xref: /llvm-project/clang/test/SemaTemplate/deduction-guide.cpp (revision 8c2574832ed2064996389e4259eaf0bea0fa7951)
1 // RUN: %clang_cc1 -std=c++2a -verify -ast-dump -ast-dump-decl-types -ast-dump-filter "deduction guide" %s | FileCheck %s --strict-whitespace
2 
3 template<auto ...> struct X {};
4 template<template<typename X, X> typename> struct Y {};
5 template<typename ...> struct Z {};
6 
7 template<typename T, typename ...Ts> struct A {
8   template<Ts ...Ns, T *...Ps> A(X<Ps...>, Ts (*...qs)[Ns]);
9 };
10 int arr1[3], arr2[3];
11 short arr3[4];
12 A a(X<&arr1, &arr2>{}, &arr1, &arr2, &arr3);
13 using AT = decltype(a);
14 using AT = A<int[3], int, int, short>;
15 
16 // CHECK-LABEL: Dumping <deduction guide for A>:
17 // CHECK: FunctionTemplateDecl
18 // CHECK: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 0 T
19 // CHECK: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 1 ... Ts
20 // CHECK: |-NonTypeTemplateParmDecl {{.*}} 'Ts...' depth 0 index 2 ... Ns
21 // CHECK: |-NonTypeTemplateParmDecl {{.*}} 'T *' depth 0 index 3 ... Ps
22 // CHECK: |-CXXDeductionGuideDecl
23 // CHECK: | |-ParmVarDecl {{.*}} 'X<Ps...>'
24 // CHECK: | `-ParmVarDecl {{.*}} 'Ts (*)[Ns]...' pack
25 // CHECK: `-CXXDeductionGuideDecl
26 // CHECK:   |-TemplateArgument type 'int[3]'
27 // CHECK:   |-TemplateArgument pack
28 // CHECK:   | |-TemplateArgument type 'int'
29 // CHECK:   | |-TemplateArgument type 'int'
30 // CHECK:   | `-TemplateArgument type 'short'
31 // CHECK:   |-TemplateArgument pack
32 // CHECK:   | |-TemplateArgument integral '3'
33 // CHECK:   | |-TemplateArgument integral '3'
34 // CHECK:   | `-TemplateArgument integral '(short)4'
35 // CHECK:   |-TemplateArgument pack
36 // CHECK:   | |-TemplateArgument decl
37 // CHECK:   | | `-Var {{.*}} 'arr1' 'int[3]'
38 // CHECK:   | `-TemplateArgument decl
39 // CHECK:   |   `-Var {{.*}} 'arr2' 'int[3]'
40 // CHECK:   |-ParmVarDecl {{.*}} 'X<&arr1, &arr2>'
41 // CHECK:   |-ParmVarDecl {{.*}} 'int (*)[3]'
42 // CHECK:   |-ParmVarDecl {{.*}} 'int (*)[3]'
43 // CHECK:   `-ParmVarDecl {{.*}} 'short (*)[4]'
44 // CHECK: FunctionProtoType {{.*}} 'auto (X<Ps...>, Ts (*)[Ns]...) -> A<T, Ts...>' dependent trailing_return
45 // CHECK: |-InjectedClassNameType {{.*}} 'A<T, Ts...>' dependent
46 // CHECK: |-ElaboratedType {{.*}} 'X<Ps...>' sugar dependent
47 // CHECK: | `-TemplateSpecializationType {{.*}} 'X<Ps...>' dependent
48 // CHECK: |   `-TemplateArgument expr
49 // CHECK: |     `-PackExpansionExpr {{.*}} 'T *'
50 // CHECK: |       `-DeclRefExpr {{.*}} 'T *' NonTypeTemplateParm {{.*}} 'Ps' 'T *'
51 // CHECK: `-PackExpansionType {{.*}} 'Ts (*)[Ns]...' dependent
52 // CHECK:   `-PointerType {{.*}} 'Ts (*)[Ns]' dependent contains_unexpanded_pack
53 // CHECK:     `-ParenType {{.*}} 'Ts[Ns]' sugar dependent contains_unexpanded_pack
54 // CHECK:       `-DependentSizedArrayType {{.*}} 'Ts[Ns]' dependent contains_unexpanded_pack
55 // CHECK:         |-TemplateTypeParmType {{.*}} 'Ts' dependent contains_unexpanded_pack depth 0 index 1 pack
56 // CHECK:         | `-TemplateTypeParm {{.*}} 'Ts'
57 // CHECK:         `-DeclRefExpr {{.*}} 'Ts' NonTypeTemplateParm {{.*}} 'Ns' 'Ts...'
58 
59 template<typename T, T V> struct B {
60   template<typename U, U W> B(X<W, V>);
61 };
62 B b(X<nullptr, 'x'>{});
63 using BT = decltype(b);
64 using BT = B<char, 'x'>;
65 
66 // CHECK-LABEL: Dumping <deduction guide for B>:
67 // CHECK: FunctionTemplateDecl
68 // CHECK: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 0 T
69 // CHECK: |-NonTypeTemplateParmDecl {{.*}} 'T' depth 0 index 1 V
70 // CHECK: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 2 U
71 // CHECK: |-NonTypeTemplateParmDecl {{.*}} 'U' depth 0 index 3 W
72 // CHECK: |-CXXDeductionGuideDecl {{.*}} 'auto (X<W, V>) -> B<T, V>'
73 // CHECK: | `-ParmVarDecl {{.*}} 'X<W, V>'
74 // CHECK: `-CXXDeductionGuideDecl {{.*}} 'auto (X<nullptr, 'x'>) -> B<char, 'x'>'
75 // CHECK:   |-TemplateArgument type 'char'
76 // CHECK:   |-TemplateArgument integral ''x''
77 // CHECK:   |-TemplateArgument type 'std::nullptr_t'
78 // CHECK:   |-TemplateArgument nullptr
79 // CHECK:   `-ParmVarDecl {{.*}} 'X<nullptr, 'x'>'
80 // CHECK: FunctionProtoType {{.*}} 'auto (X<W, V>) -> B<T, V>' dependent trailing_return
81 // CHECK: |-InjectedClassNameType {{.*}} 'B<T, V>' dependent
82 // CHECK: `-TemplateSpecializationType {{.*}} 'X<W, V>' dependent
83 // CHECK:   |-TemplateArgument expr
84 // CHECK:   | `-DeclRefExpr {{.*}} 'U' NonTypeTemplateParm {{.*}} 'W' 'U'
85 // CHECK:   `-TemplateArgument expr
86 // CHECK:     `-DeclRefExpr {{.*}} 'T' NonTypeTemplateParm {{.*}} 'V' 'T'
87 
88 template<typename A> struct C {
89   template<template<typename X, X> typename T, typename U, U V = 0> C(A, Y<T>, U);
90 };
91 C c(1, Y<B>{}, 2);
92 using CT = decltype(c);
93 using CT = C<int>;
94 
95 // CHECK-LABEL: Dumping <deduction guide for C>:
96 // CHECK: FunctionTemplateDecl
97 // CHECK: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 0 A
98 // CHECK: |-TemplateTemplateParmDecl {{.*}} depth 0 index 1 T
99 // CHECK: | |-TemplateTypeParmDecl {{.*}} typename depth 1 index 0 X
