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Fix box/unbox of generic types #3237

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Merged
merged 3 commits into from
Nov 13, 2025
Merged

Fix box/unbox of generic types #3237

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d70ec58
Fix box/unbox of generic types
josesimoes Nov 12, 2025
bc3d263
Code style fixes
nfbot Nov 12, 2025
8e3dc27
Merge pull request #102 from nanoframework/nfbot/clang-format-fix/37a…
josesimoes Nov 12, 2025
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34 changes: 33 additions & 1 deletion src/CLR/Core/Interpreter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2905,7 +2905,28 @@ HRESULT CLR_RT_Thread::Execute_IL(CLR_RT_StackFrame &stackArg)
}
else
{
NANOCLR_CHECK_HRESULT(evalPos[0].PerformBoxing(typeInst));
// Check if we're trying to box a null reference for a reference type
// For generic types, the value might already be null (DATATYPE_OBJECT with null reference)
if (evalPos[0].DataType() == DATATYPE_OBJECT)
{
CLR_RT_HeapBlock *ptr = evalPos[0].Dereference();
if (ptr == nullptr)
{
// Already a null reference, no need to box
// Just ensure it stays as a null object reference
evalPos[0].SetObjectReference(nullptr);
}
else
{
// Non-null object reference, perform boxing
NANOCLR_CHECK_HRESULT(evalPos[0].PerformBoxing(typeInst));
}
}
else
{
// Value type or other type, perform normal boxing
NANOCLR_CHECK_HRESULT(evalPos[0].PerformBoxing(typeInst));
}
}
}
else
Expand Down Expand Up @@ -2947,6 +2968,17 @@ HRESULT CLR_RT_Thread::Execute_IL(CLR_RT_StackFrame &stackArg)
}
else
{
// Check if we're trying to unbox a null reference
if (evalPos[0].DataType() == DATATYPE_OBJECT)
{
CLR_RT_HeapBlock *ptr = evalPos[0].Dereference();
if (ptr == nullptr)
{
// Attempting to unbox a null reference throws NullReferenceException
NANOCLR_SET_AND_LEAVE(CLR_E_NULL_REFERENCE);
}
}

NANOCLR_CHECK_HRESULT(evalPos[0].PerformUnboxing(typeInst));
}
}
Expand Down