[clang] [Clang] Clarify diagnostic notes for implcitly generated deduction guides (PR #96084)
Younan Zhang via cfe-commits
cfe-commits at lists.llvm.org
Wed Jun 19 08:43:17 PDT 2024
https://github.com/zyn0217 created https://github.com/llvm/llvm-project/pull/96084
Given the following invalid code,
```cpp
template <class T>
struct S {
T *a;
};
S s = {1};
```
we produce such diagnostics currently:
```
<source>:2:8: note: candidate template ignored: could not match 'S<T>' against 'int'
2 | struct S {
| ^
<source>:2:8: note: candidate template ignored: could not match 'T *' against 'int'
```
Which I think is confusing because there's no `S<T>` nor `T *` at the location it points to. This is because we're deducing the initializer against implicitly generated deduction guides, and their source locations just point to the corresponding `RecordDecl`. And hence the misleading notes.
This patch alleviates the issue by adding extra notes demonstrating which implicit deduction guide we're deducing against. In other words, in addition to the note of `could not match 'T *' against 'int'`, we would also say the implicit deduction guide we're trying to use: `template <class T> S(T *) -> S<T>`, which looks clearer IMO.
>From 23844cd8b8fad07bce0c34f58430322090c5a793 Mon Sep 17 00:00:00 2001
From: Younan Zhang <zyn7109 at gmail.com>
Date: Wed, 19 Jun 2024 23:25:13 +0800
Subject: [PATCH] [Clang] Add diagnostic notes for implcitly generated
deduction guides
---
clang/docs/ReleaseNotes.rst | 3 ++
.../clang/Basic/DiagnosticSemaKinds.td | 1 +
clang/lib/Sema/SemaOverload.cpp | 30 +++++++++++++++++++
clang/test/CXX/drs/cwg26xx.cpp | 3 ++
.../CXX/expr/expr.post/expr.type.conv/p1.cpp | 2 +-
.../over.match.class.deduct/p2.cpp | 2 +-
.../temp.deduct/temp.deduct.call/p3-0x.cpp | 4 +--
clang/test/Modules/template_name_lookup.cpp | 2 ++
clang/test/PCH/cxx-explicit-specifier.cpp | 2 +-
clang/test/Sema/tls_alignment.cpp | 4 ++-
...xx1z-class-template-argument-deduction.cpp | 6 ++--
clang/test/SemaCXX/cxx20-ctad-type-alias.cpp | 17 +++++++++--
clang/test/SemaCXX/cxx2a-explicit-bool.cpp | 2 ++
clang/test/SemaCXX/gh65522.cpp | 3 +-
...deduction-guide-as-template-candidates.cpp | 4 ++-
.../lookup-template-name-extern-CXX.cpp | 6 ++--
.../aggregate-deduction-candidate.cpp | 24 ++++++++-------
clang/test/SemaTemplate/class-template-id.cpp | 2 ++
clang/test/SemaTemplate/ctad.cpp | 6 ++--
clang/test/SemaTemplate/deduction-crash.cpp | 3 +-
clang/test/SemaTemplate/deduction-guide.cpp | 6 ++--
.../nested-implicit-deduction-guides.cpp | 3 ++
clang/test/SemaTemplate/temp_arg.cpp | 4 ++-
23 files changed, 108 insertions(+), 31 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 69aea6c21ad39..423f1e9198948 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -580,6 +580,9 @@ Improvements to Clang's diagnostics
- Clang no longer emits a "declared here" note for a builtin function that has no declaration in source.
Fixes #GH93369.
+- Clang now emits implicit deduction guides corresponding to non-user-defined constructors while at a failure
+ of overload resolution.
+
Improvements to Clang's time-trace
----------------------------------
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index ab223f2b806d5..a65491b0c4399 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2405,6 +2405,7 @@ def err_selected_explicit_constructor : Error<
"chosen constructor is explicit in copy-initialization">;
def note_explicit_ctor_deduction_guide_here : Note<
"explicit %select{constructor|deduction guide}0 declared here">;
+def note_implicit_deduction_guide : Note<"implicit deduction guide declared as '%0'">;
// C++11 auto
def warn_cxx98_compat_auto_type_specifier : Warning<
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index fb4ff72e42eb5..31b908eb3cc3c 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -40,6 +40,7 @@
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/STLForwardCompat.h"
+#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
@@ -12114,6 +12115,35 @@ static void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand,
return;
}
+ // If this is an implicit deduction guide against a non-user-defined
+ // constructor, add a note for it. These deduction guides nor their
+ // corresponding constructors are not explicitly spelled in the source code,
+ // and simply producing a deduction failure note around the heading of the
+ // enclosing RecordDecl is confusing.
