Add support to pat_lit to fold.

Author: graydon

src/comp/middle/fold.rs

@@ -160,6 +160,9 @@ type ast_fold[ENV] =
      (fn(&ENV e, &span sp,
          ann a) -> @pat)                          fold_pat_wild,
 
+     (fn(&ENV e, &span sp,
+         @ast.lit lit, ann a) -> @pat)            fold_pat_lit,
+
      (fn(&ENV e, &span sp,
          ident i, def_id did, ann a) -> @pat)     fold_pat_bind,
 
@@ -421,6 +424,9 @@ fn fold_pat[ENV](&ENV env, ast_fold[ENV] fld, @ast.pat p) -> @ast.pat {
 
     alt (p.node) {
         case (ast.pat_wild(?t)) { ret fld.fold_pat_wild(env_, p.span, t); }
+        case (ast.pat_lit(?lt, ?t)) {
+            ret fld.fold_pat_lit(env_, p.span, lt, t);
+        }
         case (ast.pat_bind(?id, ?did, ?t)) {
             ret fld.fold_pat_bind(env_, p.span, id, did, t);
         }
@@ -1122,6 +1128,10 @@ fn identity_fold_pat_wild[ENV](&ENV e, &span sp, ann a) -> @pat {
     ret @respan(sp, ast.pat_wild(a));
 }
 
+fn identity_fold_pat_lit[ENV](&ENV e, &span sp, @ast.lit lit, ann a) -> @pat {
+    ret @respan(sp, ast.pat_lit(lit, a));
+}
+
 fn identity_fold_pat_bind[ENV](&ENV e, &span sp, ident i, def_id did, ann a)
         -> @pat {
     ret @respan(sp, ast.pat_bind(i, did, a));
@@ -1373,6 +1383,7 @@ fn new_identity_fold[ENV]() -> ast_fold[ENV] {
          fold_decl_item   = bind identity_fold_decl_item[ENV](_,_,_),
 
          fold_pat_wild    = bind identity_fold_pat_wild[ENV](_,_,_),
+         fold_pat_lit     = bind identity_fold_pat_lit[ENV](_,_,_,_),
          fold_pat_bind    = bind identity_fold_pat_bind[ENV](_,_,_,_,_),
          fold_pat_tag     = bind identity_fold_pat_tag[ENV](_,_,_,_,_,_),