On Tue, Mar 17, 2020 at 03:54:57PM -0400, Jason Merrill via Gcc-patches wrote:
> How about always diagnosing this here, and moving the deduction guide code
> in grokfndecl up above set_decl_namespace to avoid a duplicate diagnostic?
I've tried that as:
--- gcc/cp/decl.c.jj 2020-03-16 22:56:46.787172869 +0100
+++ gcc/cp/decl.c 2020-03-17 21:29:17.812732717 +0100
@@ -9506,6 +9506,27 @@ grokfndecl (tree ctype,
inlinep &= ~8;
}
+ if (deduction_guide_p (decl))
+ {
+ if (!DECL_NAMESPACE_SCOPE_P (decl))
+ {
+ error_at (location, "deduction guide %qD must be declared at "
+ "namespace scope", decl);
+ return NULL_TREE;
+ }
+ tree type = TREE_TYPE (DECL_NAME (decl));
+ if (CP_DECL_CONTEXT (decl) != CP_TYPE_CONTEXT (type))
+ {
+ error_at (location, "deduction guide %qD must be declared in the "
+ "same scope as %qT", decl, type);
+ inform (location_of (type), " declared here");
+ return NULL_TREE;
+ }
+ if (funcdef_flag)
+ error_at (location,
+ "deduction guide %qD must not have a function body", decl);
+ }
+
/* If this decl has namespace scope, set that up. */
if (in_namespace)
set_decl_namespace (decl, in_namespace, friendp);
@@ -9636,20 +9657,8 @@ grokfndecl (tree ctype,
}
}
- if (deduction_guide_p (decl))
- {
- if (!DECL_NAMESPACE_SCOPE_P (decl))
- {
- error_at (location, "deduction guide %qD must be declared at "
- "namespace scope", decl);
- return NULL_TREE;
- }
- if (funcdef_flag)
- error_at (location,
- "deduction guide %qD must not have a function body", decl);
- }
- else if (IDENTIFIER_ANY_OP_P (DECL_NAME (decl))
- && !grok_op_properties (decl, /*complain=*/true))
+ if (IDENTIFIER_ANY_OP_P (DECL_NAME (decl))
+ && !grok_op_properties (decl, /*complain=*/true))
return NULL_TREE;
else if (UDLIT_OPER_P (DECL_NAME (decl)))
{
--- gcc/testsuite/g++.dg/cpp1z/class-deduction9.C.jj 2020-01-12
11:54:37.126402652 +0100
+++ gcc/testsuite/g++.dg/cpp1z/class-deduction9.C 2020-03-17
21:29:53.842207083 +0100
@@ -10,7 +10,7 @@ namespace N {
}
template <class T>
-N::A(T) -> N::A<T>; // { dg-error "should have been declared inside .N" }
+N::A(T) -> N::A<T>; // { dg-error "must be declared in the same scope as"
}
namespace N {
template <class T>
--- gcc/testsuite/g++.dg/cpp1z/class-deduction72.C.jj 2020-03-17
21:26:00.566610331 +0100
+++ gcc/testsuite/g++.dg/cpp1z/class-deduction72.C 2020-03-17
21:26:00.566610331 +0100
@@ -0,0 +1,11 @@
+// PR c++/91759
+// { dg-do compile { target c++17 } }
+
+namespace N {
+ template <typename T>
+ struct X{ X(int); }; // { dg-message "declared here" }
+}
+
+using N::X;
+
+X(int) -> X<int>; // { dg-error "must be declared in the same scope as" }
but that fails with
Excess errors:
/usr/src/gcc/obj/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/stl_pair.h:459:40:
error: deduction guide 'pair(_T1, _T2)-> std::pair<_T1, _T2>' must be declared
in the same scope as 'std::pair<_T1, _T2>'
/usr/src/gcc/obj/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/stl_vector.h:1873:5:
error: deduction guide 'vector(_InputIterator, _InputIterator, _Allocator)->
std::vector<_ValT, _Allocator>' must be declared in the same scope as
'std::vector<_Tp, _Alloc>'
on various testcases.