100 // CHECK: | `-NonTypeTemplateParmDecl {{.*}} 'X' depth 1 index 1
101 // CHECK: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 2 U
102 // CHECK: |-NonTypeTemplateParmDecl {{.*}} 'U' depth 0 index 3 V
103 // CHECK: | `-TemplateArgument {{.*}} expr
104 // CHECK: |   `-IntegerLiteral {{.*}} 'int' 0
105 // CHECK: |-CXXDeductionGuideDecl {{.*}} 'auto (A, Y<T>, U) -> C<A>'
106 // CHECK: | |-ParmVarDecl {{.*}} 'A'
107 // CHECK: | |-ParmVarDecl {{.*}} 'Y<T>'
108 // CHECK: | `-ParmVarDecl {{.*}} 'U'
109 // CHECK: `-CXXDeductionGuideDecl {{.*}} 'auto (int, Y<B>, int) -> C<int>'
110 // CHECK:  |-TemplateArgument type 'int'
111 // CHECK:  |-TemplateArgument template 'B'
112 // CHECK:  |-TemplateArgument type 'int'
113 // CHECK:  |-TemplateArgument integral '0'
114 // CHECK:  |-ParmVarDecl {{.*}} 'int'
115 // CHECK:  |-ParmVarDecl {{.*}} 'Y<B>'
116 // CHECK:  `-ParmVarDecl {{.*}} 'int'
117 // CHECK: FunctionProtoType {{.*}} 'auto (A, Y<T>, U) -> C<A>' dependent trailing_return cdecl
118 // CHECK: |-InjectedClassNameType {{.*}} 'C<A>' dependent
119 // CHECK: |-TemplateTypeParmType {{.*}} 'A' dependent depth 0 index 0
120 // CHECK: | `-TemplateTypeParm {{.*}} 'A'
121 // CHECK: |-ElaboratedType {{.*}} 'Y<T>' sugar dependent
122 // CHECK: | `-TemplateSpecializationType {{.*}} 'Y<T>' dependent
123 // CHECK: |   `-TemplateArgument template
124 // CHECK: `-TemplateTypeParmType {{.*}} 'U' dependent depth 0 index 2
125 
126 template<typename ...T> struct D { // expected-note {{candidate}} \
127                                    // expected-note {{implicit deduction guide declared as 'template <typename ...T> D(D<T...>) -> D<T...>'}}
128   template<typename... U> using B = int(int (*...p)(T, U));
129   template<typename U1, typename U2> D(B<U1, U2>*); // expected-note {{candidate}} \
130                                                     // expected-note {{implicit deduction guide declared as 'template <typename ...T, typename U1, typename U2> D(B<U1, U2> *) -> D<T...>'}}
131 };
132 int f(int(int, int), int(int, int));
133 // FIXME: We can't deduce this because we can't deduce through a
134 // SubstTemplateTypeParmPackType.
135 D d = f; // expected-error {{no viable}}
136 using DT = decltype(d);
137 using DT = D<int, int>;
138 
139 // CHECK-LABEL: Dumping <deduction guide for D>:
140 // CHECK: FunctionTemplateDecl
141 // CHECK: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 0 ... T
142 // CHECK: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 1 U1
143 // CHECK: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 2 U2
144 // CHECK: `-CXXDeductionGuideDecl {{.*}} 'auto (B<U1, U2> *) -> D<T...>'
145 // CHECK:   `-ParmVarDecl {{.*}} 'B<U1, U2> *'
146 // CHECK: FunctionProtoType {{.*}} 'auto (B<U1, U2> *) -> D<T...>' dependent trailing_return
147 // CHECK: |-InjectedClassNameType {{.*}} 'D<T...>' dependent
148 // CHECK: `-PointerType {{.*}} 'B<U1, U2> *' dependent
149 // CHECK:   `-TemplateSpecializationType {{.*}} 'B<U1, U2>' sugar dependent alias
150 // CHECK:     |-TemplateArgument type 'U1'
151 // CHECK:     |-TemplateArgument type 'U2'
152 // CHECK:     `-FunctionProtoType {{.*}} 'int (int (*)(T, U)...)' dependent cdecl
153 // CHECK:       |-BuiltinType {{.*}} 'int'
154 // CHECK:       `-PackExpansionType {{.*}} 'int (*)(T, U)...' dependent expansions 2
155 // CHECK:         `-PointerType {{.*}} 'int (*)(T, U)' dependent contains_unexpanded_pack
156 // CHECK:           `-ParenType {{.*}} 'int (T, U)' sugar dependent contains_unexpanded_pack
157 // CHECK:             `-FunctionProtoType {{.*}} 'int (T, U)' dependent contains_unexpanded_pack cdecl
158 // CHECK:               |-BuiltinType {{.*}} 'int'
159 // CHECK:               |-TemplateTypeParmType {{.*}} 'T' dependent contains_unexpanded_pack depth 0 index 0 pack
160 // CHECK:               | `-TemplateTypeParm {{.*}} 'T'
161 // CHECK:               `-SubstTemplateTypeParmPackType {{.*}} 'U' dependent contains_unexpanded_pack typename depth 1 index 0 ... U
162 // CHECK:                 |-TypeAliasTemplate {{.*}} 'B'
163 // CHECK:                 `-TemplateArgument pack
164 // CHECK:                   |-TemplateArgument type 'U1':'type-parameter-0-1'
165 // CHECK-NOT: Subst
166 // CHECK:                   | `-TemplateTypeParmType
167 // CHECK:                   `-TemplateArgument type 'U2':'type-parameter-0-2'
168 // CHECK-NOT: Subst
169 // CHECK:                     `-TemplateTypeParmType
170 
171 template<int ...N> struct E { // expected-note {{candidate}} \
172                                  expected-note {{implicit deduction guide declared as 'template <int ...N> E(E<N...>) -> E<N...>'}}
173   template<int ...M> using B = Z<X<N, M>...>;
174   template<int M1, int M2> E(B<M1, M2>); // expected-note {{candidate}} \
175                                          // expected-note {{implicit deduction guide declared as 'template <int ...N, int M1, int M2> E(B<M1, M2>) -> E<N...>'}}}}
176 };
177 // FIXME: We can't deduce this because we can't deduce through a
178 // SubstNonTypeTemplateParmPackExpr.
