From 74ccfea8f6f704c819a641a30ce5ddc8f83f11b4 Mon Sep 17 00:00:00 2001
From: Tristan Swadell <tswadell@google.com>
Date: Tue, 24 Mar 2020 22:52:02 -0700
Subject: [PATCH] Fix for index attribute resolution via a function call return
 (#325)

---
 interpreter/interpreter_test.go | 3 ++-
 interpreter/planner.go          | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/interpreter/interpreter_test.go b/interpreter/interpreter_test.go
index bfbf4b42..52d24da8 100644
--- a/interpreter/interpreter_test.go
+++ b/interpreter/interpreter_test.go
@@ -217,7 +217,7 @@ var (
 		},
 		{
 			name: "index",
-			expr: `m['key'][1] == 42u && m['null'] == null`,
+			expr: `m['key'][1] == 42u && m['null'] == null && m[string(0)] == 10`,
 			env: []*exprpb.Decl{
 				decls.NewIdent("m", decls.NewMapType(decls.String, decls.Dyn), nil),
 			},
@@ -225,6 +225,7 @@ var (
 				"m": map[string]interface{}{
 					"key":  []uint{21, 42},
 					"null": nil,
+					"0":    10,
 				},
 			},
 		},
diff --git a/interpreter/planner.go b/interpreter/planner.go
index 7e80ac80..1af001a2 100644
--- a/interpreter/planner.go
+++ b/interpreter/planner.go
@@ -501,7 +501,7 @@ func (p *planner) planCallIndex(expr *exprpb.Expr,
 	if isIndAttr {
 		return opAttr.AddQualifier(indAttr.Attr())
 	}
-	return nil, fmt.Errorf("unsupported index expression: %v", expr)
+	return opAttr.AddQualifier(p.attrFactory.RelativeAttribute(ind.ID(), ind))
 }
 
 // planCreateList generates a list construction Interpretable.