Elements. Add types for recently fixed TOP_MERGE bugs.

See https://dart-review.googlesource.com/c/sdk/+/490120

Change-Id: I26451c651fb57d90f09ca5a62be02e859ac63a1f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/490240
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Paul Berry <paulberry@google.com>

Author: scheglov

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

@@ -32,30 +32,7 @@ class TopMergeTest extends AbstractTypeSystemTest {
     _check(dynamicType, dynamicType, dynamicType);
   }
 
-  test_function() {
-    _check(
-      functionTypeNone(returnType: voidNone),
-      functionTypeNone(returnType: objectQuestion),
-      functionTypeNone(returnType: objectQuestion),
-    );
-
-    _check(
-      functionTypeNone(
-        returnType: voidNone,
-        formalParameters: [requiredParameter(type: objectQuestion, name: 'a')],
-      ),
-      functionTypeNone(
-        returnType: voidNone,
-        formalParameters: [requiredParameter(type: dynamicType, name: 'a')],
-      ),
-      functionTypeNone(
-        returnType: voidNone,
-        formalParameters: [requiredParameter(type: objectQuestion, name: 'a')],
-      ),
-    );
-  }
-
-  test_function_covariant() {
+  test_function_parameters_covariant() {
     _check(
       functionTypeNone(
         returnType: voidNone,
@@ -91,22 +68,37 @@ class TopMergeTest extends AbstractTypeSystemTest {
     );
   }
 
-  test_function_parameters_mismatch() {
+  test_function_parameters_kind_optionalPositional_optionalPositional() {
     _check(
       functionTypeNone(
         returnType: voidNone,
-        formalParameters: [requiredParameter(type: intNone, name: 'a')],
+        formalParameters: [positionalParameter(type: intNone)],
       ),
       functionTypeNone(
         returnType: voidNone,
-        formalParameters: [requiredParameter(type: intNone, name: 'b')],
+        formalParameters: [positionalParameter(type: intNone)],
       ),
       functionTypeNone(
         returnType: voidNone,
-        formalParameters: [requiredParameter(type: intNone, name: 'a')],
+        formalParameters: [positionalParameter(type: intNone)],
+      ),
+    );
+  }
+
+  test_function_parameters_kind_requiredNamed_optionalNamed() {
+    _checkThrows(
+      functionTypeNone(
+        returnType: voidNone,
+        formalParameters: [namedRequiredParameter(type: intNone, name: 'a')],
+      ),
+      functionTypeNone(
+        returnType: voidNone,
+        formalParameters: [namedParameter(type: intNone, name: 'a')],
       ),
     );
+  }
 
+  test_function_parameters_kind_requiredPositional_optionalPositional() {
     _checkThrows(
       functionTypeNone(
         returnType: voidNone,
@@ -130,6 +122,48 @@ class TopMergeTest extends AbstractTypeSystemTest {
     );
   }
 
+  test_function_parameters_mismatch() {
+    _check(
+      functionTypeNone(
+        returnType: voidNone,
+        formalParameters: [requiredParameter(type: intNone, name: 'a')],
+      ),
+      functionTypeNone(
+        returnType: voidNone,
+        formalParameters: [requiredParameter(type: intNone, name: 'b')],
+      ),
+      functionTypeNone(
+        returnType: voidNone,
+        formalParameters: [requiredParameter(type: intNone, name: 'a')],
+      ),
+    );
+  }
+
+  test_function_parameters_type() {
+    _check(
+      functionTypeNone(
+        returnType: voidNone,
+        formalParameters: [requiredParameter(type: objectQuestion, name: 'a')],
+      ),
+      functionTypeNone(
+        returnType: voidNone,
+        formalParameters: [requiredParameter(type: dynamicType, name: 'a')],
+      ),
+      functionTypeNone(
+        returnType: voidNone,
+        formalParameters: [requiredParameter(type: objectQuestion, name: 'a')],
+      ),
+    );
+  }
+
+  test_function_returnType() {
+    _check(
+      functionTypeNone(returnType: voidNone),
+      functionTypeNone(returnType: objectQuestion),
+      functionTypeNone(returnType: objectQuestion),
+    );
+  }
+
   test_function_typeParameters_boundsMerge() {
     var T1 = typeParameter('T', bound: dynamicType);
     var T2 = typeParameter('T', bound: objectQuestion);