+ //
+ // We prefer adding such notes at the end of the last deduction failure
+ // reason because duplicate code snippets appearing in the diagnostic
+ // are likely becoming noisy.
+ auto _ = llvm::make_scope_exit([&] {
+ auto *DG = dyn_cast<CXXDeductionGuideDecl>(Fn);
+ if (!DG || !DG->isImplicit() || DG->getCorrespondingConstructor())
+ return;
+ std::string FunctionProto;
+ llvm::raw_string_ostream OS(FunctionProto);
+ FunctionTemplateDecl *Template = DG->getDescribedFunctionTemplate();
+ // This also could be an instantiation. Find out the primary template.
+ if (!Template) {
+ FunctionDecl *Pattern = DG->getTemplateInstantiationPattern();
+ assert(Pattern && Pattern->getDescribedFunctionTemplate() &&
+ "Cannot find the associated function template of "
+ "CXXDeductionGuideDecl?");
+ Template = Pattern->getDescribedFunctionTemplate();
+ }
+ Template->print(OS);
+ S.Diag(DG->getLocation(), diag::note_implicit_deduction_guide)
+ << FunctionProto;
+ });
+
switch (Cand->FailureKind) {
case ovl_fail_too_many_arguments:
case ovl_fail_too_few_arguments:
diff --git a/clang/test/CXX/drs/cwg26xx.cpp b/clang/test/CXX/drs/cwg26xx.cpp
index 2b17c8101438d..95dfa229530fb 100644
--- a/clang/test/CXX/drs/cwg26xx.cpp
+++ b/clang/test/CXX/drs/cwg26xx.cpp
@@ -194,8 +194,11 @@ static_assert(__is_same(decltype(i), I<char, 4>));
J j = { "ghi" };
// since-cxx20-error at -1 {{no viable constructor or deduction guide}}
// since-cxx20-note@#cwg2681-J {{candidate template ignored: could not match 'J<N>' against 'const char *'}}
+// since-cxx20-note@#cwg2681-J {{implicit deduction guide declared as 'template <size_t N> J(J<N>) -> J<N>'}}
// since-cxx20-note@#cwg2681-J {{candidate template ignored: could not match 'const unsigned char' against 'const char'}}
+// since-cxx20-note@#cwg2681-J {{implicit deduction guide declared as 'template <size_t N> J(const unsigned char (&)[N]) -> J<N>'}}
// since-cxx20-note@#cwg2681-J {{candidate function template not viable: requires 0 arguments, but 1 was provided}}
+// since-cxx20-note@#cwg2681-J {{implicit deduction guide declared as 'template <size_t N> J() -> J<N>'}}
#endif
}
diff --git a/clang/test/CXX/expr/expr.post/expr.type.conv/p1.cpp b/clang/test/CXX/expr/expr.post/expr.type.conv/p1.cpp
index f3608bc378bc7..aa3c022e9b134 100644
--- a/clang/test/CXX/expr/expr.post/expr.type.conv/p1.cpp
+++ b/clang/test/CXX/expr/expr.post/expr.type.conv/p1.cpp
@@ -1,6 +1,6 @@
// RUN: %clang_cc1 -std=c++1z -verify %s
-template<typename T> struct A { // expected-note 2{{candidate}}
+template<typename T> struct A { // expected-note 2{{candidate}} {{implicit deduction guide}}
T t, u;
};
template<typename T> A(T, T) -> A<T>; // expected-note {{deduced conflicting types for parameter 'T'}}
diff --git a/clang/test/CXX/over/over.match/over.match.funcs/over.match.class.deduct/p2.cpp b/clang/test/CXX/over/over.match/over.match.funcs/over.match.class.deduct/p2.cpp
index 49fde292f6a36..4bcf4ee2e3fe7 100644
--- a/clang/test/CXX/over/over.match/over.match.funcs/over.match.class.deduct/p2.cpp
+++ b/clang/test/CXX/over/over.match/over.match.funcs/over.match.class.deduct/p2.cpp
@@ -35,7 +35,7 @@ namespace std {
}
namespace p0702r1 {
- template<typename T> struct X { // expected-note {{candidate}}
+ template<typename T> struct X { // expected-note {{candidate}} expected-note {{implicit deduction guide}}
X(std::initializer_list<T>); // expected-note {{candidate template ignored: could not match 'std::initializer_list<T>' against 'Z'}}
};
diff --git a/clang/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p3-0x.cpp b/clang/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p3-0x.cpp
index 8592626269eed..2e39697a1f07f 100644
--- a/clang/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p3-0x.cpp
+++ b/clang/test/CXX/temp/temp.fct.spec/temp.deduct/temp.deduct.call/p3-0x.cpp
@@ -6,7 +6,7 @@
#if __cplusplus > 201402L
namespace ClassTemplateParamNotForwardingRef {
// This is not a forwarding reference.