179 E e = Z<X<1, 2>, X<3, 4>>(); // expected-error {{no viable}}
180 using ET = decltype(e);
181 using ET = E<1, 3>;
182 
183 // CHECK-LABEL: Dumping <deduction guide for E>:
184 // CHECK: FunctionTemplateDecl
185 // CHECK: |-NonTypeTemplateParmDecl [[N:0x[0-9a-f]*]] {{.*}} 'int' depth 0 index 0 ... N
186 // CHECK: |-NonTypeTemplateParmDecl [[M1:0x[0-9a-f]*]] {{.*}} 'int' depth 0 index 1 M1
187 // CHECK: |-NonTypeTemplateParmDecl [[M2:0x[0-9a-f]*]] {{.*}} 'int' depth 0 index 2 M2
188 // CHECK: `-CXXDeductionGuideDecl {{.*}} 'auto (B<M1, M2>) -> E<N...>'
189 // CHECK:   `-ParmVarDecl {{.*}} 'B<M1, M2>':'Z<X<N, M>...>'
190 // CHECK: FunctionProtoType {{.*}} 'auto (B<M1, M2>) -> E<N...>' dependent trailing_return
191 // CHECK: |-InjectedClassNameType {{.*}} 'E<N...>' dependent
192 // CHECK: `-TemplateSpecializationType {{.*}} 'B<M1, M2>' sugar dependent alias
193 // CHECK:   |-TemplateArgument expr
194 // CHECK:   | `-DeclRefExpr {{.*}} 'int' NonTypeTemplateParm {{.*}} 'M1' 'int'
195 // CHECK:   |-TemplateArgument expr
196 // CHECK:   | `-DeclRefExpr {{.*}} 'int' NonTypeTemplateParm {{.*}} 'M2' 'int'
197 // CHECK:   `-TemplateSpecializationType {{.*}} 'Z<X<N, M>...>' dependent
198 // CHECK:     `-TemplateArgument type 'X<N, M>...'
199 // CHECK:       `-PackExpansionType {{.*}} 'X<N, M>...' dependent expansions 2
200 // CHECK:         `-TemplateSpecializationType {{.*}} 'X<N, M>' dependent contains_unexpanded_pack
201 // CHECK:           |-TemplateArgument expr
202 // CHECK-NOT: Subst
203 // CHECK:           | `-DeclRefExpr {{.*}} 'int' NonTypeTemplateParm [[N]] 'N' 'int'
204 // CHECK:           `-TemplateArgument expr
205 // CHECK:             `-SubstNonTypeTemplateParmPackExpr {{.*}} 'int'
206 // CHECK:               |-NonTypeTemplateParmDecl {{.*}} referenced 'int' depth 1 index 0 ... M
207 // CHECK:               `-TemplateArgument pack
208 // CHECK:                 |-TemplateArgument expr
209 // CHECK-NOT: Subst
210 // CHECK:                 | `-DeclRefExpr {{.*}} 'int' NonTypeTemplateParm [[M1]] 'M1' 'int'
211 // CHECK:                 `-TemplateArgument expr
212 // CHECK-NOT: Subst
213 // CHECK:                   `-DeclRefExpr {{.*}} 'int' NonTypeTemplateParm [[M2]] 'M2' 'int'
214 
215 template <char = 'x'> struct F;
216 
217 template <char> struct F {
218   template <typename U>
219   requires(false) F(U);
220   template <typename U>
221   requires(true) F(U);
222 };
223 
224 F s(0);
225 
226 // CHECK-LABEL: Dumping <deduction guide for F>:
227 // CHECK: FunctionTemplateDecl
228 // CHECK: |-NonTypeTemplateParmDecl {{.*}} 'char' depth 0 index 0
229 // CHECK:   `-TemplateArgument {{.*}} expr
230 // CHECK: |   |-inherited from NonTypeTemplateParm {{.*}} depth 0 index 0 'char'
231 // CHECK: |   `-CharacterLiteral {{.*}} 'char' 120
232 // CHECK: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 1 U
233 // CHECK: |-ParenExpr {{.*}} 'bool'
234 // CHECK: | `-CXXBoolLiteralExpr {{.*}} 'bool' false
235 // CHECK: |-CXXDeductionGuideDecl {{.*}} implicit <deduction guide for F> 'auto (U) -> F<value-parameter-0-0>'
236 // CHECK: | `-ParmVarDecl {{.*}} 'U'
237 // CHECK: `-CXXDeductionGuideDecl {{.*}} implicit <deduction guide for F> 'auto (int) -> F<>'
238 // CHECK:   |-TemplateArgument integral ''x''
239 // CHECK:   |-TemplateArgument type 'int'
240 // CHECK:   | `-BuiltinType {{.*}} 'int'
241 // CHECK:   `-ParmVarDecl {{.*}} 'int'
242 // CHECK: FunctionProtoType {{.*}} 'auto (U) -> F<value-parameter-0-0>' dependent trailing_return cdecl
243 // CHECK: |-InjectedClassNameType {{.*}} 'F<value-parameter-0-0>' dependent
244 // CHECK: | `-CXXRecord {{.*}} 'F'
245 // CHECK: `-TemplateTypeParmType {{.*}} 'U' dependent depth 0 index 1
246 
247 template<typename T>
248 struct G { T t; };
249 
250 G g = {1};
251 // CHECK-LABEL: Dumping <deduction guide for G>:
252 // CHECK: FunctionTemplateDecl
253 // CHECK: |-CXXDeductionGuideDecl {{.*}} implicit <deduction guide for G> 'auto (T) -> G<T>' aggregate
254 // CHECK: `-CXXDeductionGuideDecl {{.*}} implicit used <deduction guide for G> 'auto (int) -> G<int>' implicit_instantiation aggregate
255 
256 template<typename X>
257 using AG = G<X>;
258 AG ag = {1};
259 // Verify that the aggregate deduction guide for alias templates is built.
260 // CHECK-LABEL: Dumping <deduction guide for AG>
261 // CHECK: FunctionTemplateDecl
262 // CHECK: |-CXXDeductionGuideDecl {{.*}} 'auto (X) -> G<X>'
263 // CHECK: `-CXXDeductionGuideDecl {{.*}} 'auto (int) -> G<int>' implicit_instantiation
264 // CHECK:   |-TemplateArgument type 'int'
265 // CHECK:   | `-BuiltinType {{.*}} 'int'
266 // CHECK:   `-ParmVarDecl {{.*}} 'int'
267 
268 template <typename X = int>
269 using BG = G<int>;
270 BG bg(1.0);
271 // CHECK-LABEL: Dumping <deduction guide for BG>
272 // CHECK: FunctionTemplateDecl {{.*}} implicit <deduction guide for BG>
273 // CHECK: |-CXXDeductionGuideDecl {{.*}} 'auto (int) -> G<int>' aggregate
274 
275 template <typename D>
276 requires (sizeof(D) == 4)
277 struct Foo {
278   Foo(D);
279 };
280 
281 template <typename U>
282 using AFoo = Foo<G<U>>;
283 // Verify that the require-clause from the Foo deduction guide is transformed.
284 // The D occurrence should be rewritten to G<U>.
