SemaObjC::HandleExprPropertyRefExpr assumes getInterfaceType() will never return nullptr

[shafik]

Static analysis has flagged, this line in SemaObjC::HandleExprPropertyRefExpr:

llvm-project/clang/lib/Sema/SemaExprObjC.cpp

Lines 1982 to 1983 in ab95005

	const ObjCInterfaceType *IFaceT = OPT->getInterfaceType();
	ObjCInterfaceDecl *IFace = IFaceT->getDecl();

as possibly returning nullptr which would make the subsequent access of IFaceT->getDecl(); UB.

Based on the documentation:

llvm-project/clang/lib/Sema/SemaExprObjC.cpp

Lines 1975 to 1976 in ab95005

	/// HandleExprPropertyRefExpr - Handle foo.bar where foo is a pointer to an
	/// objective C interface. This is a property reference expression.

and the rest of the code it seems clear that the assumption is that it will always be valid.

We could document more clearly w/ an assertion on IFaceT.

[shafik]

CC @rjmccall does this look like the right path?

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Shafik Yaghmour (shafik)

Static analysis has flagged, this line in `SemaObjC::HandleExprPropertyRefExpr`:

llvm-project/clang/lib/Sema/SemaExprObjC.cpp

Lines 1982 to 1983 in ab95005

	const ObjCInterfaceType *IFaceT = OPT->getInterfaceType();
	ObjCInterfaceDecl *IFace = IFaceT->getDecl();

as possibly returning nullptr which would make the subsequent access of IFaceT->getDecl(); UB.

Based on the documentation:

llvm-project/clang/lib/Sema/SemaExprObjC.cpp

Lines 1975 to 1976 in ab95005

	/// HandleExprPropertyRefExpr - Handle foo.bar where foo is a pointer to an
	/// objective C interface. This is a property reference expression.

and the rest of the code it seems clear that the assumption is that it will always be valid.

We could document more clearly w/ an assertion on IFaceT.

[shafik]

ping @rjmccall