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| author | Marek Polacek <polacek@redhat.com> | 2020-06-26 12:40:59 -0400 |
|---|---|---|
| committer | Marek Polacek <polacek@redhat.com> | 2020-06-29 11:01:58 -0400 |
| commit | 54980635c537f3130481da2d8b1109c775db8bb0 (patch) | |
| tree | fa66658f274fc2274a323c83c1fc709fc3232a62 /gcc/cp | |
| parent | b1005f553d3543bb56dc6b9b34ee35455d697ca4 (diff) | |
| download | gcc-54980635c537f3130481da2d8b1109c775db8bb0.zip gcc-54980635c537f3130481da2d8b1109c775db8bb0.tar.gz gcc-54980635c537f3130481da2d8b1109c775db8bb0.tar.bz2 | |
c++: Check uniqueness of concepts/variable templates [PR94553]
This patch wraps up PR94553. Variable template names have no C
compatibility implications so they should be unique in their
declarative region. It occurred to me that this applies to concepts
as well. This is not specified in [basic.scope.declarative]/4.2
but that seems like a bug in the standard.
I couldn't use variable_template_p because that uses PRIMARY_TEMPLATE_P
which uses DECL_PRIMARY_TEMPLATE and that might not have been set up yet
(push_template_decl hasn't yet been called). PRIMARY_TEMPLATE_P is
important to distinguish between a variable template and a variable in a
function template. But I think we don't have to worry about that in
duplicate_decls: a template declaration cannot appear at block scope,
and additional checks in duplicate_decls suggest that it won't ever
see a TEMPLATE_DECL for a variable in a function template. So
checking that the DECL_TEMPLATE_RESULT is a VAR_DECL seems to be fine.
I could have added a default argument to variable_template_p too to
avoid checking PRIMARY_TEMPLATE_P but it didn't seem worth the effort.
gcc/cp/ChangeLog:
PR c++/94553
* decl.c (duplicate_decls): Make sure a concept or a variable
template is unique in its declarative region.
gcc/testsuite/ChangeLog:
PR c++/94553
* g++.dg/cpp1y/pr68578.C: Adjust dg-error.
* g++.dg/cpp1y/var-templ66.C: New test.
* g++.dg/cpp2a/concepts-redecl1.C: New test.
Diffstat (limited to 'gcc/cp')
| -rw-r--r-- | gcc/cp/decl.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index 3afad5c..45c871a 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -1679,6 +1679,16 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend) else if (DECL_TYPE_TEMPLATE_P (olddecl) || DECL_TYPE_TEMPLATE_P (newdecl)) /* Class template conflicts. */; + else if ((TREE_CODE (olddecl) == TEMPLATE_DECL + && DECL_TEMPLATE_RESULT (olddecl) + && TREE_CODE (DECL_TEMPLATE_RESULT (olddecl)) == VAR_DECL) + || (TREE_CODE (newdecl) == TEMPLATE_DECL + && DECL_TEMPLATE_RESULT (newdecl) + && TREE_CODE (DECL_TEMPLATE_RESULT (newdecl)) == VAR_DECL)) + /* Variable template conflicts. */; + else if (concept_definition_p (olddecl) + || concept_definition_p (newdecl)) + /* Concept conflicts. */; else if ((TREE_CODE (newdecl) == FUNCTION_DECL && DECL_FUNCTION_TEMPLATE_P (olddecl)) || (TREE_CODE (olddecl) == FUNCTION_DECL @@ -1701,7 +1711,7 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend) " literal operator template", newdecl); else return NULL_TREE; - + inform (olddecl_loc, "previous declaration %q#D", olddecl); return error_mark_node; } |