285 //
286 // CHECK-LABEL: Dumping <deduction guide for AFoo>
287 // CHECK: FunctionTemplateDecl {{.*}} implicit <deduction guide for AFoo>
288 // CHECK-NEXT: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 0 U
289 // CHECK-NEXT: |-BinaryOperator {{.*}} '&&'
290 // CHECK-NEXT: | |-ParenExpr {{.*}} 'bool'
291 // CHECK-NEXT: | | `-BinaryOperator {{.*}} 'bool' '=='
292 // CHECK-NEXT: | |   |-UnaryExprOrTypeTraitExpr {{.*}} 'G<U>'
293 // CHECK-NEXT: | |   `-ImplicitCastExpr {{.*}}
294 // CHECK-NEXT: | |     `-IntegerLiteral {{.*}}
295 // CHECK-NEXT: | `-TypeTraitExpr {{.*}} 'bool' __is_deducible
296 // CHECK-NEXT: |   |-DeducedTemplateSpecializationType {{.*}} 'AFoo' dependent
297 // CHECK-NEXT: |   | `-name: 'AFoo'
298 // CHECK-NEXT: |   |   `-TypeAliasTemplateDecl {{.+}} AFoo
299 // CHECK-NEXT: |   `-TemplateSpecializationType {{.*}} 'Foo<G<U>>' dependent
300 // CHECK:      |-CXXDeductionGuideDecl {{.*}} implicit <deduction guide for AFoo> 'auto (G<U>) -> Foo<G<U>>'
301 // CHECK-NEXT: | `-ParmVarDecl {{.*}} 'G<U>'
302 // CHECK-NEXT: `-CXXDeductionGuideDecl {{.*}} implicit used <deduction guide for AFoo> 'auto (G<int>) -> Foo<G<int>>' implicit_instantiation
303 // CHECK-NEXT:   |-TemplateArgument type 'int'
304 // CHECK-NEXT:   | `-BuiltinType {{.*}} 'int'
305 // CHECK-NEXT:   `-ParmVarDecl {{.*}} 'G<int>'
306 
307 AFoo aa(G<int>{});
308 
309 namespace TTP {
310   template<typename> struct A {};
311 
312   template<class T> struct B {
313     template<template <class> typename TT> B(TT<T>);
314   };
315 
316   B b(A<int>{});
317 } // namespace TTP
318 
319 // CHECK-LABEL: Dumping TTP::<deduction guide for B>:
320 // CHECK-NEXT:  FunctionTemplateDecl 0x{{.+}} <{{.+}}:[[# @LINE - 7]]:5, col:51>
321 // CHECK-NEXT:  |-TemplateTypeParmDecl {{.+}} class depth 0 index 0 T{{$}}
322 // CHECK-NEXT:  |-TemplateTemplateParmDecl {{.+}} depth 0 index 1 TT{{$}}
323 // CHECK-NEXT:  | `-TemplateTypeParmDecl {{.+}} class depth 1 index 0{{$}}
324 // CHECK-NEXT:  |-CXXDeductionGuideDecl {{.+}} 'auto (TT<T>) -> B<T>'{{$}}
325 // CHECK-NEXT:  | `-ParmVarDecl {{.+}} 'TT<T>'{{$}}
326 // CHECK-NEXT:  `-CXXDeductionGuideDecl {{.+}} 'auto (A<int>) -> TTP::B<int>'
327 // CHECK-NEXT:    |-TemplateArgument type 'int'
328 // CHECK-NEXT:    | `-BuiltinType {{.+}} 'int'{{$}}
329 // CHECK-NEXT:    |-TemplateArgument template 'TTP::A'{{$}}
330 // CHECK-NEXT:    | `-ClassTemplateDecl {{.+}} A{{$}}
331 // CHECK-NEXT:    `-ParmVarDecl {{.+}} 'A<int>':'TTP::A<int>'{{$}}
332 // CHECK-NEXT:  FunctionProtoType {{.+}} 'auto (TT<T>) -> B<T>' dependent trailing_return cdecl{{$}}
333 // CHECK-NEXT:  |-InjectedClassNameType {{.+}} 'B<T>' dependent{{$}}
334 // CHECK-NEXT:  | `-CXXRecord {{.+}} 'B'{{$}}
335 // CHECK-NEXT:  `-ElaboratedType {{.+}} 'TT<T>' sugar dependent{{$}}
336 // CHECK-NEXT:    `-TemplateSpecializationType {{.+}} 'TT<T>' dependent{{$}}
337 // CHECK-NEXT:      |-name: 'TT':'template-parameter-0-1' qualified
338 // CHECK-NEXT:      | `-TemplateTemplateParmDecl {{.+}} depth 0 index 1
339 // CHECK-NEXT:      `-TemplateArgument type 'T':'type-parameter-0-0'{{$}}
340 // CHECK-NEXT:        `-TemplateTypeParmType {{.+}} 'T' dependent depth 0 index 0{{$}}
341 // CHECK-NEXT:          `-TemplateTypeParm {{.+}} 'T'{{$}}
342 
343 namespace GH64625 {
344 
345 template <class T> struct X {
346   T t[2];
347 };
348 
349 X x = {{1, 2}};
350 
351 // CHECK-LABEL: Dumping GH64625::<deduction guide for X>:
352 // CHECK-NEXT: FunctionTemplateDecl {{.+}} <{{.+}}:[[#@LINE - 7]]:1, col:27> col:27 implicit <deduction guide for X>
353 // CHECK-NEXT: |-TemplateTypeParmDecl {{.+}} <col:11, col:17> col:17 referenced class depth 0 index 0 T
354 // CHECK:      |-CXXDeductionGuideDecl {{.+}} <col:27> col:27 implicit <deduction guide for X> 'auto (T (&&)[2]) -> X<T>' aggregate
355 // CHECK-NEXT: | `-ParmVarDecl {{.+}} <col:27> col:27 'T (&&)[2]'
356 // CHECK-NEXT: `-CXXDeductionGuideDecl {{.+}} <col:27> col:27 implicit used <deduction guide for X> 'auto (int (&&)[2]) -> GH64625::X<int>' implicit_instantiation aggregate
357 // CHECK-NEXT:  |-TemplateArgument type 'int'
358 // CHECK-NEXT:  | `-BuiltinType {{.+}} 'int'
359 // CHECK-NEXT:  `-ParmVarDecl {{.+}} <col:27> col:27 'int (&&)[2]'
360 // CHECK-NEXT: FunctionProtoType {{.+}} 'auto (T (&&)[2]) -> X<T>' dependent trailing_return
361 // CHECK-NEXT: |-InjectedClassNameType {{.+}} 'X<T>' dependent
362 // CHECK-NEXT: | `-CXXRecord {{.+}} 'X'
363 // CHECK-NEXT: `-RValueReferenceType {{.+}} 'T (&&)[2]' dependent
