PATCH: [perl #128734] tr/\N{...}/ failing for 128-255

The upper latin1 characters when expressed as \N{U+...} were failing.
This was due to trying to convert them to UTF-8 when the result isn't
UTF-8.  I added a test for \N{name} as well, though these were not
affected by this regression.

Author: khwilliamson

t/op/tr.t

@@ -13,7 +13,7 @@ BEGIN {
 
 use utf8;
 
-plan tests => 164;
+plan tests => 166;
 
 # Test this first before we extend the stack with other operations.
 # This caused an asan failure due to a bad write past the end of the stack.
@@ -647,4 +647,13 @@ for ("", nullrocow) {
 	ok(1, "tr///d on glob does not assert");
 }
 
+{ # [perl #128734
+    my $string = "\x{00e0}";
+    $string =~ tr/\N{U+00e0}/A/;
+    is($string, "A", 'tr// of \N{U+...} works for upper-Latin1');
+    $string = "\x{00e1}";
+    $string =~ tr/\N{LATIN SMALL LETTER A WITH ACUTE}/A/;
+    is($string, "A", 'tr// of \N{name} works for upper-Latin1');
+}
+
 1;

toke.c

@@ -3534,7 +3534,7 @@ S_scan_const(pTHX_ char *start)
 			}
 
                         /* Add the (Unicode) code point to the output. */
-			if (OFFUNI_IS_INVARIANT(uv)) {
+			if (! has_utf8 || OFFUNI_IS_INVARIANT(uv)) {
 			    *d++ = (char) LATIN1_TO_NATIVE(uv);
 			}
 			else {