Use FastaMessage instead of String. Part 1.

pkg/front_end/lib/src/fasta/builder/library_builder.dart

Index: pkg/front_end/lib/src/fasta/builder/library_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/builder/library_builder.dart b/pkg/front_end/lib/src/fasta/builder/library_builder.dart
index 6e0aa2e178056f3537156b339d6c893b942e36e0..b69cbbdc201c0a75feb554bb55b8f66d00c6c62c 100644
--- a/pkg/front_end/lib/src/fasta/builder/library_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/library_builder.dart
@@ -12,7 +12,8 @@ import '../export.dart' show Export;
 
 import '../loader.dart' show Loader;
 
-import '../messages.dart' show deprecated_nit, deprecated_warning;
+import '../messages.dart'
+    show BoundFastaMessage, deprecated_nit, deprecated_warning, nit, warning;
 
 import '../util/relativize.dart' show relativizeUri;
 
@@ -77,6 +78,27 @@ abstract class LibraryBuilder<T extends TypeBuilder, R> extends Builder {
         silent: silent, wasHandled: wasHandled);
   }
 
+  void addCompileTimeError(BoundFastaMessage bind, int charOffset, Uri uri,

[Siggi Cherem (dart-lang), 2017/07/07 21:17:08]

I feel we are are overloading the term `bind`:

  * bind in UnboundFastaCode converts unbound-code to produce a bound-message
  * bind here converts a bound-message to a message with location

A small fix would be to use a different variable name here, like "message", but
I think it is a confusing name to use as a function target.

I believe it makes sense to do some broader renames of the types. One option is
to rename "BoundFastaMessage" to something that is more like a verb like
"FastaMessageCreator" and use a variable name that implies the action (e.g.
"generateMessage"). But I feel things will get cleaner if we represent
`BoundFastaMessage` as an object and not a function.  I made a more detailed
suggestion in fasta_codes.dart, take a look there.

[ahe, 2017/07/10 13:43:50]

I agree.

+      {bool silent: false, bool wasHandled: false}) {
+    deprecated_addCompileTimeError(
+        charOffset, bind(fileUri, charOffset).message,
+        fileUri: uri, silent: silent, wasHandled: wasHandled);
+  }
+
+  void addWarning(BoundFastaMessage bind, int charOffset, Uri uri,
+      {bool silent: false}) {
+    if (!silent) {
+      warning(bind(uri, charOffset));
+    }
+  }
+
+  void addNit(BoundFastaMessage bind, int charOffset, Uri uri,
+      {bool silent: false}) {
+    if (!silent) {
+      nit(bind(uri, charOffset));
+    }
+  }
+
   void deprecated_addWarning(int charOffset, Object message,
       {Uri fileUri, bool silent: false}) {
     fileUri ??= this.fileUri;