[perl #117535, #76910] Fix bogus ambiguity warnings

‘Ambiguous use of * resolved as operator *’: This message can occur in
cases where there is no multiplication operator, so what it is saying
is completely wrong.

When the lexer parses a bareword, it looks at the previous character
and warns if it happens to match /[*%&]/, so foo**bar and foo&&bar
result in this warning, as does print $%foo.

The purpose of the code is to catch *bar *bar or &black &sheep.

To avoid false positives, when emitting one of the three operators
* % & the lexer can record that fact, so when it sees a bareword pre-
ceded by one of those three characters, instead of guessing that the
infix operator was used, it will *know*.

The test cases added also trigger ‘Bareword found where operator
expected’.  I don’t know whether that should change, but at least the
current behaviour is tested, so we will know when it does change.

1 files changed, 7 insertions, 1 deletions

diff --git a/toke.c b/toke.c
index aedccc555d..8f6eb44177 100644
--- a/toke.c
+++ b/toke.c
@@ -4640,6 +4640,7 @@ Perl_yylex(pTHX)
     char *d;
     STRLEN len;
     bool bof = FALSE;
+    const bool saw_infix_sigil = PL_parser->saw_infix_sigil;
     U8 formbrack = 0;
     U32 fake_eof = 0;
 
@@ -5042,6 +5043,7 @@ Perl_yylex(pTHX)
     s = PL_bufptr;
     PL_oldoldbufptr = PL_oldbufptr;
     PL_oldbufptr = s;
+    PL_parser->saw_infix_sigil = 0;
 
   retry:
 #ifdef PERL_MAD
@@ -5697,6 +5699,7 @@ Perl_yylex(pTHX)
 	    s--;
 	    TOKEN(0);
 	}
+	PL_parser->saw_infix_sigil = 1;
 	Mop(OP_MULTIPLY);
 
     case '%':
@@ -5705,6 +5708,7 @@ Perl_yylex(pTHX)
 		    PL_lex_fakeeof >= LEX_FAKEEOF_ASSIGN)
 		TOKEN(0);
 	    ++s;
+	    PL_parser->saw_infix_sigil = 1;
 	    Mop(OP_MODULO);
 	}
 	PL_tokenbuf[0] = '%';
@@ -6198,6 +6202,7 @@ Perl_yylex(pTHX)
 		s--;
 		TOKEN(0);
 	    }
+	    PL_parser->saw_infix_sigil = 1;
 	    BAop(OP_BIT_AND);
 	}
 
@@ -7433,7 +7438,8 @@ Perl_yylex(pTHX)
 		op_free(rv2cv_op);
 
 	    safe_bareword:
-		if ((lastchar == '*' || lastchar == '%' || lastchar == '&')) {
+		if ((lastchar == '*' || lastchar == '%' || lastchar == '&')
+		 && saw_infix_sigil) {
 		    Perl_ck_warner_d(aTHX_ packWARN(WARN_AMBIGUOUS),
 				     "Operator or semicolon missing before %c%"SVf,
 				     lastchar, SVfARG(newSVpvn_flags(PL_tokenbuf,