Ensure that no scripts are resolved when compiling purely from deserialized data.

pkg/compiler/lib/src/compiler.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.compiler_base;
 
 import 'dart:async' show EventSink, Future;
 
 import '../compiler_new.dart' as api;
 import 'cache_strategy.dart' show CacheStrategy;
@@ skipping 304 matching lines @@
           '--dump-info is not supported with the fast startup emitter');
     }
 
     tasks = [
       dietParser =
           new DietParserTask(options, idGenerator, backend, reporter, measurer),
       scanner = createScannerTask(),
       serialization = new SerializationTask(this),
       libraryLoader = new LibraryLoaderTask(
           resolvedUriTranslator,
-          new _ScriptLoader(this),
+          options.compileOnly
+              ? new _NoScriptLoader(this) : new _ScriptLoader(this),
           new _ElementScanner(scanner),
           serialization,
           this,
           environment,
           reporter,
           measurer),
       parser = new ParserTask(this, options),
       patchParser = new PatchParserTask(this, options),
       resolver = createResolverTask(),
       closureToClassMapper = new closureMapping.ClosureTask(this),
@@ skipping 1822 matching lines @@
 }
 
 class _ScriptLoader implements ScriptLoader {
   Compiler compiler;
   _ScriptLoader(this.compiler);
 
   Future<Script> readScript(Uri uri, [Spannable spannable]) =>
       compiler.readScript(uri, spannable);
 }
 
+/// [ScriptLoader] used to ensure that scripts are not loaded accidentally
+/// through the [LibraryLoader] when `CompilerOptions.compileOnly` is `true`.
+class _NoScriptLoader implements ScriptLoader {
+  Compiler compiler;
+  _NoScriptLoader(this.compiler);
+
+  Future<Script> readScript(Uri uri, [Spannable spannable]) {
+    compiler.reporter.internalError(spannable,
+        "Script loading of '$uri' is not enabled.");
+  }
+}
+
 class _ElementScanner implements ElementScanner {
   ScannerTask scanner;
   _ElementScanner(this.scanner);
   void scanLibrary(LibraryElement library) => scanner.scanLibrary(library);
   void scanUnit(CompilationUnitElement unit) => scanner.scan(unit);
 }
 
 class _EmptyEnvironment implements Environment {
   const _EmptyEnvironment();
 
   String valueOf(String key) => null;
 }