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* [gcc r13-6989] c++: ICE with loopy var tmpl auto deduction [PR109300]
@ 2023-04-03 22:50 Patrick Palka
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From: Patrick Palka @ 2023-04-03 22:50 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:c37ed38ada788ae410c48ec6d8c9b5d9f32ab8cf
commit r13-6989-gc37ed38ada788ae410c48ec6d8c9b5d9f32ab8cf
Author: Patrick Palka <ppalka@redhat.com>
Date: Mon Apr 3 18:49:37 2023 -0400
c++: ICE with loopy var tmpl auto deduction [PR109300]
Now that we resolve non-dependent variable template-ids ahead of time,
cp_finish_decl needs to handle a new invalid situation: we can end up
trying to instantiate a variable template with deduced type before we
fully parsed its initializer.
PR c++/109300
gcc/cp/ChangeLog:
* decl.cc (cp_finish_decl): Diagnose ordinary auto deduction
with no initializer, instead of asserting.
gcc/testsuite/ChangeLog:
* g++.dg/cpp1y/var-templ79.C: New test.
Diff:
---
gcc/cp/decl.cc | 15 ++++++++++++++-
gcc/testsuite/g++.dg/cpp1y/var-templ79.C | 5 +++++
2 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 20b980f68c8..5369714f9b3 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -8276,7 +8276,20 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
return;
}
- gcc_assert (CLASS_PLACEHOLDER_TEMPLATE (auto_node));
+ if (CLASS_PLACEHOLDER_TEMPLATE (auto_node))
+ /* Class deduction with no initializer is OK. */;
+ else
+ {
+ /* Ordinary auto deduction without an initializer, a situation
+ which grokdeclarator already detects and rejects for the most
+ part. But we can still get here if we're instantiating a
+ variable template before we've fully parsed (and attached) its
+ initializer, e.g. template<class> auto x = x<int>; */
+ error_at (DECL_SOURCE_LOCATION (decl),
+ "declaration of %q#D has no initializer", decl);
+ TREE_TYPE (decl) = error_mark_node;
+ return;
+ }
}
d_init = init;
if (d_init)
diff --git a/gcc/testsuite/g++.dg/cpp1y/var-templ79.C b/gcc/testsuite/g++.dg/cpp1y/var-templ79.C
new file mode 100644
index 00000000000..3c0d276153a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/var-templ79.C
@@ -0,0 +1,5 @@
+// PR c++/109300
+// { dg-do compile { target c++14 } }
+
+template<class>
+auto x = x<int>; // { dg-error "" }
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