[VM generic functions] Disallow generic function types as type argume…

…nts or bounds.

Adjust existing test and status file.

R=asiva@google.com

Review-Url: https://codereview.chromium.org/2989513002 .

runtime/vm/class_finalizer.cc

@@ -796,6 +796,19 @@ intptr_t ClassFinalizer::ExpandAndFinalizeTypeArguments(
           if (type_arg.IsMalformed()) {
             // Malformed type arguments are mapped to dynamic.
             type_arg = Type::DynamicType();
+          } else if (type_arg.IsFunctionType()) {
+            const Function& signature_function =
+                Function::Handle(zone, Type::Cast(type_arg).signature());
+            if (signature_function.IsGeneric()) {
+              const String& type_arg_name =
+                  String::Handle(zone, type_arg.UserVisibleName());
+              const String& type_name =
+                  String::Handle(zone, type.UserVisibleName());
+              ReportError(cls, type_arg.token_pos(),
+                          "generic function type '%s' not allowed as type "
+                          "argument of type '%s'",
+                          type_arg_name.ToCString(), type_name.ToCString());
+            }
           }
           full_arguments.SetTypeAt(offset + i, type_arg);
         }
@@ -1341,6 +1354,18 @@ void ClassFinalizer::ResolveSignature(const Class& cls,
       type_param ^= type_params.TypeAt(i);
       type = type_param.bound();
       ResolveType(cls, type);
+      if (type.IsFunctionType()) {
+        const Function& signature_function =
+            Function::Handle(Type::Cast(type).signature());
+        if (signature_function.IsGeneric()) {
+          const String& type_name = String::Handle(type.UserVisibleName());
+          const String& type_param_name = String::Handle(type_param.name());
+          ReportError(cls, type.token_pos(),
+                      "generic function type '%s' not allowed as bound of "
+                      "function type parameter '%s'",
+                      type_name.ToCString(), type_param_name.ToCString());
+        }
+      }
     }
   }
   // Resolve result type.
@@ -1459,6 +1484,18 @@ void ClassFinalizer::ResolveUpperBounds(const Class& cls) {
     type_param ^= type_params.TypeAt(i);
     bound = type_param.bound();
     ResolveType(cls, bound);
+    if (bound.IsFunctionType()) {
+      const Function& signature_function =
+          Function::Handle(Type::Cast(bound).signature());
+      if (signature_function.IsGeneric()) {
+        const String& bound_name = String::Handle(bound.UserVisibleName());
+        const String& type_param_name = String::Handle(type_param.name());
+        ReportError(cls, bound.token_pos(),
+                    "generic function type '%s' not allowed as bound of "
+                    "class type parameter '%s'",
+                    bound_name.ToCString(), type_param_name.ToCString());
+      }
+    }
   }
 }
 

tests/language_2/generic_methods_generic_function_result_test.dart

@@ -4,19 +4,25 @@
 //
 // VMOptions=--generic-method-syntax,--error-on-bad-type
 
-// Verify that function type parameter S can be resolved in bar.
+// Verify that function type parameter S can be resolved in bar's result type.
+// Verify that generic function types are not allowed as type arguments.
 
 import "package:expect/expect.dart";
 
-T foo<T extends num>(int i, T t) => i + t;
+int foo
+       <T>  //# 01: continued
+          (int i, int j) => i + j;
 
-List<T Function<T extends num>(S, T)> bar<S extends int>() {
-  return <T Function<T extends num>(S, T)>[foo, foo];
+List<int Function
+                 <T>  //# 01: compile-time error
+                    (S, int)> bar<S extends int>() {
+  return <int Function
+                      <T>  //# 01: continued
+                         (S, int)>[foo, foo];
 }
 
 void main() {
   var list = bar<int>();
-  print(list[0]
-      .runtimeType); // "<T extends num>(int, T) => T" when reifying generic functions.
+  print(list[0].runtimeType);
   Expect.equals(123, list[1]<int>(100, 23));
 }

tests/language_2/language_2.status

@@ -37,8 +37,11 @@ accessor_conflict_import_prefixed2_test: StaticWarning # Issue 25626
 accessor_conflict_import_prefixed_test: StaticWarning # Issue 25626
 accessor_conflict_import_test: StaticWarning # Issue 25626
 
+[ $compiler == dart2analyzer && ! $strong ]
+generic_methods_generic_function_result_test/01: MissingCompileTimeError # Issue #30207
+
 [ $compiler == dart2analyzer && $strong ]
-generic_methods_generic_function_result_test: CompileTimeError # Issue #30207
+generic_methods_generic_function_result_test/none: CompileTimeError # Issue #30207
 
 [ $compiler == dart2js || $compiler == dartk || $compiler == dartdevc ]
-generic_methods_generic_function_result_test: CompileTimeError # Issue #30208
+generic_methods_generic_function_result_test/none: CompileTimeError # Issue #30208