Only parse the directives when rewriting imports.

pkg/analyzer/lib/analyzer.dart

Index: pkg/analyzer/lib/analyzer.dart
diff --git a/pkg/analyzer/lib/analyzer.dart b/pkg/analyzer/lib/analyzer.dart
index fc9cfa11e3080626f3bb8446759a0869fb3481b9..0758cad7d7da287e9535d354ae83624f86ba907b 100644
--- a/pkg/analyzer/lib/analyzer.dart
+++ b/pkg/analyzer/lib/analyzer.dart
@@ -69,6 +69,30 @@ CompilationUnit parseCompilationUnit(String contents,
   return unit;
 }
 
+/// Parses the script tag and directives in a string of Dart code into an AST.
+///
+/// Stops parsing when the first non-directive is encountered. The rest of the
+/// string will not be parsed.
+///
+/// If [name] is passed, it's used in error messages as the name of the code
+/// being parsed.

[nweiz, 2014/06/03 21:23:09]

Document [suppressErrors] as well.

[Bob Nystrom, 2014/06/03 21:46:59]

Done.

+CompilationUnit parseDirectives(String contents,

[nweiz, 2014/06/03 21:23:09]

Probably a good idea to add a CHANGELOG entry about this.

[Bob Nystrom, 2014/06/03 21:46:59]

The analyzer package doesn't have a changelog.

[nweiz, 2014/06/03 23:06:57]

Great opportunity to add one :).

+    {String name, bool suppressErrors: false}) {
+  if (name == null) name = '<unknown source>';
+  var source = new StringSource(contents, name);
+  var errorCollector = new _ErrorCollector();
+  var reader = new CharSequenceReader(contents);
+  var scanner = new Scanner(source, reader, errorCollector);
+  var token = scanner.tokenize();
+  var parser = new Parser(source, errorCollector);
+  var unit = parser.parseDirectives(token);
+  unit.lineInfo = new LineInfo(scanner.lineStarts);
+
+  if (errorCollector.hasErrors && !suppressErrors) throw errorCollector.group;
+
+  return unit;
+}
+
 /// Converts an AST node representing a string literal into a [String].
 String stringLiteralToString(StringLiteral literal) {
   return literal.stringValue;