From e332a6b3be1e6775603103f326d96ce970eb8229 Mon Sep 17 00:00:00 2001
From: Nicholas Wiersma <nick@wiersma.co.za>
Date: Thu, 27 Aug 2020 11:52:04 +0200
Subject: [PATCH] fix: check array size symbol kind

When determining the size of an array and a symbol is found, the symbol must be a const for the type to be valid.

While it makes sense for this check to be done in type checking, the type can be determined by GTA which would then fail. For now this check is done when getting the node type.

Fixes #825
---
 interp/interp_eval_test.go | 3 +++
 interp/type.go             | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/interp/interp_eval_test.go b/interp/interp_eval_test.go
index c68fde24..beb75076 100644
--- a/interp/interp_eval_test.go
+++ b/interp/interp_eval_test.go
@@ -326,6 +326,7 @@ func TestEvalComparison(t *testing.T) {
 
 func TestEvalCompositeArray(t *testing.T) {
 	i := interp.New(interp.Options{})
+	eval(t, i, `const l = 10`)
 	runTests(t, i, []testCase{
 		{src: "a := []int{1, 2, 7: 20, 30}", res: "[1 2 0 0 0 0 0 20 30]"},
 		{src: `a := []int{1, 1.2}`, err: "1:42: 6/5 truncated to int"},
@@ -333,6 +334,8 @@ func TestEvalCompositeArray(t *testing.T) {
 		{src: `a := []int{1.1:1, 1.2:"test"}`, err: "1:39: index float64 must be integer constant"},
 		{src: `a := [2]int{1, 1.2}`, err: "1:43: 6/5 truncated to int"},
 		{src: `a := [1]int{1, 2}`, err: "1:43: index 1 is out of bounds (>= 1)"},
+		{src: `b := [l]int{1, 2}`, res: "[1 2 0 0 0 0 0 0 0 0]"},
+		{src: `i := 10; a := [i]int{1, 2}`, err: "1:43: non-constant array bound \"i\""},
 	})
 }
 
diff --git a/interp/type.go b/interp/type.go
index dba9cef5..5a2b4a98 100644
--- a/interp/type.go
+++ b/interp/type.go
@@ -182,6 +182,9 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 				t.size = arrayTypeLen(n.anc)
 			default:
 				if sym, _, ok := sc.lookup(n.child[0].ident); ok {
+					if sym.kind != constSym {
+						return nil, n.child[0].cfgErrorf("non-constant array bound %q", n.child[0].ident)
+					}
 					// Resolve symbol to get size value
 					if sym.typ != nil && sym.typ.cat == intT {
 						if v, ok := sym.rval.Interface().(int); ok {