Index: lib/Sema/SemaTemplate.cpp =================================================================== --- lib/Sema/SemaTemplate.cpp +++ lib/Sema/SemaTemplate.cpp @@ -974,7 +974,7 @@ QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI, SourceLocation Loc) { if (TSI->getType()->isUndeducedType()) { - // C++1z [temp.dep.expr]p3: + // C++17 [temp.dep.expr]p3: // An id-expression is type-dependent if it contains // - an identifier associated by name lookup with a non-type // template-parameter declared with a type that contains a @@ -9866,6 +9866,15 @@ if (!NewTSI) return true; + if (NewTSI->getType()->isUndeducedType()) { + // C++17 [temp.dep.expr]p3: + // An id-expression is type-dependent if it contains + // - an identifier associated by name lookup with a non-type + // template-parameter declared with a type that contains a + // placeholder type (7.1.7.4), + NewTSI = SubstAutoTypeSourceInfo(NewTSI, Context.DependentTy); + } + if (NewTSI != NTTP->getTypeSourceInfo()) { NTTP->setTypeSourceInfo(NewTSI); NTTP->setType(NewTSI->getType()); Index: test/SemaTemplate/temp_arg_nontype_cxx1z.cpp =================================================================== --- test/SemaTemplate/temp_arg_nontype_cxx1z.cpp +++ test/SemaTemplate/temp_arg_nontype_cxx1z.cpp @@ -335,3 +335,46 @@ void g(int, int); using Int = A::B<&g>::param2; } + +namespace rdar41852459 { +template struct G {}; + +template struct S { + template void f() { + G x; + } + template void f2() { + G x; + } + template void f3() { + G x; + } +}; + +template struct I {}; + +template struct K { + template void f() { + I x; + } + template void f2() { + I x; + } + template void f3() { + I x; + } +}; + +template struct L {}; +template struct M { + template void f() { + L x; + } + template void f() { + L x; + } + template void f() { + L x; + } +}; +}