Implement fromEnvironment on bool, int, String in dart2js.

sdk/lib/_internal/compiler/implementation/inferrer/type_graph_nodes.dart

Index: sdk/lib/_internal/compiler/implementation/inferrer/type_graph_nodes.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/inferrer/type_graph_nodes.dart	(revision 29652)
+++ sdk/lib/_internal/compiler/implementation/inferrer/type_graph_nodes.dart	(working copy)
@@ -197,7 +197,7 @@
  * return type.
  *
  * Note that a few elements of these kinds must be treated specially,
- * and they are dealt in [ElementTypeInformation.handleSpecialCase]:
+ * and they are dealt in [ElementTypeInformation.handleSpecialCases]:
  *
  * - Parameters of closures, [noSuchMethod] and [call] instance
  *   methods: we currently do not infer types for those.
@@ -298,6 +298,17 @@
         }
       }
     }
+
+    Compiler compiler = inferrer.compiler;
+    if (element.declaration == compiler.intEnvironment) {
+      giveUp(inferrer);

[kasperl, 2013/10/31 09:11:51]

Why do you give up in the int and bool case, but not for strings? That at least
deserves a comment.

[ngeoffray, 2013/10/31 09:32:24]

Good catch. I should actually give up for the string case as well. Not giving up
will not make the analysis unsound, but will potentially analyze this node again
and again.

+      return compiler.typesTask.intType.nullable();
+    } else if (element.declaration == compiler.boolEnvironment) {
+      giveUp(inferrer);
+      return compiler.typesTask.boolType.nullable();
+    } else if (element.declaration == compiler.stringEnvironment) {
+      return compiler.typesTask.stringType.nullable();
+    }
     return null;
   }