- template<typename T> struct A { // expected-note {{candidate}}
+ template<typename T> struct A { // expected-note {{candidate}} expected-note {{implicit deduction guide}}
A(T&&); // expected-note {{expects an rvalue}}
};
int n;
@@ -75,7 +75,7 @@ namespace std_example {
int n3 = g(i); // expected-error{{no matching function for call to 'g'}}
#if __cplusplus > 201402L
- template<class T> struct A { // expected-note {{candidate}}
+ template<class T> struct A { // expected-note {{candidate}} expected-note {{implicit deduction guide}}
template<class U>
A(T &&, U &&, int *); // expected-note {{[with T = int, U = int] not viable: expects an rvalue}}
A(T &&, int *); // expected-note {{requires 2}}
diff --git a/clang/test/Modules/template_name_lookup.cpp b/clang/test/Modules/template_name_lookup.cpp
index 29375e514025f..82b06e83afce3 100644
--- a/clang/test/Modules/template_name_lookup.cpp
+++ b/clang/test/Modules/template_name_lookup.cpp
@@ -7,5 +7,7 @@ import foo;
void use() {
X x; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'X'}}
// expected-note at Inputs/template_name_lookup/foo.cppm:3 {{candidate template ignored: couldn't infer template argument 'T'}}
+ // expected-note at Inputs/template_name_lookup/foo.cppm:3 {{implicit deduction guide declared as 'template <typename T> X(X<T>) -> X<T>'}}
// expected-note at Inputs/template_name_lookup/foo.cppm:3 {{candidate function template not viable: requires 1 argument, but 0 were provided}}
+ // expected-note at Inputs/template_name_lookup/foo.cppm:3 {{implicit deduction guide declared as 'template <typename T> X() -> X<T>'}}
}
diff --git a/clang/test/PCH/cxx-explicit-specifier.cpp b/clang/test/PCH/cxx-explicit-specifier.cpp
index 94ca9f7b080db..68dfc911164c5 100644
--- a/clang/test/PCH/cxx-explicit-specifier.cpp
+++ b/clang/test/PCH/cxx-explicit-specifier.cpp
@@ -79,7 +79,7 @@ struct A {
B<true> b_true;
B<false> b_false;
#else
-//expected-note at -8 {{candidate template ignored}}
+//expected-note at -8 {{candidate template ignored}} expected-note at -8 {{implicit deduction guide declared as 'template <bool b> A(A<b>) -> A<b>'}}
//expected-note at -8 {{explicit constructor declared here}}
//expected-note at -15+ {{candidate constructor}}
//expected-note at -8+ {{explicit conversion function is not a candidate (explicit specifier}}
diff --git a/clang/test/Sema/tls_alignment.cpp b/clang/test/Sema/tls_alignment.cpp
index c5c79aafa9ead..65b6b035e7917 100644
--- a/clang/test/Sema/tls_alignment.cpp
+++ b/clang/test/Sema/tls_alignment.cpp
@@ -22,7 +22,9 @@ struct struct_with_aligned_field {
template <typename>
struct templated_struct {};
// expected-note at -1{{candidate template ignored: couldn't infer template argument ''}}
-// expected-note at -2{{candidate function template not viable: requires 1 argument, but 0 were provided}}
+// expected-note at -2{{implicit deduction guide declared as 'template <typename> templated_struct() -> templated_struct<type-parameter-0-0>'}}
+// expected-note at -3{{candidate function template not viable: requires 1 argument, but 0 were provided}}
+// expected-note at -4{{implicit deduction guide declared as 'template <typename> templated_struct(templated_struct<type-parameter-0-0>) -> templated_struct<type-parameter-0-0>'}}
// A typedef of the aligned struct.
typedef aligned_struct another_aligned_struct;
diff --git a/clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp b/clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
index 90404f115c75f..0a296b32cfb6f 100644
--- a/clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
+++ b/clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
@@ -139,7 +139,8 @@ namespace look_into_current_instantiation {
// templates, and members of the current instantiation
A<float> &r = a;
- template<typename T> struct B { // expected-note {{could not match 'B<T>' against 'int'}}
+ template<typename T> struct B { // expected-note {{could not match 'B<T>' against 'int'}} \
+ expected-note {{implicit deduction guide declared as 'template <typename T> B(B<T>) -> B<T>'}}
struct X {
typedef T type;
};
@@ -564,7 +565,8 @@ namespace PR47175 {
// Ensure we don't crash when CTAD fails.
