CXCursor.LambdaContextDecl cause AccessViolationException

[phizch]

When the LambdaContextDecl property on a CXCursor that represents a CXXRecordDecl invalid memory might be accessed

Cause:

An assert raised in libClang.
see:
https://github.com/llvm/llvm-project/blob/ef4ffcafbb2deeb30ccc30ebcdf9a5a843a27ec1/clang/lib/AST/DeclCXX.cpp#L1534-L1538

If CXXRecordDecl::isLambda() is false an assert is caused, which somehow writes to invalid memory.

Solution:

Check CXXRecordDecl::isLambda() before accessing CXXRecordDecl::getLambdaContextDecl()

 CXCursor clangsharp_Cursor_getLambdaContextDecl(CXCursor C) { 
     if (clang_isDeclaration(C.kind)) { 
         const Decl* D = getCursorDecl(C); 
  
         if (const CXXRecordDecl* CRD = dyn_cast<CXXRecordDecl>(D)) { 
            if( CRD->isLambda() )
                return MakeCXCursor(CRD->getLambdaContextDecl(), getCursorTU(C));
         } 
     } 
  
     return clang_getNullCursor(); 
 } 

I've implemented the change and it fixed the problem.

Source location:

https://github.com/microsoft/ClangSharp/blob/2e4f410e6c065a2e51b54889f202b61c3c4a5438/sources/libClangSharp/ClangSharp.cpp#L1690-L1700

[tannergooding]

This was resolved in #185