code review 4442099: gc: preserve original expression for errors

src/cmd/gc/subr.c

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 #include        "go.h"
 #include        "md5.h"
 #include        "y.tab.h"
 #include        "opnames.h"
 #include        "yerr.h"
 
@@ skipping 1436 matching lines @@
                 if(n->type == T)
                         fmtprint(fp, "%#N", n);
                 else if(n->type->etype == TNIL)
                         fmtprint(fp, "nil");
                 else
                         fmtprint(fp, "%#N (type %T)", n, n->type);
                 goto out;
         }
 
         if(fp->flags & FmtSharp) {
+                if(n->orig != N)
+                        n = n->orig;
                 exprfmt(fp, n, 0);
                 goto out;
         }
 
         switch(n->op) {
         default:
                 fmtprint(fp, "%O%J", n->op, n);
                 break;
 
         case ONAME:
@@ skipping 2257 matching lines @@
 Strlit*
 strlit(char *s)
 {
         Strlit *t;
 ········
         t = mal(sizeof *t + strlen(s));
         strcpy(t->s, s);
         t->len = strlen(s);
         return t;
 }