[cfe-dev] Get underlying type of QualType if it's TypedefType

[陳韋任 via cfe-dev]

Hi All,

  I have SrcType and DestType used in explicit cast, and I'd like to check
if the type conversion is valid in CastOperation::CheckCStyleCast [1]. The
code snippet below (just get the idea, the code is not runable),

    Builtin *Src   = dyn_cast<BuiltinType>(SrcExpr.get()->getType());
    Builtin *Dest = dyn_cast<BuiltinType>(DestType);

    if (Src.getKind() == Dest.getKind()) {
      // do something
    } else {
      // do something else
    }

The problem is the SrcType and DestType might be typedef. For example,

    typedef foo FOO;

    FOO b = (FOO)(a);

Src and Dest might be nullptr due to the fail dyn_cast, and I will get
segfault while calling getKind() upon them.
I am not familiar with Clang, so is there a better way that I can get the
underlying type if SrcType and DestType
are typedef?

Thanks.

[1] https://clang.llvm.org/doxygen/SemaCast_8cpp_source.html

Regards,
chenwj

--
Wei-Ren Chen (陳韋任)
Homepage: https://people.cs.nctu.edu.tw/~chenwj
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