On 2/6/20 7:30 PM, Marek Polacek wrote:
In ed4f2c001a883b2456fc607a33f1c59f9c4ee65d I changed the call to
fold_non_dependent_expr in check_narrowing to maybe_constant_value.
That was the wrong thing to do as these tests show: check_narrowing
bails out for dependent expressions but we can still have template
codes like CAST_EXPR that don't have anything dependent in it so are
considered non-dependent. But cxx_eval_* don't grok template codes,
so we need to call fold_non_dependent_expr instead which knows what
to do with template codes. (I fully accept a "told you so".)
I'm passing tf_none to it, otherwise we'd emit a bogus error for
constexpr-ex4.C: there INIT is "A::operator int(&a)" and while
instantiating this CALL_EXPR (in a template) we call finish_call_expr
and that sees a BASELINK and so emits a new dummy object for 'this',
and then we complain about the wrong number of arguments, because now
we basically have two 'this's. Which is exactly the problem I saw
recently in c++/92948.
Yeah, the problem continues to be that build_converted_constant_expr is
breaking the boundary between template and non-template codes:
convert_like_real produces trees that aren't suitable for later
substitution, so substituting them breaks. Perhaps if we're looking at
a non-dependent constant expression in a template,
build_converted_constant_expr should instantiate_non_dependent_expr,
pass the result to convert_like, and then if successful throw away the
result in favor of an IMPLICIT_CONV_EXPR.
Bootstrapped/regtested on x86_64-linux, ok for trunk and 9?
PR c++/91465 - ICE with template codes in check_narrowing.
* typeck2.c (check_narrowing): Call fold_non_dependent_expr
instead of maybe_constant_value.
* g++.dg/cpp0x/pr91465.C: New test.
* g++.dg/cpp1z/pr91465.C: New test.
---
gcc/cp/typeck2.c | 4 +++-
gcc/testsuite/g++.dg/cpp0x/pr91465.C | 16 ++++++++++++++++
gcc/testsuite/g++.dg/cpp1z/pr91465.C | 10 ++++++++++
3 files changed, 29 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/pr91465.C
create mode 100644 gcc/testsuite/g++.dg/cpp1z/pr91465.C
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index 371b203c29b..8f8e9703ac8 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -981,7 +981,9 @@ check_narrowing (tree type, tree init, tsubst_flags_t
complain,
return ok;
}
- init = maybe_constant_value (init);
+ init = fold_non_dependent_expr (init, tf_none);
+ if (init == error_mark_node)
+ return ok;
/* If we were asked to only check constants, return early. */
if (const_only && !TREE_CONSTANT (init))
diff --git a/gcc/testsuite/g++.dg/cpp0x/pr91465.C
b/gcc/testsuite/g++.dg/cpp0x/pr91465.C
new file mode 100644
index 00000000000..e2021aa13e1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/pr91465.C
@@ -0,0 +1,16 @@
+// PR c++/91465 - ICE with template codes in check_narrowing.
+// { dg-do compile { target c++11 } }
+
+enum class D { X };
+enum class S { Z };
+
+D foo(S) { return D{}; }
+D foo(double) { return D{}; }
+
+template <typename>
+struct Bar {
+ D baz(S s)
+ {
+ return D{foo(s)};
+ }
+};
diff --git a/gcc/testsuite/g++.dg/cpp1z/pr91465.C
b/gcc/testsuite/g++.dg/cpp1z/pr91465.C
new file mode 100644
index 00000000000..5b1205349d0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/pr91465.C
@@ -0,0 +1,10 @@
+// PR c++/91465 - ICE with template codes in check_narrowing.
+// { dg-do compile { target c++17 } }
+
+enum class E { Z };
+
+template <typename F>
+void foo(F)
+{
+ E{char(0)};
+}
base-commit: cb273d81a45092ceee793f0357526e291f03c7b7
