On 8/14/26 4:40 PM, Wang Jinghao wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu.
-- >8 --
Contract conditions are parsed outside the function body, so
`at_function_scope_p()' is false when their parameter pack expansions
are formed. However, function parameter packs in contract conditions
should use local specializations during substitution, just as they do
within a function body.
Does it work to change at_function_scope_p() to local_bindings_p()? The
latter seems to be the more relevant question.
...it seems not yet, because local_bindings_p wrongly returns false for
contract scope, so we need to move sk_contract before sk_function_parms
in scope_kind, as attached.
gcc/testsuite/ChangeLog:
* g++.dg/contracts/cpp26/pr125645.C: New test.
So perhaps fold1.C.
From fa87b30937d166715324eb1a4b6b25e501e0c8b6 Mon Sep 17 00:00:00 2001
From: Jason Merrill <[email protected]>
Date: Mon, 17 Aug 2026 09:06:09 -0400
Subject: [PATCH] c++: correct local_bindings_p for contracts
To: [email protected]
gcc/cp/ChangeLog:
* name-lookup.h (enum scope_kind): Move sk_contract before
sk_function_parms.
* pt.cc (make_pack_expansion): Use local_bindings_p.
---
gcc/cp/name-lookup.h | 6 ++++--
gcc/cp/pt.cc | 5 ++---
2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/gcc/cp/name-lookup.h b/gcc/cp/name-lookup.h
index a0e7e10795e..af3fd927f3d 100644
--- a/gcc/cp/name-lookup.h
+++ b/gcc/cp/name-lookup.h
@@ -239,6 +239,8 @@ enum scope_kind {
sk_cond, /* The scope of the variable declared in the condition
of an if or switch statement. */
sk_stmt_expr, /* GNU statement expression block. */
+ sk_contract, /* A C++26 contract-assertion scope.
+ [basic.scope.contract] */
sk_function_parms, /* The scope containing function parameters. */
sk_class, /* The scope containing the members of a class. */
sk_scoped_enum, /* The scope containing the enumerators of a C++11
@@ -253,8 +255,8 @@ enum scope_kind {
sk_transaction, /* A synchronized or atomic statement. */
sk_omp, /* An OpenMP structured block. */
sk_lambda, /* A lambda scope. */
- sk_contract, /* A C++26 contract-assertion scope.
- [basic.scope.contract] */
+ /* Note that scopes for which local_bindings_p should be true must precede
+ sk_function_parms. */
sk_count /* Number of scope_kind enumerations. */
};
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 50f9fae49d1..6791795e26a 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -4402,7 +4402,7 @@ make_pack_expansion (tree arg, tsubst_flags_t complain)
purpose = cxx_make_type (TYPE_PACK_EXPANSION);
PACK_EXPANSION_PATTERN (purpose) = TREE_PURPOSE (arg);
PACK_EXPANSION_PARAMETER_PACKS (purpose) = parameter_packs;
- PACK_EXPANSION_LOCAL_P (purpose) = at_function_scope_p ();
+ PACK_EXPANSION_LOCAL_P (purpose) = local_bindings_p ();
/* Just use structural equality for these TYPE_PACK_EXPANSIONS;
they will rarely be compared to anything. */
@@ -4455,8 +4455,7 @@ make_pack_expansion (tree arg, tsubst_flags_t complain)
/* Contract conditions are parsed outside a function body but function
parameter pack expansions in them must use the instantiated parameters
rather than dummy declarations. */
- PACK_EXPANSION_LOCAL_P (result)
- = at_function_scope_p () || processing_contract_condition;
+ PACK_EXPANSION_LOCAL_P (result) = local_bindings_p ();
if (ppd.found_extra_args_tree_p)
/* If the pattern of this pack expansion contains a subtree that has
the extra args mechanism for avoiding partial instantiation, then
--
2.55.0
