Revert accidentally applied patch for 6.c version of Grammar

src/core.c/Grammar.pm6

@@ -1,62 +1,5 @@
 my class Grammar is Match {
 
-    # (oughta be down in Match or even nqp really)
-    method locprepost() {
-        my $orig = self.orig;
-        my $marked = self.?MARKED('ws');
-        my $pos = $marked && index(" }])>»", substr($orig, self.pos, 1)) < 0 ?? $marked.from !! self.pos;
-
-        my $prestart = $pos - 40;
-        $prestart = 0 if $prestart < 0;
-        my $pre = substr($orig, $prestart, $pos - $prestart);
-        $pre = $pre.subst(/.*\n/, "");
-        $pre = '<BOL>' if $pre eq '';
-
-        my $postchars = $pos + 40 > chars($orig) ?? chars($orig) - $pos !! 40;
-        my $post = substr($orig, $pos, $postchars);
-        $post = $post.subst(/\n.*/, "");
-        $post = '<EOL>' if $post eq '';
-
-        [$pre, $post]
-    }
-
-    # stolen and trimmed down from World
-    method typed_exception(X::Comp $ex, *%opts) {
-        # If the highwater is beyond the current position, force the cursor to that location.
-        my @expected;
-        my $high = self.'!highwater'();
-
-        if $high >= self.pos() {
-            self.'!cursor_pos'($high);
-            my $highexpect := self.'!highexpect'();
-            if nqp::islist($highexpect) {
-                my %seen;
-                for ^nqp::elems($highexpect) {
-                    my $x = nqp::hllizefor(nqp::shift($highexpect),'perl6');
-                    push @expected, $x unless %seen{$x}++;
-                }
-                @expected .= sort;
-            }
-        }
-
-        my @locprepost := self.locprepost();
-        # Build and throw exception object.
-        %opts<line>            = HLL::Compiler.lineof(self.orig, self.pos, :cache(1));
-        # only set <pos> if it's not already set:
-        %opts<pos>             //= self.pos;
-        %opts<pre>             = @locprepost[0];
-        %opts<post>            = @locprepost[1];
-        %opts<highexpect>      = @expected if @expected;
-        %opts<is-compile-time> = 1;
-        Failure.new($ex.new(|%opts))
-    }
-
-    method SETFAIL($failed, :$filename) {
-        return Nil unless self.defined && nqp::isge_s(CLIENT::LEXICAL::<CORE-SETTING-REV>, 'e');
-        self.'!cursor_pos'($failed.pos);
-        self.typed_exception(X::Syntax::Confused, filename => ($filename // "<anon>"))
-    }
-
     method parse(\target, :$rule, :$args, Mu :$actions, :$filename) is raw {
         my $*LINEPOSCACHE;
         nqp::stmts(
@@ -85,9 +28,9 @@ my class Grammar is Match {
                   ),
                   $match := ($cursor := $cursor.'!cursor_next'()).MATCH
                 ),
-                $match || $grammar.SETFAIL($match, :$filename),
+                $match || Nil,
               ),
-              $grammar.SETFAIL($cursor, :$filename),
+              Nil,
             )
           )
         )