364 // CHECK-NEXT:  `-ConstantArrayType {{.+}} 'T[2]' dependent 2
365 // CHECK-NEXT:    `-TemplateTypeParmType {{.+}} 'T' dependent depth 0 index 0
366 // CHECK-NEXT:      `-TemplateTypeParm {{.+}} 'T'
367 
368 template <class T, class U> struct TwoArrays {
369   T t[2];
370   U u[3];
371 };
372 
373 TwoArrays ta = {{1, 2}, {3, 4, 5}};
374 // CHECK-LABEL: Dumping GH64625::<deduction guide for TwoArrays>:
375 // CHECK-NEXT: FunctionTemplateDecl {{.+}} <{{.+}}:[[#@LINE - 7]]:1, col:36> col:36 implicit <deduction guide for TwoArrays>
376 // CHECK-NEXT: |-TemplateTypeParmDecl {{.+}} <col:11, col:17> col:17 referenced class depth 0 index 0 T
377 // CHECK-NEXT: |-TemplateTypeParmDecl {{.+}} <col:20, col:26> col:26 referenced class depth 0 index 1 U
378 // CHECK:      |-CXXDeductionGuideDecl {{.+}} <col:36> col:36 implicit <deduction guide for TwoArrays> 'auto (T (&&)[2], U (&&)[3]) -> TwoArrays<T, U>' aggregate
379 // CHECK-NEXT: | |-ParmVarDecl {{.+}} <col:36> col:36 'T (&&)[2]'
380 // CHECK-NEXT: | `-ParmVarDecl {{.+}} <col:36> col:36 'U (&&)[3]'
381 // CHECK-NEXT: `-CXXDeductionGuideDecl {{.+}} <col:36> col:36 implicit used <deduction guide for TwoArrays> 'auto (int (&&)[2], int (&&)[3]) -> GH64625::TwoArrays<int, int>' implicit_instantiation aggregate
382 // CHECK-NEXT:   |-TemplateArgument type 'int'
383 // CHECK-NEXT:   | `-BuiltinType {{.+}} 'int'
384 // CHECK-NEXT:   |-TemplateArgument type 'int'
385 // CHECK-NEXT:   | `-BuiltinType {{.+}} 'int'
386 // CHECK-NEXT:   |-ParmVarDecl {{.+}} <col:36> col:36 'int (&&)[2]'
387 // CHECK-NEXT:   `-ParmVarDecl {{.+}} <col:36> col:36 'int (&&)[3]'
388 // CHECK-NEXT: FunctionProtoType {{.+}} 'auto (T (&&)[2], U (&&)[3]) -> TwoArrays<T, U>' dependent trailing_return
389 // CHECK-NEXT: |-InjectedClassNameType {{.+}} 'TwoArrays<T, U>' dependent
390 // CHECK-NEXT: | `-CXXRecord {{.+}} 'TwoArrays'
391 // CHECK-NEXT: |-RValueReferenceType {{.+}} 'T (&&)[2]' dependent
392 // CHECK-NEXT: | `-ConstantArrayType {{.+}} 'T[2]' dependent 2
393 // CHECK-NEXT: |   `-TemplateTypeParmType {{.+}} 'T' dependent depth 0 index 0
394 // CHECK-NEXT: |     `-TemplateTypeParm {{.+}} 'T'
395 // CHECK-NEXT: `-RValueReferenceType {{.+}} 'U (&&)[3]' dependent
396 // CHECK-NEXT:   `-ConstantArrayType {{.+}} 'U[3]' dependent 3
397 // CHECK-NEXT:     `-TemplateTypeParmType {{.+}} 'U' dependent depth 0 index 1
398 // CHECK-NEXT:       `-TemplateTypeParm {{.+}} 'U'
399 
400 TwoArrays tb = {1, 2, {3, 4, 5}};
401 // CHECK:   |-CXXDeductionGuideDecl {{.+}} <col:36> col:36 implicit <deduction guide for TwoArrays> 'auto (T, T, U (&&)[3]) -> TwoArrays<T, U>' aggregate
402 // CHECK-NEXT: | |-ParmVarDecl {{.+}} <col:36> col:36 'T'
403 // CHECK-NEXT: | |-ParmVarDecl {{.+}} <col:36> col:36 'T'
404 // CHECK-NEXT: | `-ParmVarDecl {{.+}} <col:36> col:36 'U (&&)[3]'
405 // CHECK-NEXT: `-CXXDeductionGuideDecl {{.+}} <col:36> col:36 implicit used <deduction guide for TwoArrays> 'auto (int, int, int (&&)[3]) -> GH64625::TwoArrays<int, int>' implicit_instantiation aggregate
406 // CHECK-NEXT:   |-TemplateArgument type 'int'
407 // CHECK-NEXT:   | `-BuiltinType {{.+}} 'int'
408 // CHECK-NEXT:   |-TemplateArgument type 'int'
409 // CHECK-NEXT:   | `-BuiltinType {{.+}} 'int'
410 // CHECK-NEXT:   |-ParmVarDecl {{.+}} <col:36> col:36 'int'
411 // CHECK-NEXT:   |-ParmVarDecl {{.+}} <col:36> col:36 'int'
412 // CHECK-NEXT:   `-ParmVarDecl {{.+}} <col:36> col:36 'int (&&)[3]'
413 // CHECK-NEXT: FunctionProtoType {{.+}} 'auto (T, T, U (&&)[3]) -> TwoArrays<T, U>' dependent trailing_return
414 // CHECK-NEXT: |-InjectedClassNameType {{.+}} 'TwoArrays<T, U>' dependent
415 // CHECK-NEXT: | `-CXXRecord {{.+}} 'TwoArrays'
416 // CHECK-NEXT: |-TemplateTypeParmType {{.+}} 'T' dependent depth 0 index 0
417 // CHECK-NEXT: | `-TemplateTypeParm {{.+}} 'T'
418 // CHECK-NEXT: |-TemplateTypeParmType {{.+}} 'T' dependent depth 0 index 0
419 // CHECK-NEXT: | `-TemplateTypeParm {{.+}} 'T'
420 // CHECK-NEXT: `-RValueReferenceType {{.+}} 'U (&&)[3]' dependent
421 // CHECK-NEXT:   `-ConstantArrayType {{.+}} 'U[3]' dependent 3
422 // CHECK-NEXT:     `-TemplateTypeParmType {{.+}} 'U' dependent depth 0 index 1
423 // CHECK-NEXT:       `-TemplateTypeParm {{.+}} 'U'
424 
425 TwoArrays tc = {{1, 2}, 3, 4, 5};
426 // CHECK: |-CXXDeductionGuideDecl {{.+}} <col:36> col:36 implicit <deduction guide for TwoArrays> 'auto (T (&&)[2], U, U, U) -> TwoArrays<T, U>' aggregate
427 // CHECK-NEXT: | |-ParmVarDecl {{.+}} <col:36> col:36 'T (&&)[2]'