template <typename T1, typename T2>
-struct Foo { // expected-note{{candidate function template not viable}}
+struct Foo { // expected-note{{candidate function template not viable}} \
+ expected-note{{implicit deduction guide declared as 'template <typename T1, typename T2> Foo(Foo<T1, T2>) -> Foo<T1, T2>'}}
Foo(T1, T2); // expected-note{{candidate function template not viable}}
};
diff --git a/clang/test/SemaCXX/cxx20-ctad-type-alias.cpp b/clang/test/SemaCXX/cxx20-ctad-type-alias.cpp
index b71dfc6ccaf4f..901f64434bbee 100644
--- a/clang/test/SemaCXX/cxx20-ctad-type-alias.cpp
+++ b/clang/test/SemaCXX/cxx20-ctad-type-alias.cpp
@@ -108,8 +108,11 @@ struct Foo {
Foo(T const (&)[N]);
};
+// FIXME: Clarify that __is_deducible constraints are unsatisfied. For example, GCC currently prints the code snippet around constructors
+// FIXME: Prefer non-canonical template arguments in the deduction guide?
template <typename X, int Y>
using Bar = Foo<X, sizeof(X)>; // expected-note {{candidate template ignored: couldn't infer template argument 'X'}} \
+ // expected-note {{implicit deduction guide declared as 'template <typename X> Bar(Foo<type-parameter-0-0, sizeof(type-parameter-0-0)>) -> Foo<type-parameter-0-0, sizeof(type-parameter-0-0)>'}} \
// expected-note {{candidate template ignored: constraints not satisfied [with X = int]}} \
// expected-note {{cannot deduce template arguments for 'Bar' from 'Foo<int, 4UL>'}}
@@ -137,9 +140,12 @@ struct A {};
template<class T> struct Foo { T c; };
template<class X, class Y=A>
using AFoo = Foo<Y>; // expected-note {{candidate template ignored: could not match 'Foo<type-parameter-0-0>' against 'int'}} \
+ // expected-note {{implicit deduction guide declared as 'template <class Y = A> AFoo(Foo<type-parameter-0-0>) -> Foo<type-parameter-0-0>'}} \
// expected-note {{candidate template ignored: constraints not satisfied [with Y = int]}} \
// expected-note {{cannot deduce template arguments for 'AFoo' from 'Foo<int>'}} \
- // expected-note {{candidate function template not viable: requires 0 arguments, but 1 was provided}}
+ // expected-note {{implicit deduction guide declared as 'template <class Y = A> AFoo(type-parameter-0-0) -> Foo<type-parameter-0-0>'}} \
+ // expected-note {{candidate function template not viable: requires 0 arguments, but 1 was provided}} \
+ // expected-note {{implicit deduction guide declared as 'template <class Y = A> AFoo() -> Foo<type-parameter-0-0>'}}
AFoo s = {1}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'AFoo'}}
} // namespace test11
@@ -192,6 +198,7 @@ struct Foo {
template <int K>
using Bar = Foo<double, K>; // expected-note {{constraints not satisfied for class template 'Foo'}}
// expected-note at -1 {{candidate template ignored: could not match}}
+// expected-note at -2 {{implicit deduction guide declared as 'template <int K> Bar(Foo<double, K>) -> Foo<double, K>'}}
double abc[3];
Bar s2 = {abc}; // expected-error {{no viable constructor or deduction guide for deduction }}
} // namespace test14
@@ -204,6 +211,7 @@ template<typename> concept False = false;
template<False W>
using BFoo = AFoo<W>; // expected-note {{candidate template ignored: constraints not satisfied [with V = int]}} \
// expected-note {{cannot deduce template arguments for 'BFoo' from 'Foo<int *>'}} \
+ // expected-note {{implicit deduction guide declared as 'template <class V> BFoo(Foo<type-parameter-0-0 *>) -> Foo<type-parameter-0-0 *>'}} \
// expected-note {{candidate template ignored: could not match 'Foo<type-parameter-0-0 *>' against 'int *'}}
int i = 0;
AFoo a1(&i); // OK, deduce Foo<int *>
@@ -256,7 +264,9 @@ Foo(T) -> Foo<int>;
template <typename U>
using Bar = Foo<U>; // expected-note {{could not match 'Foo<type-parameter-0-0>' against 'int'}} \
// expected-note {{candidate template ignored: constraints not satisfied}} \
- // expected-note {{candidate function template not viable}}
+ // expected-note {{candidate function template not viable}} \
+ // expected-note {{implicit deduction guide declared as 'template <typename U> Bar() -> Foo<type-parameter-0-0>'}} \
+ // expected-note {{implicit deduction guide declared as 'template <typename U> Bar(Foo<type-parameter-0-0>) -> Foo<type-parameter-0-0>'}}
Bar s = {1}; // expected-error {{no viable constructor or deduction guide for deduction of template arguments}}
} // namespace test18
@@ -284,7 +294,8 @@ class Foo {};
// Verify that template template type parameter TTP is referenced/used in the
// template arguments of the RHS.
