Files
icsharpcode-ILSpy/ICSharpCode.Decompiler.Tests/TestCases/VBPretty/Issue3659.cs
T
dualfroz b5ad0ac820 Recognize a VB exception filter's type test
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 #3659
2026-09-15 19:16:29 +02:00

92 lines
1.6 KiB
C#

using System;
using System.Runtime.CompilerServices;
using Microsoft.VisualBasic.CompilerServices;
public class Issue3659
{
public static void Func(ref Issue3659 obj, object value)
{
}
public static int ShowMessage(string a, int b, string c, object d, int e)
{
return 0;
}
internal void VBFunction(object value)
{
#if OPT || LEGACY_VBC
int try0000_dispatch = -1;
#else
int try0001_dispatch = -1;
#endif
int num2 = default;
int num = default;
while (true)
{
try
{
/*Note: ILSpy has introduced the following switch to emulate a goto from catch-block to try-block*/;
#if OPT || LEGACY_VBC
switch (try0000_dispatch)
#else
switch (try0001_dispatch)
#endif
{
default:
{
ProjectData.ClearProjectError();
num2 = 2;
Issue3659 obj = this;
Func(ref obj, RuntimeHelpers.GetObjectValue(value));
#if OPT || LEGACY_VBC
goto end_IL_0000;
#else
goto end_IL_0001;
#endif
}
#if OPT || LEGACY_VBC
case 45:
#else
case 50:
#endif
num = -1;
switch (num2)
{
case 2:
ShowMessage("VBFunction", 0, "Exception", null, 0);
#if OPT || LEGACY_VBC
goto end_IL_0000;
#else
goto end_IL_0001;
#endif
}
break;
}
}
catch (Exception ex) when ((num2 != 0) & (num == 0))
{
ProjectData.SetProjectError(ex);
#if OPT || LEGACY_VBC
try0000_dispatch = 45;
#else
try0001_dispatch = 50;
#endif
continue;
}
throw ProjectData.CreateProjectError(-2146828237);
continue;
#if OPT || LEGACY_VBC
end_IL_0000:
#else
end_IL_0001:
#endif
break;
}
if (num != 0)
{
ProjectData.ClearProjectError();
}
}
}