Recognize a VB exception filter's type test - #4134
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vbc builds an exception filter as a single non-short-circuiting
expression: `isinst`, then the user's `when` conditions, combined with
`and`. DetectCatchWhenConditionBlocks only knew the branch chain csc
emits, so the type test stayed inside the filter and the handler kept the
`object` variable it has in IL:
catch (object obj) when ((obj is Exception) & (num2 != 0) & (num == 0))
{
ProjectData.SetProjectError((Exception)obj);
A catch type has to derive from Exception, so that does not compile.
The conjunction form is matched too now, lifting the test to the catch
type as the block form already does. The other conjuncts stop running for
a non-matching exception once the test moves, so the filter has to be
pure for this to be invisible; PropagateExceptionVariable then drops the
castclass in the handler:
catch (Exception ex) when ((num2 != 0) & (num == 0))
{
ProjectData.SetProjectError(ex);
Closes icsharpcode#3659
Member
|
Did you use AI to implement this? Please read https://github.com/icsharpcode/ILSpy/blob/master/CONTRIBUTING.md#contributing especially bullet 2. |
| @@ -0,0 +1,109 @@ | |||
| .assembly extern System.Runtime | |||
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Why not make this a VBPretty test?
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Yeah, my bad. Will change that in a sec
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should be done, sorry, won't happen again
Author
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Hi. I didn't use the AI to write the code itself. I did however use AI to make it easier to read. Same with the comment - i wrote it myself and then told ai to please make it look nicer |
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vbc emits a filter as one
andexpression rather than the branch chain csc emits, so VB filters decompiled tocatch (object obj).That form is now matched and becomes
catch (Exception ex) when (...), but only when the whole filter is pure, since moving the type test changes evaluation order.Closes #3659