template <template<typename> typename TTP>
-using Bar = Foo<K<TTP>>; // expected-note {{candidate template ignored: could not match 'Foo<K<template-parameter-0-0>>' against 'int'}}
+using Bar = Foo<K<TTP>>; // expected-note {{candidate template ignored: could not match 'Foo<K<template-parameter-0-0>>' against 'int'}} \
+ // expected-note {{implicit deduction guide declared as 'template <template <typename> typename TTP> Bar(Foo<K<template-parameter-0-0>>) -> Foo<K<template-parameter-0-0>>'}}
template <class T>
class Container {};
diff --git a/clang/test/SemaCXX/cxx2a-explicit-bool.cpp b/clang/test/SemaCXX/cxx2a-explicit-bool.cpp
index 9fdc059493aac..13b5ff1d59b31 100644
--- a/clang/test/SemaCXX/cxx2a-explicit-bool.cpp
+++ b/clang/test/SemaCXX/cxx2a-explicit-bool.cpp
@@ -394,6 +394,7 @@ using type = T;
template<typename T1, typename T2, bool b>
struct A {
// expected-note at -1+ {{candidate function}}
+ // expected-note at -2+ {{implicit deduction guide}}
explicit(false)
A(typename nondeduced<T1>::type, typename nondeduced<T2>::type, typename nondeduced<B<b>>::type) {}
// expected-note at -1+ {{candidate template ignored}}
@@ -678,6 +679,7 @@ namespace deduction_guide2 {
template<typename T1 = int, typename T2 = int>
struct A {
// expected-note at -1+ {{candidate template ignored}}
+ // expected-note at -2+ {{implicit deduction guide}}
explicit(!is_same<T1, T2>::value)
A(T1 = 0, T2 = 0) {}
// expected-note at -1 {{explicit constructor declared here}}
diff --git a/clang/test/SemaCXX/gh65522.cpp b/clang/test/SemaCXX/gh65522.cpp
index 2d6331b0372a3..bfc3a1e12fe76 100644
--- a/clang/test/SemaCXX/gh65522.cpp
+++ b/clang/test/SemaCXX/gh65522.cpp
@@ -3,7 +3,8 @@
class X {};
template<typename T>
-class B3 { // expected-note {{candidate template ignored: could not match 'B3<T>' against 'int'}}
+class B3 { // expected-note {{candidate template ignored: could not match 'B3<T>' against 'int'}} \
+ // expected-note {{implicit deduction guide declared as 'template <typename T> B3(B3<T>) -> B3<T>'}}
template<X x> B3(T); // expected-warning 2{{non-type template parameter of type 'X' is incompatible with C++ standards before C++20}} \
// expected-note {{candidate template ignored: couldn't infer template argument 'x'}}
};
diff --git a/clang/test/SemaCXX/invalid-deduction-guide-as-template-candidates.cpp b/clang/test/SemaCXX/invalid-deduction-guide-as-template-candidates.cpp
index e9b362d67cd23..ad7441ff48477 100644
--- a/clang/test/SemaCXX/invalid-deduction-guide-as-template-candidates.cpp
+++ b/clang/test/SemaCXX/invalid-deduction-guide-as-template-candidates.cpp
@@ -1,6 +1,8 @@
// RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify %s
template <class T> class Foo {}; // expected-note {{candidate template ignored: couldn't infer template argument 'T'}} \
- // expected-note {{candidate function template not viable: requires 1 argument, but 0 were provided}}
+ // expected-note {{implicit deduction guide declared as 'template <class T> Foo(Foo<T>) -> Foo<T>'}} \
+ // expected-note {{candidate function template not viable: requires 1 argument, but 0 were provided}} \
+ // expected-note {{implicit deduction guide declared as 'template <class T> Foo() -> Foo<T>'}}
Foo(); // expected-error {{deduction guide declaration without trailing return type}}
Foo vs; // expected-error {{no viable constructor or deduction guide for deduction of template arguments of 'Foo'}}
diff --git a/clang/test/SemaCXX/lookup-template-name-extern-CXX.cpp b/clang/test/SemaCXX/lookup-template-name-extern-CXX.cpp
index 93e7fb6199354..f851af7ecec26 100644
--- a/clang/test/SemaCXX/lookup-template-name-extern-CXX.cpp
