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[c++17] When deducing the type of a non-type template parameter from the type 

of its argument, perform function-to-pointer and array-to-pointer decay on the
parameter type first.

Otherwise deduction will fail, as the type of the argument will be decayed.

llvm-svn: 319584
This commit is contained in:
Richard Smith 2017-12-01 21:24:36 +00:00
parent 6260cf71d3
commit 7bfcc05830
2 changed files with 7 additions and 2 deletions
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5
clang/lib/Sema/SemaTemplateDeduction.cpp
View File

@ -354,8 +354,9 @@ static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
// expanded NTTP should be a pack expansion type?
return Sema::TDK_Success;
// Get the type of the parameter for deduction.
QualType ParamType = NTTP->getType();
// Get the type of the parameter for deduction. If it's a (dependent) array
// or function type, we will not have decayed it yet, so do that now.
QualType ParamType = S.Context.getAdjustedParameterType(NTTP->getType());
if (auto *Expansion = dyn_cast<PackExpansionType>(ParamType))
ParamType = Expansion->getPattern();

4
clang/test/SemaTemplate/temp_arg_nontype_cxx1z.cpp
View File

@ -238,6 +238,10 @@ namespace Auto {
constexpr char s[] = "test";
template<const auto* p> struct S { };
S<s> p;
template<typename R, typename P, R F(P)> struct A {};
template<typename R, typename P, R F(P)> void x(A<R, P, F> a);
void g(int) { x(A<void, int, &g>()); }
}
namespace DecltypeAuto {