[perl #46947] Parse method-BLOCK arguments as a term

(C.f. bug #114222 and commit 52d0e95, which did the same thing
for ‘use’.)

When parsing the arguments following a method name and a block (for
‘method { $obj } LIST‘ syntax), the lexer was using heuristics to
determine whether an opening brace was a hash constructor or a block,
as it does at the beginning of a statement.  In every case in which it
determined it was a block, the parser would them throw a syntax error.

In this case, the lexer should not be trying to guess, since we *know*
it can only be a hash here.

This was the result:

$ perl -e 'method {$obj} {$foo=>undef}'
syntax error at -e line 1, near "} {"
Execution of -e aborted due to compilation errors.

Now we get this:

$ ./miniperl -e 'method {$obj} {$foo=>undef}'
Can't call method "method" on an undefined value at -e line 1.

as expected.

perl.h

@@ -4797,6 +4797,7 @@ typedef enum {
     XATTRBLOCK,
     XATTRTERM,
     XTERMBLOCK,
+    XBLOCKTERM,
     XPOSTDEREF,
     XTERMORDORDOR /* evil hack */
     /* update exp_name[] in toke.c if adding to this enum */

t/comp/parser.t

@@ -8,7 +8,7 @@ BEGIN {
     chdir 't';
 }
 
-print "1..169\n";
+print "1..170\n";
 
 sub failed {
     my ($got, $expected, $name) = @_;
@@ -499,6 +499,10 @@ eval 'for my a1b $i (1) {}';
 # ng: 'Missing $ on loop variable'
 like $@, "^No such class a1b at ", 'TYPE of my of for statement';
 
+eval 'method {} {$_,undef}';
+like $@, qq/^Can't call method "method" on unblessed reference at /,
+     'method BLOCK {...} does not try to disambiguate';
+
 # Add new tests HERE (above this line)
 
 # bug #74022: Loop on characters in \p{OtherIDContinue}

toke.c

@@ -5449,6 +5449,11 @@ Perl_yylex(pTHX)
 	    PL_lex_allbrackets++;
 	    PL_expect = XSTATE;
 	    break;
+	case XBLOCKTERM:
+	    PL_lex_brackstack[PL_lex_brackets++] = XTERM;
+	    PL_lex_allbrackets++;
+	    PL_expect = XSTATE;
+	    break;
 	default: {
 		const char *t;
 		if (PL_oldoldbufptr == PL_last_lop)
@@ -6634,7 +6639,9 @@ Perl_yylex(pTHX)
 		    if (!PL_lex_allbrackets &&
 			    PL_lex_fakeeof > LEX_FAKEEOF_LOWLOGIC)
 			PL_lex_fakeeof = LEX_FAKEEOF_LOWLOGIC;
-		    PREBLOCK(METHOD);
+		    PL_expect = XBLOCKTERM;
+		    PL_bufptr = s;
+		    return REPORT(METHOD);
 		}
 
 		/* If followed by a bareword, see if it looks like indir obj. */