+++ b/clang/test/SemaCXX/lookup-template-name-extern-CXX.cpp
@@ -3,8 +3,10 @@
// RUN: %clang_cc1 -std=c++20 %s -fsyntax-only -verify
extern "C++" {
template <class T>
-class X {}; // expected-note {{candidate template ignored: couldn't infer template argument 'T'}}
- // expected-note at -1 {{candidate function template not viable: requires 1 argument, but 0 were provided}}
+class X {}; // expected-note {{candidate template ignored: couldn't infer template argument 'T'}} \
+ // expected-note {{implicit deduction guide declared as 'template <class T> X(X<T>) -> X<T>'}} \
+ // expected-note {{candidate function template not viable: requires 1 argument, but 0 were provided}} \
+ // expected-note {{implicit deduction guide declared as 'template <class T> X() -> X<T>'}}
}
void foo() {
diff --git a/clang/test/SemaTemplate/aggregate-deduction-candidate.cpp b/clang/test/SemaTemplate/aggregate-deduction-candidate.cpp
index 5a50332d73307..49afb6b860620 100644
--- a/clang/test/SemaTemplate/aggregate-deduction-candidate.cpp
+++ b/clang/test/SemaTemplate/aggregate-deduction-candidate.cpp
@@ -2,7 +2,7 @@
// RUN: %clang_cc1 -std=c++20 -verify=expected,cxx20 -ast-dump -ast-dump-decl-types -ast-dump-filter "deduction guide" %s | FileCheck %s --strict-whitespace
namespace Basic {
- template<class T> struct A { // cxx17-note 6 {{candidate}}
+ template<class T> struct A { // cxx17-note 6 {{candidate}} cxx17-note 6 {{implicit deduction guide}}
T x;
T y;
};
@@ -36,12 +36,14 @@ namespace Basic {
T y;
};
- template <typename T> struct C { // cxx20-note 10 {{candidate}} cxx17-note 12 {{candidate}}
+ template <typename T> struct C { // cxx20-note 10 {{candidate}} cxx17-note 12 {{candidate}} \
+ cxx20-note 10 {{implicit deduction guide}} cxx17-note 12 {{implicit deduction guide}}
S<T> s;
T t;
};
- template <typename T> struct D { // cxx20-note 6 {{candidate}} cxx17-note 8 {{candidate}}
+ template <typename T> struct D { // cxx20-note 6 {{candidate}} cxx17-note 8 {{candidate}} \
+ cxx20-note 6 {{implicit deduction guide}} cxx17-note 8 {{implicit deduction guide}}
S<int> s;
T t;
};
@@ -99,7 +101,7 @@ namespace Basic {
// CHECK: |-ClassTemplateSpecialization {{.*}} 'S'
// CHECK: `-BuiltinType {{.*}} 'int'
- template <typename T> struct E { // cxx17-note 4 {{candidate}}
+ template <typename T> struct E { // cxx17-note 4 {{candidate}} cxx17-note 4 {{implicit deduction guide}}
T t;
decltype(t) t2;
};
@@ -133,7 +135,7 @@ namespace Basic {
};
template <typename T>
- struct F { // cxx17-note 2 {{candidate}}
+ struct F { // cxx17-note 2 {{candidate}} cxx17-note 2 {{implicit deduction guide}}
typename I<T>::type i;
T t;
};
@@ -161,7 +163,8 @@ namespace Basic {
namespace Array {
typedef unsigned long size_t;
- template <typename T, size_t N> struct A { // cxx20-note 2 {{candidate}} cxx17-note 14 {{candidate}}
+ template <typename T, size_t N> struct A { // cxx20-note 2 {{candidate}} cxx17-note 14 {{candidate}} \
+ cxx20-note 2 {{implicit deduction guide}} cxx17-note 14 {{implicit deduction guide}}
T array[N];
};
@@ -217,7 +220,7 @@ namespace Array {
}
namespace BraceElision {
- template <typename T> struct A { // cxx17-note 4 {{candidate}}
+ template <typename T> struct A { // cxx17-note 4 {{candidate}} cxx17-note 4 {{implicit deduction guide}}
T array[2];
};
@@ -247,7 +250,7 @@ namespace BraceElision {
}
namespace TrailingPack {
- template<typename... T> struct A : T... { // cxx17-note 4 {{candidate}}
+ template<typename... T> struct A : T... { // cxx17-note 4 {{candidate}} cxx17-note 4 {{implicit deduction guide}}
};
A a1 = { // cxx17-error {{no viable}}
@@ -286,7 +289,7 @@ namespace TrailingPack {
}
namespace NonTrailingPack {
