Message ID | ZtnJ-VP7HlJHOnce@redhat.com |
---|---|
State | New |
Headers | show |
Series | [v3] c++: fn redecl in fn scope wrongly accepted [PR116239] | expand |
On 9/5/24 11:10 AM, Marek Polacek wrote: > On Thu, Sep 05, 2024 at 10:42:22AM -0400, Jason Merrill wrote: >> On 9/4/24 1:18 PM, Marek Polacek wrote: >>> On Wed, Sep 04, 2024 at 12:28:49PM -0400, Jason Merrill wrote: >> >>>>> + if (!validate_constexpr_redeclaration (alias, decl)) >>>>> + return; >>>>> + >>>>> retrofit_lang_decl (decl); >>>>> DECL_LOCAL_DECL_ALIAS (decl) = alias; >>>>> } >>>> >>>> I don't think we need this in the case that we built a new alias and pushed >>>> it; in that case alias is built from decl, and should certainly match >>>> already. So let's put this call before we decide to build a new alias, >>>> either in the loop or just after it. >>> >>> That's right. How about this? >> >> Hmm, I'd still prefer to have it *before* the !alias case for locality; >> putting it as an else to a 66-line if seems obscure. >> >> But OK however. > > Ah, let me change it. Still OK? dg.exp passed. OK, thanks. > -- >8 -- > Redeclaration such as > > void f(void); > consteval void f(void); > > is invalid. In a namespace scope, we detect the collision in > validate_constexpr_redeclaration, but not when one declaration is > at block scope. > > When we have > > void f(void); > void g() { consteval void f(void); } > > we call pushdecl on the second f and call push_local_extern_decl_alias. > It finds the namespace-scope f: > > for (ovl_iterator iter (binding); iter; ++iter) > if (decls_match (decl, *iter, /*record_versions*/false)) > { > alias = *iter; > break; > } > > but decls_match says they match so we just set DECL_LOCAL_DECL_ALIAS > (and do not call another pushdecl leading to duplicate_decls which > would detect mismatching return types, for example). I don't think > we want to change decls_match, so a simple fix is to detect the > problem in push_local_extern_decl_alias. > > PR c++/116239 > > gcc/cp/ChangeLog: > > * cp-tree.h (validate_constexpr_redeclaration): Declare. > * decl.cc (validate_constexpr_redeclaration): No longer static. > * name-lookup.cc (push_local_extern_decl_alias): Call > validate_constexpr_redeclaration. > > gcc/testsuite/ChangeLog: > > * g++.dg/diagnostic/redeclaration-6.C: New test. > --- > gcc/cp/cp-tree.h | 1 + > gcc/cp/decl.cc | 2 +- > gcc/cp/name-lookup.cc | 2 ++ > .../g++.dg/diagnostic/redeclaration-6.C | 34 +++++++++++++++++++ > 4 files changed, 38 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/diagnostic/redeclaration-6.C > > diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h > index 2eeb5e3e8b1..1a763b683de 100644 > --- a/gcc/cp/cp-tree.h > +++ b/gcc/cp/cp-tree.h > @@ -6992,6 +6992,7 @@ extern bool member_like_constrained_friend_p (tree); > extern bool fns_correspond (tree, tree); > extern int decls_match (tree, tree, bool = true); > extern bool maybe_version_functions (tree, tree, bool); > +extern bool validate_constexpr_redeclaration (tree, tree); > extern bool merge_default_template_args (tree, tree, bool); > extern tree duplicate_decls (tree, tree, > bool hiding = false, > diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc > index 7bad3047ad9..f4128dbccdf 100644 > --- a/gcc/cp/decl.cc > +++ b/gcc/cp/decl.cc > @@ -1412,7 +1412,7 @@ check_redeclaration_exception_specification (tree new_decl, > /* Return true if OLD_DECL and NEW_DECL agree on constexprness. > Otherwise issue diagnostics. */ > > -static bool > +bool > validate_constexpr_redeclaration (tree old_decl, tree new_decl) > { > old_decl = STRIP_TEMPLATE (old_decl); > diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc > index 7a6cc244c15..cd3947cbe4f 100644 > --- a/gcc/cp/name-lookup.cc > +++ b/gcc/cp/name-lookup.cc > @@ -3637,6 +3637,8 @@ push_local_extern_decl_alias (tree decl) > if (decls_match (decl, *iter, /*record_versions*/false)) > { > alias = *iter; > + if (!validate_constexpr_redeclaration (alias, decl)) > + return; > break; > } > > diff --git a/gcc/testsuite/g++.dg/diagnostic/redeclaration-6.C b/gcc/testsuite/g++.dg/diagnostic/redeclaration-6.C > new file mode 100644 > index 00000000000..ed8d4af7792 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/diagnostic/redeclaration-6.C > @@ -0,0 +1,34 @@ > +// PR c++/116239 > +// { dg-do compile { target c++20 } } > + > +consteval void f1(); > +void f2(); > +constexpr void f3(); > +void f4(); > +consteval void f5(); > +constexpr void f6(); > + > +void > +g () > +{ > + void f1(); // { dg-error "differs in .consteval." } > + consteval void f2(); // { dg-error "differs in .consteval." } > + > + void f3(); // { dg-error "differs in .constexpr." } > + constexpr void f4(); // { dg-error "differs in .constexpr." } > + > + consteval void f5(); > + constexpr void f6(); > + > + void f7(); > + consteval void f7(); // { dg-error "differs in .consteval." } > + > + consteval void f8(); > + void f8(); // { dg-error "differs in .consteval." } > + > + void f9(); > + constexpr void f9(); // { dg-error "differs in .constexpr." } > + > + constexpr void f10(); > + void f10(); // { dg-error "differs in .constexpr." } > +} > > base-commit: ae88e91938af364ef5613e5461b12b484b578bc5
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 2eeb5e3e8b1..1a763b683de 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -6992,6 +6992,7 @@ extern bool member_like_constrained_friend_p (tree); extern bool fns_correspond (tree, tree); extern int decls_match (tree, tree, bool = true); extern bool maybe_version_functions (tree, tree, bool); +extern bool validate_constexpr_redeclaration (tree, tree); extern bool merge_default_template_args (tree, tree, bool); extern tree duplicate_decls (tree, tree, bool hiding = false, diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc index 7bad3047ad9..f4128dbccdf 100644 --- a/gcc/cp/decl.cc +++ b/gcc/cp/decl.cc @@ -1412,7 +1412,7 @@ check_redeclaration_exception_specification (tree new_decl, /* Return true if OLD_DECL and NEW_DECL agree on constexprness. Otherwise issue diagnostics. */ -static bool +bool validate_constexpr_redeclaration (tree old_decl, tree new_decl) { old_decl = STRIP_TEMPLATE (old_decl); diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc index 7a6cc244c15..cd3947cbe4f 100644 --- a/gcc/cp/name-lookup.cc +++ b/gcc/cp/name-lookup.cc @@ -3637,6 +3637,8 @@ push_local_extern_decl_alias (tree decl) if (decls_match (decl, *iter, /*record_versions*/false)) { alias = *iter; + if (!validate_constexpr_redeclaration (alias, decl)) + return; break; } diff --git a/gcc/testsuite/g++.dg/diagnostic/redeclaration-6.C b/gcc/testsuite/g++.dg/diagnostic/redeclaration-6.C new file mode 100644 index 00000000000..ed8d4af7792 --- /dev/null +++ b/gcc/testsuite/g++.dg/diagnostic/redeclaration-6.C @@ -0,0 +1,34 @@ +// PR c++/116239 +// { dg-do compile { target c++20 } } + +consteval void f1(); +void f2(); +constexpr void f3(); +void f4(); +consteval void f5(); +constexpr void f6(); + +void +g () +{ + void f1(); // { dg-error "differs in .consteval." } + consteval void f2(); // { dg-error "differs in .consteval." } + + void f3(); // { dg-error "differs in .constexpr." } + constexpr void f4(); // { dg-error "differs in .constexpr." } + + consteval void f5(); + constexpr void f6(); + + void f7(); + consteval void f7(); // { dg-error "differs in .consteval." } + + consteval void f8(); + void f8(); // { dg-error "differs in .consteval." } + + void f9(); + constexpr void f9(); // { dg-error "differs in .constexpr." } + + constexpr void f10(); + void f10(); // { dg-error "differs in .constexpr." } +}