Commit d462aa5a authored by Adam Czachorowski's avatar Adam Czachorowski
Browse files

[clang] Fix a nullptr dereference bug on invalid code 

When working with invalid code, we would try to dereference a nullptr
while deducing template arguments in some dependend code operating on a
lambda with invalid return type.

Differential Revision: https://reviews.llvm.org/D95145
parent 68eee55c

clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

+3 −0
Original line number Diff line number Diff line
@@ -4189,6 +4189,9 @@ TemplateDeclInstantiator::SubstFunctionType(FunctionDecl *D, 
      for (unsigned OldIdx = 0, NumOldParams = OldProtoLoc.getNumParams();

           OldIdx != NumOldParams; ++OldIdx) {

        ParmVarDecl *OldParam = OldProtoLoc.getParam(OldIdx);

        if (!OldParam)

          return nullptr;



        LocalInstantiationScope *Scope = SemaRef.CurrentInstantiationScope;



        Optional<unsigned> NumArgumentsInExpansion;

clang/test/SemaCXX/subst-func-type-invalid-ret-type.cpp

0 → 100644
+16 −0
Original line number Diff line number Diff line 
// RUN: %clang -fsyntax-only -std=c++17 %s -Xclang -verify



// The important part is that we do not crash.



template<typename T> T declval();



template <typename T>

auto Call(T x) -> decltype(declval<T>()(0)) {} // expected-note{{candidate template ignored}}



class Status {};



void fun() {

  // The Status() (instead of Status) here used to cause a crash.

  Call([](auto x) -> Status() {}); // expected-error{{function cannot return function type 'Status ()}}

  // expected-error@-1{{no matching function for call to 'Call'}}

}