaceQ_Function_call_checked() async {
+    await assertNoErrorsInCode(r'''
+void main(Function? foo) {
+  foo?.call();
+}
+''');
+
+    assertMethodInvocation2(
+      findNode.methodInvocation('foo?.call()'),
+      element: null,
+      typeArgumentTypes: [],
+      invokeType: 'dynamic',
+      type: 'dynamic',
+    );
+  }
+
+  test_hasReceiver_interfaceQ_Function_call_unchecked() async {
+    await assertErrorsInCode(r'''
+void main(Function? foo) {
+  foo.call();
+}
+''', [
+      error(StaticWarningCode.UNCHECKED_USE_OF_NULLABLE_VALUE, 29, 3),
+    ]);
+
+    assertMethodInvocation2(
+      findNode.methodInvocation('foo.call()'),
+      element: null,
+      typeArgumentTypes: [],
+      invokeType: 'dynamic',
+      type: 'dynamic',
+    );
+  }
+
   test_hasReceiver_interfaceTypeQ_defined() async {
     await assertErrorsInCode(r'''
 class A {

pkg/dev_compiler/tool/dartdevc_nnbd_sdk_error_golden.txt

@@ -1,2 +1 @@
-ERROR|STATIC_WARNING|UNCHECKED_USE_OF_NULLABLE_VALUE|lib/_http/http.dart|7638|7|11|The expression is nullable and must be null-checked before it can be used.
-ERROR|STATIC_WARNING|UNCHECKED_USE_OF_NULLABLE_VALUE|lib/_http/http.dart|8726|5|24|The expression is nullable and must be null-checked before it can be used.
+