- template<typename... T> struct A : T... { // expected-note 4 {{candidate}}
+ template<typename... T> struct A : T... { // expected-note 4 {{candidate}} expected-note 4 {{implicit deduction guide}}
int a;
};
@@ -303,7 +306,8 @@ namespace NonTrailingPack {
namespace DeduceArity {
template <typename... T> struct Types {};
- template <typename... T> struct F : Types<T...>, T... {}; // cxx20-note 12 {{candidate}} cxx17-note 16 {{candidate}}
+ template <typename... T> struct F : Types<T...>, T... {}; // cxx20-note 12 {{candidate}} cxx17-note 16 {{candidate}} \
+ cxx20-note 12 {{implicit deduction guide}} cxx17-note 16 {{implicit deduction guide}}
struct X {};
struct Y {};
diff --git a/clang/test/SemaTemplate/class-template-id.cpp b/clang/test/SemaTemplate/class-template-id.cpp
index eade4f6290424..96696f62b78a2 100644
--- a/clang/test/SemaTemplate/class-template-id.cpp
+++ b/clang/test/SemaTemplate/class-template-id.cpp
@@ -45,6 +45,8 @@ typedef N::C<float> c2;
// PR5655
template<typename T> struct Foo { }; // precxx17-note {{template is declared here}} \
cxx17-note {{candidate template ignored: couldn't infer template argument 'T'}} \
+ cxx17-note {{implicit deduction guide declared as 'template <typename T> Foo() -> Foo<T>'}} \
+ cxx17-note {{implicit deduction guide declared as 'template <typename T> Foo(Foo<T>) -> Foo<T>'}} \
cxx17-note {{candidate function template not viable: requires 1 argument, but 0 were provided}}
void f(void) { Foo bar; } // precxx17-error {{use of class template 'Foo' requires template arguments}} \
diff --git a/clang/test/SemaTemplate/ctad.cpp b/clang/test/SemaTemplate/ctad.cpp
index e981ea8d5ecfb..c5e467a8d7724 100644
--- a/clang/test/SemaTemplate/ctad.cpp
+++ b/clang/test/SemaTemplate/ctad.cpp
@@ -20,7 +20,8 @@ namespace Access {
protected:
struct type {};
};
- template<typename T> struct D : B { // expected-note {{not viable}}
+ template<typename T> struct D : B { // expected-note {{not viable}} \
+ expected-note {{implicit deduction guide declared as 'template <typename T> D(D<T>) -> D<T>'}}
D(T, typename T::type); // expected-note {{private member}}
};
D b = {B(), {}};
@@ -64,7 +65,8 @@ class C : A<int> {
using A::A;
};
template <typename>
-class D : C { // expected-note {{candidate function template not viable: requires 1 argument}}
+class D : C { // expected-note {{candidate function template not viable: requires 1 argument}} \
+ expected-note {{implicit deduction guide declared as 'template <typename> D(D<type-parameter-0-0>) -> D<type-parameter-0-0>'}}
using C::C;
};
D abc; // expected-error {{no viable constructor or deduction guide}}
diff --git a/clang/test/SemaTemplate/deduction-crash.cpp b/clang/test/SemaTemplate/deduction-crash.cpp
index 86ec9f7980a7d..e3f97c594aa90 100644
--- a/clang/test/SemaTemplate/deduction-crash.cpp
+++ b/clang/test/SemaTemplate/deduction-crash.cpp
@@ -166,8 +166,9 @@ namespace PR51872_part1 {
template<int> class T1 { template <struct U1> T1(); };
// expected-error at -1 {{non-type template parameter has incomplete type 'struct U1'}}
// expected-note at -2 {{forward declaration of 'PR51872_part1::U1'}}
+ // expected-note at -3 {{implicit deduction guide declared as 'template <int> T1(T1<>) -> T1<>'}}
T1 t1 = 0;
// expected-error at -1 {{no viable constructor or deduction guide for deduction of template arguments of 'T1'}}
- // expected-note at -6 {{candidate template ignored: could not match 'T1<>' against 'int'}}
+ // expected-note at -7 {{candidate template ignored: could not match 'T1<>' against 'int'}}
}
diff --git a/clang/test/SemaTemplate/deduction-guide.cpp b/clang/test/SemaTemplate/deduction-guide.cpp