428 // CHECK-NEXT: | |-ParmVarDecl {{.+}} <col:36> col:36 'U'
429 // CHECK-NEXT: | |-ParmVarDecl {{.+}} <col:36> col:36 'U'
430 // CHECK-NEXT: | `-ParmVarDecl {{.+}} <col:36> col:36 'U'
431 // CHECK-NEXT: `-CXXDeductionGuideDecl {{.+}} <col:36> col:36 implicit used <deduction guide for TwoArrays> 'auto (int (&&)[2], int, int, int) -> GH64625::TwoArrays<int, int>' implicit_instantiation aggregate
432 // CHECK-NEXT:   |-TemplateArgument type 'int'
433 // CHECK-NEXT:   | `-BuiltinType {{.+}} 'int'
434 // CHECK-NEXT:   |-TemplateArgument type 'int'
435 // CHECK-NEXT:   | `-BuiltinType {{.+}} 'int'
436 // CHECK-NEXT:   |-ParmVarDecl {{.+}} <col:36> col:36 'int (&&)[2]'
437 // CHECK-NEXT:   |-ParmVarDecl {{.+}} <col:36> col:36 'int'
438 // CHECK-NEXT:   |-ParmVarDecl {{.+}} <col:36> col:36 'int'
439 // CHECK-NEXT:   `-ParmVarDecl {{.+}} <col:36> col:36 'int'
440 // CHECK-NEXT: FunctionProtoType {{.+}} 'auto (T (&&)[2], U, U, U) -> TwoArrays<T, U>' dependent trailing_return
441 // CHECK-NEXT: |-InjectedClassNameType {{.+}} 'TwoArrays<T, U>' dependent
442 // CHECK-NEXT: | `-CXXRecord {{.+}} 'TwoArrays'
443 // CHECK-NEXT: |-RValueReferenceType {{.+}} 'T (&&)[2]' dependent
444 // CHECK-NEXT: | `-ConstantArrayType {{.+}} 'T[2]' dependent 2
445 // CHECK-NEXT: |   `-TemplateTypeParmType {{.+}} 'T' dependent depth 0 index 0
446 // CHECK-NEXT: |     `-TemplateTypeParm {{.+}} 'T'
447 // CHECK-NEXT: |-TemplateTypeParmType {{.+}} 'U' dependent depth 0 index 1
448 // CHECK-NEXT: | `-TemplateTypeParm {{.+}} 'U'
449 // CHECK-NEXT: |-TemplateTypeParmType {{.+}} 'U' dependent depth 0 index 1
450 // CHECK-NEXT: | `-TemplateTypeParm {{.+}} 'U'
451 // CHECK-NEXT: `-TemplateTypeParmType {{.+}} 'U' dependent depth 0 index 1
452 // CHECK-NEXT:   `-TemplateTypeParm {{.+}} 'U'
453 
454 } // namespace GH64625
455 
456 namespace GH83368 {
457 
458 template <int N> struct A {
459   int f1[N];
460 };
461 
462 A a{.f1 = {1}};
463 
464 // CHECK-LABEL: Dumping GH83368::<deduction guide for A>:
465 // CHECK-NEXT: FunctionTemplateDecl 0x{{.+}} <{{.+}}:[[#@LINE - 7]]:1, col:25> col:25 implicit <deduction guide for A>
466 // CHECK-NEXT: |-NonTypeTemplateParmDecl {{.+}} <col:11, col:15> col:15 referenced 'int' depth 0 index 0 N
467 // CHECK:      |-CXXDeductionGuideDecl {{.+}} <col:25> col:25 implicit <deduction guide for A> 'auto (int (&&)[N]) -> A<N>' aggregate
468 // CHECK-NEXT: | `-ParmVarDecl {{.+}} <col:25> col:25 'int (&&)[N]'
469 // CHECK-NEXT: `-CXXDeductionGuideDecl {{.+}} <col:25> col:25 implicit used <deduction guide for A> 'auto (int (&&)[1]) -> GH83368::A<1>' implicit_instantiation aggregate
470 // CHECK-NEXT:   |-TemplateArgument integral '1'
471 // CHECK-NEXT:   `-ParmVarDecl {{.+}} <col:25> col:25 'int (&&)[1]'
472 // CHECK-NEXT: FunctionProtoType {{.+}} 'auto (int (&&)[N]) -> A<N>' dependent trailing_return
473 // CHECK-NEXT: |-InjectedClassNameType {{.+}} 'A<N>' dependent
474 // CHECK-NEXT: | `-CXXRecord {{.+}} 'A'
475 // CHECK-NEXT: `-RValueReferenceType {{.+}} 'int (&&)[N]' dependent
476 // CHECK-NEXT:   `-DependentSizedArrayType {{.+}} 'int[N]' dependent
477 // CHECK-NEXT:     |-BuiltinType {{.+}} 'int'
478 // CHECK-NEXT:     `-DeclRefExpr {{.+}} <col:10> 'int' NonTypeTemplateParm {{.+}} 'N' 'int'
479 
480 } // namespace GH83368
481 
482 namespace GH60777 {
483 
484 template <typename... Ts> constexpr bool True() { return true; }
485 
486 template <typename T>
487   requires(sizeof(T) > 1)
488 struct A {
489   template <typename... Ts>
490     requires(sizeof...(Ts) == 0)
491   A(T val, Ts... tail)
492     requires(True<Ts...>())
493   {}
494 };
495 
496 A a(42);
497 
498 // `requires (sizeof(T) > 1)` goes into the deduction guide together with
499 // `requires (True<Ts...>())`, while `requires(sizeof...(Ts) == 0)` goes into
500 // the template parameter list of the synthesized declaration.
501 
502 // CHECK-LABEL: Dumping GH60777::<deduction guide for A>:
503 // CHECK-NEXT: FunctionTemplateDecl 0x{{.+}} <{{.+}}> {{.+}} implicit <deduction guide for A>
504 // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <{{.+}}> col:20 referenced typename depth 0 index 0 T
505 // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <{{.+}}> col:25 typename depth 0 index 1 ... Ts
506 // CHECK-NEXT: |-ParenExpr 0x{{.+}} <{{.+}}> 'bool'
507 // CHECK-NEXT: | `-BinaryOperator 0x{{.+}} <{{.+}}> 'bool' '=='
508 // CHECK-NEXT: |   |-SizeOfPackExpr {{.+}} Ts
509 // CHECK-NEXT: |   | `-TemplateArgument type 'Ts...':'type-parameter-0-1...'
