[PATCH] c++: fix for printing std::meta::info [PR124489]

[Marek Polacek]

Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

-- >8 --
When printing the diagnostics in this test, we're saying
"constexprstd::meta::info dm" which misses a space.  We
should use pp_cxx_ws_string which does pp_c_maybe_whitespace
when printing "std::meta::info".

        PR c++/124489

gcc/cp/ChangeLog:

        * error.cc (dump_type) <case NULLPTR_TYPE>: Use pp_cxx_ws_string
        instead of pp_string.
        <case META_TYPE>: Likewise.

gcc/testsuite/ChangeLog:

        * g++.dg/reflect/diag6.C: New test.
---
 gcc/cp/error.cc                      |  4 ++--
 gcc/testsuite/g++.dg/reflect/diag6.C | 10 ++++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/reflect/diag6.C

diff --git a/gcc/cp/error.cc b/gcc/cp/error.cc
index 25e438c1784..f198a1fe065 100644
--- a/gcc/cp/error.cc
+++ b/gcc/cp/error.cc
@@ -875,11 +875,11 @@ dump_type (cxx_pretty_printer *pp, tree t, int flags)
       break;
 
     case NULLPTR_TYPE:
-      pp_string (pp, "std::nullptr_t");
+      pp_cxx_ws_string (pp, "std::nullptr_t");
       break;
 
     case META_TYPE:
-      pp_string (pp, "std::meta::info");
+      pp_cxx_ws_string (pp, "std::meta::info");
       break;
 
     case SPLICE_SCOPE:
diff --git a/gcc/testsuite/g++.dg/reflect/diag6.C 
b/gcc/testsuite/g++.dg/reflect/diag6.C
new file mode 100644
index 00000000000..61caa082551
--- /dev/null
+++ b/gcc/testsuite/g++.dg/reflect/diag6.C
@@ -0,0 +1,10 @@
+// PR c++/124489
+// { dg-do compile { target c++26 } }
+// { dg-additional-options "-freflection" }
+
+void
+g ()
+{
+  constexpr decltype(^^::) dm = ^^int; // { dg-message ".constexpr 
std::meta::info dm. previously declared here" }
+  constexpr decltype(^^::) dm = ^^int; // { dg-error "redeclaration of 
.constexpr std::meta::info dm." }
+}

base-commit: 64f95a0eeaf1cb6d07cc414c9b2953a494e03be1
-- 
2.53.0