Provide better debugging if a null type is encountered.

Provide better debugging if a null type is encountered.

Patches up at least one case where the 'this' keyword could return null if used in a static context.

http://code.google.com/p/dart/issues/detail?id=761

Committed: https://code.google.com/p/dart/source/detail?r=3564

[zundel, 2012-01-23 21:25:27]

Issue 761 has a stack trace caused by a null type being returned from somewhere
in the TypeAnalyzer.  I am taking the position that no visit should return null.
 Seeing as I can't reproduce the error, I added a few places to coerce the type
to 'dynamic' or 'void' and then added null tests to throw an internal exception
if a null type is encountered.  

I don't really like adding runtime null checks, but currently the place that
throws the error might be very far from where the node where the null type was
returned.

[codefu, 2012-01-23 21:48:53]

lgtm + nits

https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
File compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java (right):

https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:621: 
extra ws?

https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:1331: if (type ==
null) {
What about replacing the other if(null){throw) with:
type.getClass(); // Quick null check.

[scheglov, 2012-01-23 21:49:25]

lgtm

https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
File compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java (right):

https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:558: Type
argumentType = argumentTypes.next();
assert argumentType != null;  ?
assert namedEntry.getValue() != null;  ?

https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:579: Type
argumentType = argumentTypes.next();
assert argumentType != null;  ?
Hm... and may be push this line into "else" block.

[zundel, 2012-01-23 22:33:35]

PTAL

https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
File compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java (right):

https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:558: Type
argumentType = argumentTypes.next();
On 2012/01/23 21:49:25, scheglov wrote:
> assert argumentType != null;  ?
> assert namedEntry.getValue() != null;  ?

Done.

https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:579: Type
argumentType = argumentTypes.next();
On 2012/01/23 21:49:25, scheglov wrote:
> assert argumentType != null;  ?
> Hm... and may be push this line into "else" block.
I don't think we can move this line because we always need to increment through
the iterator.

I updated the code, but I'm not 100% sure what you meant by move this line.

https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:1331: if (type ==
null) {
On 2012/01/23 21:48:53, codefu wrote:
> What about replacing the other if(null){throw) with:
> type.getClass(); // Quick null check.

Done.

[scheglov, 2012-01-24 19:05:02]

LGTM

http://codereview.chromium.org/9160004/diff/2003/compiler/java/com/google/dar...
File compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java (right):

http://codereview.chromium.org/9160004/diff/2003/compiler/java/com/google/dar...
compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:534:
argumentType.getClass();
no "quick null check" comment

http://codereview.chromium.org/9160004/diff/2003/compiler/java/com/google/dar...
compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:608:
type.getClass(); // fast null check
was "quick null check" above

[codefu, 2012-01-24 19:08:14]

still LGTM
On 2012/01/23 22:33:35, zundel wrote:
> PTAL
> 
>
https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
> File compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java (right):
> 
>
https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
> compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:558: Type
> argumentType = argumentTypes.next();
> On 2012/01/23 21:49:25, scheglov wrote:
> > assert argumentType != null;  ?
> > assert namedEntry.getValue() != null;  ?
> 
> Done.
> 
>
https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
> compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:579: Type
> argumentType = argumentTypes.next();
> On 2012/01/23 21:49:25, scheglov wrote:
> > assert argumentType != null;  ?
> > Hm... and may be push this line into "else" block.
> I don't think we can move this line because we always need to increment
through
> the iterator.
> 
> I updated the code, but I'm not 100% sure what you meant by move this line.
> 
>
https://chromiumcodereview.appspot.com/9160004/diff/1/compiler/java/com/googl...
> compiler/java/com/google/dart/compiler/type/TypeAnalyzer.java:1331: if (type
==
> null) {
> On 2012/01/23 21:48:53, codefu wrote:
> > What about replacing the other if(null){throw) with:
> > type.getClass(); // Quick null check.
> 
> Done.