510 // CHECK-NEXT: |   |   `-PackExpansionType 0x{{.+}} 'Ts...' dependent
511 // CHECK-NEXT: |   |     `-TemplateTypeParmType 0x{{.+}} 'Ts' dependent contains_unexpanded_pack depth 0 index 1 pack
512 // CHECK-NEXT: |   |       `-TemplateTypeParm 0x{{.+}} 'Ts'
513 // CHECK-NEXT: |   `-ImplicitCastExpr {{.+}} <IntegralCast>
514 // CHECK-NEXT: |     `-IntegerLiteral 0x{{.+}} <{{.+}}> 'int' 0
515 // CHECK-NEXT: |-CXXDeductionGuideDecl 0x{{.+}} <{{.+}}> line:{{.+}} implicit <deduction guide for A> 'auto (T, Ts...) -> A<T>'
516 // CHECK-NEXT: | |-ParmVarDecl 0x{{.+}} <{{.+}}> col:{{.+}} val 'T'
517 // CHECK-NEXT: | |-ParmVarDecl 0x{{.+}} <{{.+}}> col:{{.+}} tail 'Ts...' pack
518 // CHECK-NEXT: | `-BinaryOperator 0x{{.+}} <{{.+}}> 'bool' '&&'
519 // CHECK-NEXT: |   |-ParenExpr 0x{{.+}} <{{.+}}> 'bool'
520 // CHECK-NEXT: |   | `-BinaryOperator 0x{{.+}} <{{.+}}> 'bool' '>'
521 // CHECK-NEXT: |   |   |-UnaryExprOrTypeTraitExpr {{.+}} sizeof 'T'
522 // CHECK-NEXT: |   |   `-ImplicitCastExpr {{.+}} <IntegralCast>
523 // CHECK-NEXT: |   |     `-IntegerLiteral 0x{{.+}} <{{.+}}> 'int' 1
524 // CHECK-NEXT: |   `-ParenExpr 0x{{.+}} <{{.+}}> '<dependent type>'
525 // CHECK-NEXT: |     `-CallExpr 0x{{.+}} <{{.+}}> '<dependent type>'
526 // CHECK-NEXT: |       `-UnresolvedLookupExpr 0x{{.+}} <col:14, col:24> '<dependent type>' {{.+}}
527 // CHECK-NEXT: |         `-TemplateArgument type 'Ts...':'type-parameter-0-1...'
528 // CHECK-NEXT: |           `-PackExpansionType 0x{{.+}} 'Ts...' dependent
529 // CHECK-NEXT: |             `-TemplateTypeParmType 0x{{.+}} 'Ts' dependent contains_unexpanded_pack depth 0 index 1 pack
530 // CHECK-NEXT: |               `-TemplateTypeParm 0x{{.+}} 'Ts'
531 
532 template <typename T>
533 struct B {
534   template <typename... Ts>
535   B(T val, Ts... tail)
536     requires(True<tail...>())
537   {}
538 };
539 
540 B b(42, 43);
541 // expected-error@-1 {{no viable constructor}} \
542 //   expected-note@-6 {{constraints not satisfied}} \
543 //   expected-note@-5 {{because substituted constraint expression is ill-formed}} \
544 //   expected-note@-6 {{implicit deduction guide declared as 'template <typename T, typename ...Ts> B(T val, Ts ...tail) -> B<T> requires (True<tail...>())'}} \
545 //   expected-note@-8 {{function template not viable}} \
546 //   expected-note@-8 {{implicit deduction guide declared as 'template <typename T> B(B<T>) -> B<T>'}}
547 
548 } // namespace GH60777
549 
550 // Examples from @hokein.
551 namespace GH98592 {
552 
553 template <class T> concept True = true;
554 double arr3[3];
555 
556 template <class T>
557 struct X {
558   const int size;
559   template <class U>
560   constexpr X(T, U(&)[3]) requires True<T> : size(sizeof(T)) {}
561 };
562 
563 template <typename T, typename U>
564 X(T, U (&)[3]) -> X<U>;
565 
566 constexpr X x(3, arr3);
567 
568 // The synthesized deduction guide is more constrained than the explicit one.
569 static_assert(x.size == 4);
570 
571 // CHECK-LABEL: Dumping GH98592::<deduction guide for X>:
572 // CHECK-NEXT: FunctionTemplateDecl 0x{{.+}} <{{.+}}> col:13 implicit <deduction guide for X>
573 // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <{{.+}}> col:17 referenced class depth 0 index 0 T
574 // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <{{.+}}> col:19 class depth 0 index 1 U
575 // CHECK-NEXT: |-CXXDeductionGuideDecl 0x{{.+}} <{{.+}}> col:13 implicit <deduction guide for X> 'auto (T, U (&)[3]) -> X<T>'
576 // CHECK-NEXT: | |-ParmVarDecl 0x{{.+}} <col:15> col:16 'T'
577 // CHECK-NEXT: | |-ParmVarDecl 0x{{.+}} <col:18, col:24> col:21 'U (&)[3]'
578 // CHECK-NEXT: | `-ConceptSpecializationExpr 0x{{.+}} <col:36, col:42> 'bool' Concept 0x{{.+}} 'True'
579 // CHECK-NEXT: |   |-ImplicitConceptSpecializationDecl 0x{{.+}} <{{.+}}> col:28
580 // CHECK-NEXT: |   | `-TemplateArgument type 'type-parameter-0-0'
581 // CHECK-NEXT: |   |   `-TemplateTypeParmType 0x{{.+}} 'type-parameter-0-0' dependent depth 0 index 0
582 // CHECK-NEXT: |   `-TemplateArgument <{{.+}}> type 'T':'type-parameter-0-0'
583 // CHECK-NEXT: |     `-TemplateTypeParmType 0x{{.+}} 'T' dependent depth 0 index 0
584 // CHECK-NEXT: |       `-TemplateTypeParm 0x{{.+}} 'T'
585 // CHECK-NEXT: `-CXXDeductionGuideDecl 0x{{.+}} <col:3, col:63> col:13 implicit used <deduction guide for X> 'auto (int, double (&)[3]) -> GH98592::X<int>' implicit_instantiation
586 // CHECK-NEXT:   |-TemplateArgument type 'int'
587 // CHECK-NEXT:   | `-BuiltinType 0x{{.+}} 'int'
588 // CHECK-NEXT:   |-TemplateArgument type 'double'
589 // CHECK-NEXT:   | `-BuiltinType 0x{{.+}} 'double'
590 // CHECK-NEXT:   |-ParmVarDecl 0x{{.+}} <col:15> col:16 'int'
591 // CHECK-NEXT:   |-ParmVarDecl 0x{{.+}} <col:18, col:24> col:21 'double (&)[3]'
592 // CHECK-NEXT:   `-ConceptSpecializationExpr 0x{{.+}} <col:36, col:42> 'bool' Concept 0x{{.+}} 'True'
593 // CHECK-NEXT:     |-ImplicitConceptSpecializationDecl 0x{{.+}} <{{.+}}> col:28
594 // CHECK-NEXT:     | `-TemplateArgument type 'type-parameter-0-0'
595 // CHECK-NEXT:     |   `-TemplateTypeParmType 0x{{.+}} 'type-parameter-0-0' dependent depth 0 index 0
596 // CHECK-NEXT:     `-TemplateArgument <{{.+}}> type 'T':'type-parameter-0-0'
597 // CHECK-NEXT:       `-TemplateTypeParmType 0x{{.+}} 'T' dependent depth 0 index 0
598 // CHECK-NEXT:         `-TemplateTypeParm 0x{{.+}} 'T'
599 
600 template <class T> requires True<T> struct Y {
601   const int size;
602   template <class U>
603   constexpr Y(T, U(&)[3]) : size(sizeof(T)) {}
604 };
605 
606 template <typename T, typename U> Y(T, U (&)[3]) -> Y<U>;
607 
608 constexpr Y y(3, arr3);
609 
610 // Likewise, the synthesized deduction guide should be preferred
611 // according to [over.match.class.deduct]p1.
