On 4/21/20 9:55 AM, Patrick Palka wrote:
When building the parameter mapping for an atomic constraint,
find_template_parameters does not spot the template parameter within the
conversion-type-id of a dependent conversion operator, which later leads to an
ICE during substitution when looking up the missing template argument for this
unnoticed template parameter.
(The below testcase is a modification of the reduced testcase in the PR, adding
parens to the requirement 'e.operator c;' as a workaround for PR94645.)
Boostrapped and regtested on x86_64-pc-linux-gnu, does this look OK to commit?
OK.
gcc/cp/ChangeLog:
PR c++/94597
* pt.c (any_template_parm_r) <case IDENTIFIER_NODE>: New case. If this
is a conversion operator, visit its TREE_TYPE.
gcc/testsuite/ChangeLog:
PR c++/94597
* g++.dg/cpp2a/concepts-conv2.C: New test.
---
gcc/cp/pt.c | 6 ++++++
gcc/testsuite/g++.dg/cpp2a/concepts-conv2.C | 19 +++++++++++++++++++
2 files changed, 25 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-conv2.C
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index cd6392aca22..2111f031d9e 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -10529,6 +10529,12 @@ any_template_parm_r (tree t, void *data)
}
break;
+ case IDENTIFIER_NODE:
+ if (IDENTIFIER_CONV_OP_P (t))
+ /* The conversion-type-id of a conversion operator may be dependent. */
+ WALK_SUBTREE (TREE_TYPE (t));
+ break;
+
default:
break;
}
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-conv2.C
b/gcc/testsuite/g++.dg/cpp2a/concepts-conv2.C
new file mode 100644
index 00000000000..abe68187cce
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-conv2.C
@@ -0,0 +1,19 @@
+// PR c++/94597
+// { dg-do compile { target c++2a } }
+
+template <typename b, typename c> concept d = requires(b e) { e.operator c();
};
+
+template <typename f, typename g> requires(d<f, g>) bool equal(f, g);
+
+template <typename h> struct i {
+ i(h);
+ operator h();
+};
+
+static_assert(d<i<float>, float>);
+static_assert(!d<i<float>, int>);
+
+bool fun() {
+ i a(2.0f);
+ return equal(a, 3.0f);
+}