I've tried next:
--- gcc/cp/decl.c.jj 2020-03-16 22:56:46.787172869 +0100
+++ gcc/cp/decl.c 2020-03-17 22:00:13.897648589 +0100
@@ -9506,6 +9506,36 @@ grokfndecl (tree ctype,
inlinep &= ~8;
}
+ if (deduction_guide_p (decl))
+ {
+ if (!DECL_NAMESPACE_SCOPE_P (decl))
+ {
+ error_at (location, "deduction guide %qD must be declared at "
+ "namespace scope", decl);
+ return NULL_TREE;
+ }
+ tree type = TREE_TYPE (DECL_NAME (decl));
+ tree ctx = NULL_TREE;
+ if (in_namespace)
+ ctx = ORIGINAL_NAMESPACE (in_namespace);
+ else if (!ctype)
+ ctx = current_decl_namespace ();
+ if (ctx)
+ ctx = FROB_CONTEXT (ctx);
+ if (SCOPE_FILE_SCOPE_P (ctx))
+ ctx = global_namespace;
+ if (CP_TYPE_CONTEXT (type) != ctx)
+ {
+ error_at (location, "deduction guide %qD must be declared in the "
+ "same scope as %qT", decl, type);
+ inform (location_of (type), " declared here");
+ return NULL_TREE;
+ }
+ if (funcdef_flag)
+ error_at (location,
+ "deduction guide %qD must not have a function body", decl);
+ }
+
/* If this decl has namespace scope, set that up. */
if (in_namespace)
set_decl_namespace (decl, in_namespace, friendp);
@@ -9636,20 +9666,8 @@ grokfndecl (tree ctype,
}
}
- if (deduction_guide_p (decl))
- {
- if (!DECL_NAMESPACE_SCOPE_P (decl))
- {
- error_at (location, "deduction guide %qD must be declared at "
- "namespace scope", decl);
- return NULL_TREE;
- }
- if (funcdef_flag)
- error_at (location,
- "deduction guide %qD must not have a function body", decl);
- }
- else if (IDENTIFIER_ANY_OP_P (DECL_NAME (decl))
- && !grok_op_properties (decl, /*complain=*/true))
+ if (IDENTIFIER_ANY_OP_P (DECL_NAME (decl))
+ && !grok_op_properties (decl, /*complain=*/true))
return NULL_TREE;
else if (UDLIT_OPER_P (DECL_NAME (decl)))
{
--- gcc/testsuite/g++.dg/cpp1z/class-deduction72.C.jj 2020-03-17
21:26:00.566610331 +0100
+++ gcc/testsuite/g++.dg/cpp1z/class-deduction72.C 2020-03-17
21:26:00.566610331 +0100
@@ -0,0 +1,11 @@
+// PR c++/91759
+// { dg-do compile { target c++17 } }
+
+namespace N {
+ template <typename T>
+ struct X{ X(int); }; // { dg-message "declared here" }
+}
+
+using N::X;
+
+X(int) -> X<int>; // { dg-error "must be declared in the same scope as" }
--- gcc/testsuite/g++.dg/cpp1z/class-deduction9.C.jj 2020-01-12
11:54:37.126402652 +0100
+++ gcc/testsuite/g++.dg/cpp1z/class-deduction9.C 2020-03-17
21:29:53.842207083 +0100
@@ -10,7 +10,7 @@ namespace N {
}
template <class T>
-N::A(T) -> N::A<T>; // { dg-error "should have been declared inside .N" }
+N::A(T) -> N::A<T>; // { dg-error "must be declared in the same scope as"
}
namespace N {
template <class T>
but that FAILs the class-deduction9.C test with the adjustment,
reports the older "should have been"... error instead, because the computed
ctx is the N namespace, which is also what set_decl_namespace sets, but then
it fails some lookup and emits this message.
Jakub
