[PATCH] c++: Don't show constructor internal name in error message [PR105483]

[Simon Martin]

We mention 'X::__ct' instead of 'X::X' in the "names the constructor,
not the type" error for this invalid code:

=== cut here ===
struct X {};
void g () {
  X::X x;
}
=== cut here ===

The problem is that we use %<%T::%D%> to build the error message, while
%qE does exactly what we need since we have DECL_CONSTRUCTOR_P. This is
what this patch does, along with skipping until the end of the statement
to avoid emitting extra (useless) errors.

Successfully tested on x86_64-pc-linux-gnu.

        PR c++/105483

gcc/cp/ChangeLog:

        * parser.cc (cp_parser_expression_statement): Use %qE instead of
        incorrect %<%T::%D%>, and skip to end of statement.

gcc/testsuite/ChangeLog:

        * g++.dg/tc1/dr147.C: Adjust test expectation.
        * g++.dg/diagnostic/pr105483.C: New test.

---
 gcc/cp/parser.cc                           | 7 ++++---
 gcc/testsuite/g++.dg/diagnostic/pr105483.C | 7 +++++++
 gcc/testsuite/g++.dg/tc1/dr147.C           | 2 +-
 3 files changed, 12 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/diagnostic/pr105483.C

diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 28ebf2beb60..ef4e3838a86 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -13240,10 +13240,11 @@ cp_parser_expression_statement (cp_parser* parser, 
tree in_statement_expr)
               && DECL_CONSTRUCTOR_P (get_first_fn (statement)))
        {
          /* A::A a; */
-         tree fn = get_first_fn (statement);
          error_at (token->location,
-                   "%<%T::%D%> names the constructor, not the type",
-                   DECL_CONTEXT (fn), DECL_NAME (fn));
+                   "%qE names the constructor, not the type",
+                   get_first_fn (statement));
+         cp_parser_skip_to_end_of_block_or_statement (parser);
+         return error_mark_node;
        }
     }
 
diff --git a/gcc/testsuite/g++.dg/diagnostic/pr105483.C 
b/gcc/testsuite/g++.dg/diagnostic/pr105483.C
new file mode 100644
index 00000000000..b935bacea11
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/pr105483.C
@@ -0,0 +1,7 @@
+// PR c++/105483
+// { dg-do compile }
+
+struct X { };
+void g () {
+  X::X x; // { dg-error "'X::X' names the constructor" }
+}
diff --git a/gcc/testsuite/g++.dg/tc1/dr147.C b/gcc/testsuite/g++.dg/tc1/dr147.C
index 6b656491e81..ced18d1879c 100644
--- a/gcc/testsuite/g++.dg/tc1/dr147.C
+++ b/gcc/testsuite/g++.dg/tc1/dr147.C
@@ -21,7 +21,7 @@ void A::f()
 void f()
 {
   A::A a; // { dg-error "constructor" "constructor" }
-} // { dg-error "" "error cascade" { target *-*-* } .-1 } error cascade
+}
 }
 
 namespace N2 {
-- 
2.44.0