llvm-capstone/clang/test/SemaTemplate/operator-template.cpp
Matheus Izvekov c9e46219f3
[clang] retain type sugar in auto / template argument deduction
This implements the following changes:
* AutoType retains sugared deduced-as-type.
* Template argument deduction machinery analyses the sugared type all the way
down. It would previously lose the sugar on first recursion.
* Undeduced AutoType will be properly canonicalized, including the constraint
template arguments.
* Remove the decltype node created from the decltype(auto) deduction.

As a result, we start seeing sugared types in a lot more test cases,
including some which showed very unfriendly `type-parameter-*-*` types.

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Reviewed By: rsmith, #libc, ldionne

Differential Revision: https://reviews.llvm.org/D110216
2021-11-15 23:07:45 +01:00

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1.2 KiB
C++

// RUN: %clang_cc1 -fsyntax-only -verify -std=c++2a %s
// Make sure we accept this
template<class X>struct A{typedef X Y;};
template<class X>bool operator==(A<X>,typename A<X>::Y); // expected-note{{candidate template ignored: could not match 'A<X>' against 'B<int> *'}}
int a(A<int> x) { return operator==(x,1); }
int a0(A<int> x) { return x == 1; }
// FIXME: the location information for the note isn't very good
template<class X>struct B{typedef X Y;};
template<class X>bool operator==(B<X>*,typename B<X>::Y); // \
// expected-error{{overloaded 'operator==' must have at least one parameter of class or enumeration type}} \
// expected-note{{candidate template ignored: substitution failure [with X = int]}}
int a(B<int> x) { return operator==(&x,1); } // expected-error{{no matching function for call to 'operator=='}} \
// expected-note{{in instantiation of function template specialization}}
// Ensure we take parameter list reversal into account in partial oredring.
namespace CompareOrdering {
template<typename T> struct A {};
template<typename T> int operator<=>(A<T>, int) = delete;
template<typename T> int operator<=>(int, A<T*>);
// OK, selects the more-specialized reversed function.
bool b = A<int*>() < 0;
}