612 static_assert(y.size == 4);
613 
614 // Dumping GH98592::<deduction guide for Y>:
615 // FunctionTemplateDecl 0x{{.+}} <{{.+}}> col:13 implicit <deduction guide for Y>
616 // |-TemplateTypeParmDecl 0x{{.+}} <{{.+}}> col:17 referenced class depth 0 index 0 T
617 // |-TemplateTypeParmDecl 0x{{.+}} <{{.+}}> col:19 class depth 0 index 1 U
618 // |-CXXDeductionGuideDecl 0x{{.+}} <{{.+}}> col:13 implicit <deduction guide for Y> 'auto (T, U (&)[3]) -> Y<T>'
619 // | |-ParmVarDecl 0x{{.+}} <col:15> col:16 'T'
620 // | |-ParmVarDecl 0x{{.+}} <col:18, col:24> col:21 'U (&)[3]'
621 // | `-ConceptSpecializationExpr 0x{{.+}} <{{.+}}> 'bool' Concept 0x{{.+}} 'True'
622 // |   |-ImplicitConceptSpecializationDecl 0x{{.+}} <{{.+}}> col:28
623 // |   | `-TemplateArgument type 'type-parameter-0-0'
624 // |   |   `-TemplateTypeParmType 0x{{.+}} 'type-parameter-0-0' dependent depth 0 index 0
625 // |   `-TemplateArgument <{{.+}}> type 'T':'type-parameter-0-0'
626 // |     `-TemplateTypeParmType 0x{{.+}} 'T' dependent depth 0 index 0
627 // |       `-TemplateTypeParm 0x{{.+}} 'T'
628 // `-CXXDeductionGuideDecl 0x{{.+}} <{{.+}}> col:13 implicit used <deduction guide for Y> 'auto (int, double (&)[3]) -> GH98592::Y<int>' implicit_instantiation
629 //   |-TemplateArgument type 'int'
630 //   | `-BuiltinType 0x{{.+}} 'int'
631 //   |-TemplateArgument type 'double'
632 //   | `-BuiltinType 0x{{.+}} 'double'
633 //   |-ParmVarDecl 0x{{.+}} <col:15> col:16 'int'
634 //   |-ParmVarDecl 0x{{.+}} <col:18, col:24> col:21 'double (&)[3]'
635 //   `-ConceptSpecializationExpr 0x{{.+}} <{{.+}}> 'bool' Concept 0x{{.+}} 'True'
636 //     |-ImplicitConceptSpecializationDecl 0x{{.+}} <{{.+}}> col:28
637 //     | `-TemplateArgument type 'type-parameter-0-0'
638 //     |   `-TemplateTypeParmType 0x{{.+}} 'type-parameter-0-0' dependent depth 0 index 0
639 //     `-TemplateArgument <{{.+}}> type 'T':'type-parameter-0-0'
640 //       `-TemplateTypeParmType 0x{{.+}} 'T' dependent depth 0 index 0
641 //         `-TemplateTypeParm 0x{{.+}} 'T'
642 
643 } // namespce GH98592
644 
645 namespace GH122134 {
646 
647 template <class, class>
648 concept Constraint = true;
649 
650 template <class T, int> struct Struct {
651   Struct(Constraint<T> auto) {}
652 };
653 
654 template <int N = 0> using Test = Struct<int, N>;
655 
656 Test test(42);
657 
658 // CHECK-LABEL: Dumping GH122134::<deduction guide for Test>:
659 // CHECK-NEXT: FunctionTemplateDecl {{.*}} implicit <deduction guide for Test>
660 // CHECK-NEXT: |-NonTypeTemplateParmDecl {{.*}} 'int' depth 0 index 0 N
661 // CHECK-NEXT: | `-TemplateArgument {{.*}} expr '0'
662 // CHECK-NEXT: |   `-IntegerLiteral {{.*}} 'int' 0
663 // CHECK-NEXT: |-TemplateTypeParmDecl {{.*}} Concept {{.*}} 'Constraint' depth 0 index 1 auto:1
664 // CHECK-NEXT: | `-ConceptSpecializationExpr {{.*}} 'bool' Concept {{.*}} 'Constraint'
665 // CHECK-NEXT: |   |-ImplicitConceptSpecializationDecl {{.*}}
666 // CHECK-NEXT: |   | |-TemplateArgument type 'type-parameter-0-1'
667 // CHECK-NEXT: |   | | `-TemplateTypeParmType {{.*}} 'type-parameter-0-1' dependent depth 0 index 1
668 // CHECK-NEXT: |   | `-TemplateArgument type 'int'
669 // CHECK-NEXT: |   |   `-BuiltinType {{.*}} 'int'
670 // CHECK-NEXT: |   |-TemplateArgument {{.*}} type 'auto:1':'type-parameter-0-1'
671 // CHECK-NEXT: |   | `-TemplateTypeParmType {{.*}} 'auto:1' dependent depth 0 index 1
672 // CHECK-NEXT: |   |   `-TemplateTypeParm {{.*}} 'auto:1'
673 // CHECK-NEXT: |   `-TemplateArgument {{.*}} type 'int'
674 // CHECK-NEXT: |     `-BuiltinType {{.*}} 'int'
675 // CHECK-NEXT: |-TypeTraitExpr {{.*}} 'bool' __is_deducible
676 // CHECK-NEXT: | |-DeducedTemplateSpecializationType {{.*}} 'GH122134::Test' dependent
677 // CHECK-NEXT: | | `-name: 'GH122134::Test'
678 // CHECK-NEXT: | |   `-TypeAliasTemplateDecl {{.*}} Test
679 // CHECK-NEXT: | `-TemplateSpecializationType {{.*}} 'Struct<int, N>' dependent
680 // CHECK-NEXT: |   |-name: 'Struct':'GH122134::Struct' qualified
681 // CHECK-NEXT: |   | `-ClassTemplateDecl {{.*}} Struct
682 // CHECK-NEXT: |   |-TemplateArgument type 'int'
683 // CHECK-NEXT: |   | `-SubstTemplateTypeParmType {{.*}} 'int' sugar class depth 0 index 0 T
684 // CHECK-NEXT: |   |   |-FunctionTemplate {{.*}} '<deduction guide for Struct>'
685 // CHECK-NEXT: |   |   `-BuiltinType {{.*}} 'int'
686 // CHECK-NEXT: |   `-TemplateArgument expr 'N'
687 // CHECK-NEXT: |     `-SubstNonTypeTemplateParmExpr {{.*}} 'int'
688 // CHECK-NEXT: |       |-NonTypeTemplateParmDecl {{.*}} 'int' depth 0 index 1
689 // CHECK-NEXT: |       `-DeclRefExpr {{.*}} 'int' NonTypeTemplateParm {{.*}} 'N' 'int'
690 // CHECK-NEXT: |-CXXDeductionGuideDecl {{.*}} implicit <deduction guide for Test> 'auto (auto:1) -> Struct<int, N>'
691 // CHECK-NEXT: | `-ParmVarDecl {{.*}} 'auto:1'
692 
693 } // namespace GH122134
694