Start implementing checked mode and tools support for using it.

lib/compiler/implementation/apiimpl.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('leg_apiimpl');
 
 #import('dart:uri');
 
 #import('../compiler.dart', prefix: 'api');
 #import('leg.dart', prefix: 'leg');
 #import('tree/tree.dart', prefix: 'tree');
 #import('elements/elements.dart', prefix: 'elements');
 #import('ssa/tracer.dart', prefix: 'ssa');
 #import('library_map.dart');
 #import('source_file.dart');
 
 class Compiler extends leg.Compiler {
   api.ReadUriFromString provider;
   api.DiagnosticHandler handler;
   Uri libraryRoot;
   Uri packageRoot;
   List<String> options;
   bool mockableLibraryUsed = false;
+  bool checkedMode = false;

[ahe, 2012/05/07 11:59:57]

Developer mode, please.

[ngeoffray, 2012/05/07 13:15:42]

Renamed to enableTypeAssertions.

 
   Compiler(this.provider, this.handler, this.libraryRoot, this.options)
-    : super(tracer: new ssa.HTracer());
+    : super(tracer: new ssa.HTracer()) {
+    checkedMode = options.indexOf('--enable-checked-mode') !== -1;

[ahe, 2012/05/07 11:59:57]

I don't like this flag name. I think it should be something like:

--developer-mode

I'm fine having aliases for compatibility with the VM. But I think we need to
*think* about flag names, instead of just doing something. This is the most
fundamental interface to the compiler, and it should be "designed".

[ngeoffray, 2012/05/07 13:15:42]

As discussed, keeping enable-checked-mode only for now.

+  }
 
   elements.LibraryElement scanBuiltinLibrary(String path) {
     Uri uri = libraryRoot.resolve(DART2JS_LIBRARY_MAP[path]);
     elements.LibraryElement library = scanner.loadLibrary(uri, null);
     return library;
   }
 
   void log(message) {
     handler(null, null, null, message, false);
   }
@@ skipping 51 matching lines @@
       handler(null, null, null, message, fatal);
     } else {
       handler(span.uri, span.begin, span.end, message, fatal);
     }
   }
 
   bool get isMockCompilation() {
     return mockableLibraryUsed
       && (options.indexOf('--allow-mock-compilation') !== -1);
   }
+
+  bool get isCheckedModeEnabled() {

[ahe, 2012/05/07 11:59:57]

Developer mode, please.

[ngeoffray, 2012/05/07 13:15:42]

I removed the getter.

+    return checkedMode;
+  }
 }