[kernel] Make fasta call a new constructor on FallThroughError

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

Index: pkg/front_end/lib/src/fasta/kernel/body_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
index 29a33e122ee900d8d126d359dbbdc386371d7203..9771fe92249c6253023d70f7bd909545afb7770e 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
@@ -40,6 +40,8 @@ import 'package:kernel/core_types.dart' show CoreTypes;
 
 import 'frontend_accessors.dart' show buildIsNull, makeBinary, makeLet;
 
+import '../messages.dart' as messages;

[ahe, 2017/06/19 14:33:06]

import '../messages.dart' show getLocationFromUri;

[jensj, 2017/06/20 11:24:49]

Done.

+
 import '../../scanner/token.dart' show BeginToken, Token;
 
 import '../scanner/token.dart' show isBinaryOperator, isMinusOperator;
@@ -2996,9 +2998,16 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
 
   Expression buildFallThroughError(int charOffset) {
     warningNotError("Switch case may fall through to next case.", charOffset);
-    Builder constructor = library.loader.getFallThroughError();

[ahe, 2017/06/19 14:33:06]

Would you mind removing all the getFallThroughError methods in
pkg/front_end/lib/src/fasta/...?

[jensj, 2017/06/20 11:24:48]

Done.

+
+    Location location =
+        charOffset >= 0 ? messages.getLocationFromUri(uri, charOffset) : null;

[ahe, 2017/06/19 14:33:06]

Call this unconditionally.

[jensj, 2017/06/20 11:24:49]

Done.

+
     return new Throw(buildStaticInvocation(
-        constructor.target, new Arguments.empty(),
+        library.loader.coreTypes.fallThroughErrorUrlAndLineConstructor,
+        new Arguments(<Expression>[
+          new StringLiteral(location?.file ?? uri.toString()),
+          new IntLiteral(location?.line ?? 0)
+        ]),
         charOffset: charOffset));
   }