Include negative index of array in warnings about an unitialized value wen constant...

When constant folding isn't done OP_NEGATE isn't merged with
a constant, and the index isn't detected when warning about
unintialized values. This patch adds special handling for OP_NEGATE to
the index detection.

diff --git a/sv.c b/sv.c
index ea78558..f555e44 100644 (file)
--- a/sv.c
+++ b/sv.c
@@ -13909,6 +13909,9 @@ S_find_uninit_var(pTHX_ const OP *const obase, const SV *const uninit_sv,
 
     case OP_AELEM:
     case OP_HELEM:
+    {
+       bool negate = FALSE;
+
        if (PL_op == obase)
            /* $a[uninit_expr] or $h{uninit_expr} */
            return find_uninit_var(cBINOPx(obase)->op_last, uninit_sv, match);
@@ -13934,28 +13937,43 @@ S_find_uninit_var(pTHX_ const OP *const obase, const SV *const uninit_sv,
        if (!sv)
            break;
 
+       if (kid && kid->op_type == OP_NEGATE) {
+           negate = TRUE;
+           kid = cUNOPx(kid)->op_first;
+       }
+
        if (kid && kid->op_type == OP_CONST && SvOK(cSVOPx_sv(kid))) {
            /* index is constant */
+           SV* kidsv;
+           if (negate) {
+               kidsv = sv_2mortal(newSVpvs("-"));
+               sv_catsv(kidsv, cSVOPx_sv(kid));
+           }
+           else
+               kidsv = cSVOPx_sv(kid);
            if (match) {
                if (SvMAGICAL(sv))
                    break;
                if (obase->op_type == OP_HELEM) {
-                   HE* he = hv_fetch_ent(MUTABLE_HV(sv), cSVOPx_sv(kid), 0, 0);
+                   HE* he = hv_fetch_ent(MUTABLE_HV(sv), kidsv, 0, 0);
                    if (!he || HeVAL(he) != uninit_sv)
                        break;
                }
                else {
-                   SV * const * const svp = av_fetch(MUTABLE_AV(sv), SvIV(cSVOPx_sv(kid)), FALSE);
+                   SV * const * const svp = av_fetch(MUTABLE_AV(sv),
+                       negate ? - SvIV(cSVOPx_sv(kid)) : SvIV(cSVOPx_sv(kid)),
+                       FALSE);
                    if (!svp || *svp != uninit_sv)
                        break;
                }
            }
            if (obase->op_type == OP_HELEM)
                return varname(gv, '%', o->op_targ,
-                           cSVOPx_sv(kid), 0, FUV_SUBSCRIPT_HASH);
+                           kidsv, 0, FUV_SUBSCRIPT_HASH);
            else
                return varname(gv, '@', o->op_targ, NULL,
-                           SvIV(cSVOPx_sv(kid)), FUV_SUBSCRIPT_ARRAY);
+                   negate ? - SvIV(cSVOPx_sv(kid)) : SvIV(cSVOPx_sv(kid)),
+                   FUV_SUBSCRIPT_ARRAY);
        }
        else  {
            /* index is an expression;
@@ -13981,6 +13999,7 @@ S_find_uninit_var(pTHX_ const OP *const obase, const SV *const uninit_sv,
                o->op_targ, NULL, 0, FUV_SUBSCRIPT_WITHIN);
        }
        break;
+    }
 
     case OP_AASSIGN:
        /* only examine RHS */