Extend pkg/front_end/lib/src/fasta/kernel/verifier.dart to check for UnknownType.

pkg/front_end/lib/src/fasta/kernel/verifier.dart

Index: pkg/front_end/lib/src/fasta/kernel/verifier.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/verifier.dart b/pkg/front_end/lib/src/fasta/kernel/verifier.dart
index 57114240103d75efc51f2b8cca5dfb1fce79f612..291656ef6afc7ed0a12a2b29a75e0b5dcc24d268 100644
--- a/pkg/front_end/lib/src/fasta/kernel/verifier.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/verifier.dart
@@ -4,6 +4,9 @@
 
 library fasta.verifier;
 
+import 'package:front_end/src/fasta/type_inference/type_schema.dart'
+    show TypeSchemaVisitor, UnknownType;
+
 import 'package:kernel/ast.dart'
     show
         InvalidExpression,
@@ -30,7 +33,8 @@ List<VerificationError> verifyProgram(Program program,
   return verifier.errors;
 }
 
-class FastaVerifyingVisitor extends VerifyingVisitor {
+class FastaVerifyingVisitor extends VerifyingVisitor
+    implements TypeSchemaVisitor {
   final List<VerificationError> errors = <VerificationError>[];
 
   String fileUri;
@@ -42,7 +46,7 @@ class FastaVerifyingVisitor extends VerifyingVisitor {
   @override
   problem(TreeNode node, String details) {
     VerificationError error = new VerificationError(context, node, details);
-    printUnexpected(Uri.parse(fileUri), node.fileOffset, "$error");
+    printUnexpected(Uri.parse(fileUri), node?.fileOffset ?? 0, "$error");

[ahe, 2017/04/27 16:38:20]

-1.

[Paul Berry, 2017/04/27 16:43:51]

Done.

     errors.add(error);
   }
 
@@ -93,4 +97,10 @@ class FastaVerifyingVisitor extends VerifyingVisitor {
   visitInvalidInitializer(InvalidInitializer node) {
     problem(node, "Invalid initializer.");
   }
+
+  @override
+  visitUnknownType(UnknownType node) {
+    // Note: we can't pass [node] to [problem] because it's not a [TreeNode].
+    problem(null, "Unexpected appearance of the unknown type.");
+  }
 }