interp: handle aliased string used as a slice

Fixes #1002.
traefik · Jan 14, 2021 · 8ad14d8 · 8ad14d8
1 parent 8a1f9ef
commit 8ad14d8
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Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/interp/cfg.go b/interp/cfg.go
@@ -740,7 +740,13 @@ func (interp *Interpreter) cfg(root *node, importPath string) ([]*node, error) {
 			wireChild(n)
 			t := n.child[0].typ
 			switch t.cat {
-			case aliasT, ptrT:
+			case aliasT:
+				if isString(t.val.TypeOf()) {
+					n.typ = sc.getType("byte")
+					break
+				}
+				fallthrough
+			case ptrT:
 				n.typ = t.val
 				if t.val.cat == valueT {
 					n.typ = &itype{cat: valueT, rtype: t.val.rtype.Elem()}

diff --git a/interp/interp_eval_test.go b/interp/interp_eval_test.go
@@ -457,6 +457,7 @@ func TestEvalSliceExpression(t *testing.T) {
 		{src: `a := []int{0,1,2,3}[1::4]`, err: "1:49: 2nd index required in 3-index slice"},
 		{src: `a := []int{0,1,2,3}[1:3:]`, err: "1:51: 3rd index required in 3-index slice"},
 		{src: `a := []int{0,1,2}[3:1]`, err: "invalid index values, must be low <= high <= max"},
+		{pre: func() { eval(t, i, `type Str = string; var r Str = "truc"`) }, src: `r[1]`, res: "114"},
 	})
 }