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 return type
before we fully parsed (and attached) its initializer.
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this OK for
trunK?
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.
---
gcc/cp/decl.cc | 15 ++++++++++++++-
gcc/testsuite/g++.dg/cpp1y/var-templ79.C | 5 +++++
2 files changed, 19 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp1y/var-templ79.C
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 20b980f68c8..2c91693b99d 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 catches 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 "" }
--
2.40.0.130.g27d43aaaf5
