Bug 8623 - Debugger often doesn't display Locals due to NRE in Mono.Debugging.Evaluation.EvaluatorVisitor
Summary: Debugger often doesn't display Locals due to NRE in Mono.Debugging.Evaluation...
Status: RESOLVED INVALID
Alias: None
Product: Xamarin Studio
Classification: Desktop
Component: Debugger ()
Version: Trunk
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: ---
Assignee: Jeffrey Stedfast
URL:
Depends on:
Blocks:
 
Reported: 2012-11-27 17:18 UTC by Frank A. Krueger
Modified: 2013-11-19 19:24 UTC (History)
3 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED INVALID

Description Frank A. Krueger 2012-11-27 17:18:30 UTC
Locals don't display because the debugger keeps crashing with this exception:

System.NullReferenceException: Object reference not set to an instance of an object
  at Mono.Debugging.Evaluation.EvaluatorVisitor.EvaluateBinaryOperatorExpression (Mono.Debugging.Evaluation.ValueReference left, ICSharpCode.OldNRefactory.Ast.Expression rightExp, BinaryOperatorType oper, System.Object data) [0x0015f] in /Users/builder/data/lanes/monodevelop_private-lion-ui-refresh/39bc312c/source/monodevelop/main/src/core/Mono.Debugging/Mono.Debugging.Evaluation/NRefactoryEvaluator.cs:842 
  at Mono.Debugging.Evaluation.EvaluatorVisitor.VisitBinaryOperatorExpression (ICSharpCode.OldNRefactory.Ast.BinaryOperatorExpression binaryOperatorExpression, System.Object data) [0x00013] in /Users/builder/data/lanes/monodevelop_private-lion-ui-refresh/39bc312c/source/monodevelop/main/src/core/Mono.Debugging/Mono.Debugging.Evaluation/NRefactoryEvaluator.cs:658 
  at ICSharpCode.OldNRefactory.Ast.BinaryOperatorExpression.AcceptVisitor (IAstVisitor visitor, System.Object data) [0x00000] in /Users/builder/data/lanes/monodevelop_private-lion-ui-refresh/39bc312c/source/monodevelop/main/contrib/NRefactory/Project/Src/Ast/Generated.cs:455 
  at Mono.Debugging.Evaluation.EvaluatorVisitor.VisitBinaryOperatorExpression (ICSharpCode.OldNRefactory.Ast.BinaryOperatorExpression binaryOperatorExpression, System.Object data) [0x00000] in /Users/builder/data/lanes/monodevelop_private-lion-ui-refresh/39bc312c/source/monodevelop/main/src/core/Mono.Debugging/Mono.Debugging.Evaluation/NRefactoryEvaluator.cs:657 
  at ICSharpCode.OldNRefactory.Ast.BinaryOperatorExpression.AcceptVisitor (IAstVisitor visitor, System.Object data) [0x00000] in /Users/builder/data/lanes/monodevelop_private-lion-ui-refresh/39bc312c/source/monodevelop/main/contrib/NRefactory/Project/Src/Ast/Generated.cs:455 
  at Mono.Debugging.Evaluation.NRefactoryEvaluator.Evaluate (Mono.Debugging.Evaluation.EvaluationContext ctx, System.String exp, System.Object expectedType, Boolean tryTypeOf) [0x00164] in /Users/builder/data/lanes/monodevelop_private-lion-ui-refresh/39bc312c/source/monodevelop/main/src/core/Mono.Debugging/Mono.Debugging.Evaluation/NRefactoryEvaluator.cs:90
Comment 1 Jeffrey Stedfast 2012-12-07 16:40:10 UTC
Bojan had a similar problem but wasn't reliably able to reproduce this.

Do you have a reliable repro case? Near as I could tell, it had to do with being unable to resolve the right-hand operand.

In order to debug this, I'll need an expression that causes this to happen :-\
Comment 2 PJ 2013-11-19 17:05:43 UTC
This bug has been in the NEEDINFO state with no changes for the last 90 days. Can we put this back into the NEW or CONFIRMED state, or are we still awaiting response?

If there is no change in the status of this bug over the next two weeks, this bug will be marked as NORESPONSE.
Comment 3 Frank A. Krueger 2013-11-19 19:17:41 UTC
I haven't encountered this error in awhile so marked this as resolved.
Comment 4 Bojan Rajkovic [MSFT] 2013-11-19 19:24:53 UTC
Ditto.