index 163b36519950f..54420be9ee969 100644
--- a/clang/test/SemaTemplate/deduction-guide.cpp
+++ b/clang/test/SemaTemplate/deduction-guide.cpp
@@ -123,7 +123,8 @@ using CT = C<int>;
// CHECK: | `-TemplateArgument template
// CHECK: `-TemplateTypeParmType {{.*}} 'type-parameter-0-2' dependent depth 0 index 2
-template<typename ...T> struct D { // expected-note {{candidate}}
+template<typename ...T> struct D { // expected-note {{candidate}} \
+ expected-note {{implicit deduction guide declared as 'template <typename ...T> D(D<T...>) -> D<T...>'}}
template<typename... U> using B = int(int (*...p)(T, U));
template<typename U1, typename U2> D(B<U1, U2>*); // expected-note {{candidate}}
};
@@ -166,7 +167,8 @@ using DT = D<int, int>;
// CHECK-NOT: Subst
// CHECK: `-TemplateTypeParmType
-template<int ...N> struct E { // expected-note {{candidate}}
+template<int ...N> struct E { // expected-note {{candidate}} \
+ expected-note {{implicit deduction guide declared as 'template <int ...N> E(E<N...>) -> E<N...>'}}
template<int ...M> using B = Z<X<N, M>...>;
template<int M1, int M2> E(B<M1, M2>); // expected-note {{candidate}}
};
diff --git a/clang/test/SemaTemplate/nested-implicit-deduction-guides.cpp b/clang/test/SemaTemplate/nested-implicit-deduction-guides.cpp
index a4ae046ac5274..af3e3358f6138 100644
--- a/clang/test/SemaTemplate/nested-implicit-deduction-guides.cpp
+++ b/clang/test/SemaTemplate/nested-implicit-deduction-guides.cpp
@@ -82,8 +82,11 @@ using NIL = nested_init_list<int>::B<int>;
// expected-error at +1 {{no viable constructor or deduction guide for deduction of template arguments of 'nested_init_list<int>::concept_fail'}}
nested_init_list<int>::concept_fail nil_invalid{1, ""};
// expected-note@#INIT_LIST_INNER_INVALID {{candidate template ignored: substitution failure [with F = const char *]: constraints not satisfied for class template 'concept_fail' [with F = const char *]}}
+// expected-note@#INIT_LIST_INNER_INVALID {{implicit deduction guide declared as 'template <False F> concept_fail(int, F) -> concept_fail<F>'}}
// expected-note@#INIT_LIST_INNER_INVALID {{candidate function template not viable: requires 1 argument, but 2 were provided}}
+// expected-note@#INIT_LIST_INNER_INVALID {{implicit deduction guide declared as 'template <False F> concept_fail(concept_fail<F>) -> concept_fail<F>'}}
// expected-note@#INIT_LIST_INNER_INVALID {{candidate function template not viable: requires 0 arguments, but 2 were provided}}
+// expected-note@#INIT_LIST_INNER_INVALID {{implicit deduction guide declared as 'template <False F> concept_fail() -> concept_fail<F>'}}
namespace GH88142 {
diff --git a/clang/test/SemaTemplate/temp_arg.cpp b/clang/test/SemaTemplate/temp_arg.cpp
index 2db4a51d6cccb..538056a4e44c7 100644
--- a/clang/test/SemaTemplate/temp_arg.cpp
+++ b/clang/test/SemaTemplate/temp_arg.cpp
@@ -6,7 +6,9 @@ template<typename T,
class A; // precxx17-note 3 {{template is declared here}} \
cxx17-note 2 {{template is declared here}} \
cxx17-note {{candidate template ignored: couldn't infer template argument 'T'}} \
- cxx17-note {{candidate function template not viable: requires 1 argument, but 0 were provided}}
+ cxx17-note {{implicit deduction guide declared as 'template <typename T, int I, template <typename> class TT> A(A<T, I, TT>) -> A<T, I, TT>'}} \
+ cxx17-note {{candidate function template not viable: requires 1 argument, but 0 were provided}} \
+ cxx17-note {{implicit deduction guide declared as 'template <typename T, int I, template <typename> class TT> A() -> A<T, I, TT>'}} \
template<typename> class X;
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