Update assert to follow the spec.

compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java

Index: compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java
===================================================================
--- compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java	(revision 409)
+++ compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java	(working copy)
@@ -636,7 +636,6 @@
           checkAssignable(conditionNode, boolType, condition);

[jat, 2011/10/13 21:03:01]

I know this is pre-existing code, but it seems like this isn't going to properly
handle something like:

var x = () => true;
assert(x);

I don't think we can rely on statically knowing the argument is a function for
this type check.  If you don't want to address it as part of this, please file
an issue to investigate/fix it later.

[ahe, 2011/10/13 21:19:41]

What is it you think is wrong here? This is the *static* type analyzer.

I tried your example: http://try.dartlang.org/s/TjUa and there are no type
errors. There is an unexpected NullPointerException, so perhaps John should add
this test case.

[jat, 2011/10/13 21:21:52]

Ok, so if the type isn't known, checkAssignable will just ignore it?  If so,
that's fine.

[John Lenz, 2011/10/13 21:35:43]

I think that should be fine.  x is dynamic and therefore assignable to bool.
Added a testcase.

           break;
       }
-      checkAssignable(stringType, node.getMessage());
       return voidType;
     }