[gcc r12-8173] c++: unsigned int32_t enum promotion [PR102804]

[gcc r12-8173] c++: unsigned int32_t enum promotion [PR102804]

[Jason Merrill]

https://gcc.gnu.org/g:e580f81d22d61153564959f08d9a6d3bcc7fd386

commit r12-8173-ge580f81d22d61153564959f08d9a6d3bcc7fd386
Author: Jason Merrill <jason@redhat.com>
Date:   Thu Apr 14 17:49:47 2022 -0400

    c++: unsigned int32_t enum promotion [PR102804]
    
    There's been an extension for a long time to allow applying 'unsigned' to an
    int typedef, but that was confusing the integer promotion code.  Fixed by
    forgetting about the typedef in that case.
    
    I'm going to make this an unconditional pedwarn in stage 1.
    
            PR c++/102804
    
    gcc/cp/ChangeLog:
    
            * decl.cc (grokdeclarator): Drop typedef used with 'unsigned'.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/ext/unsigned-typedef1.C: New test.

Diff:
---
 gcc/cp/decl.cc                               | 2 ++
 gcc/testsuite/g++.dg/ext/unsigned-typedef1.C | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index d51fd75b003..2852093d624 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -12243,6 +12243,8 @@ grokdeclarator (const cp_declarator *declarator,
 	      pedwarn (loc, OPT_Wpedantic, "%qs specified with %qT",
 		       key, type);
 	      ok = !flag_pedantic_errors;
+	      type = DECL_ORIGINAL_TYPE (typedef_decl);
+	      typedef_decl = NULL_TREE;
 	    }
 	  else if (declspecs->decltype_p)
 	    error_at (loc, "%qs specified with %<decltype%>", key);
diff --git a/gcc/testsuite/g++.dg/ext/unsigned-typedef1.C b/gcc/testsuite/g++.dg/ext/unsigned-typedef1.C
new file mode 100644
index 00000000000..360b5f81edf
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/unsigned-typedef1.C
@@ -0,0 +1,9 @@
+// PR c++/102804
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wpedantic" }
+
+using int32_t = int;
+enum: unsigned int32_t { foo };	// { dg-warning "int32_t" }
+int f(int) = delete;
+int f(unsigned);
+auto x = f(1 ? foo : 1);