Change compile-time errors into dynamic errors in instance creation expression

runtime/vm/class_finalizer.cc

Index: runtime/vm/class_finalizer.cc
===================================================================
--- runtime/vm/class_finalizer.cc	(revision 13204)
+++ runtime/vm/class_finalizer.cc	(working copy)
@@ -746,6 +746,16 @@
       type_argument = arguments.TypeAt(i);
       type_argument = FinalizeType(cls, type_argument, finalization);
       if (type_argument.IsMalformed()) {
+        // Malformed type arguments to a constructor of a generic type are
+        // reported as a compile-time error.
+        if (finalization >= kCanonicalizeForCreation) {
+          const Script& script = Script::Handle(cls.script());
+          const String& type_name =
+              String::Handle(parameterized_type.UserVisibleName());
+          ReportError(script, parameterized_type.token_pos(),
+                      "type '%s' has malformed type argument",
+                      type_name.ToCString());
+        }
         // In production mode, malformed type arguments are mapped to Dynamic.
         // In checked mode, a type with malformed type arguments is malformed.
         if (FLAG_enable_type_checks || FLAG_error_on_malformed_type) {
@@ -775,6 +785,14 @@
   // However, type parameter bounds are checked below, even for a raw type.
   if (!arguments.IsNull() && (arguments.Length() != num_type_parameters)) {
     // Wrong number of type arguments. The type is malformed.
+    if (finalization >= kCanonicalizeForCreation) {
+      const Script& script = Script::Handle(cls.script());
+      const String& type_name =
+          String::Handle(parameterized_type.UserVisibleName());
+      ReportError(script, parameterized_type.token_pos(),
+                  "wrong number of type arguments in type '%s'",
+                  type_name.ToCString());
+    }
     FinalizeMalformedType(
         Error::Handle(),  // No previous error.
         cls, parameterized_type, finalization,