decoder: Add failing test for JSON traversal

decoder/expr_reference_ref_origins_test.go

@@ -279,6 +279,39 @@ func TestCollectRefOrigins_exprReference_json(t *testing.T) {
 				},
 			},
 		},
+		{ // TODO: HCL misreports range for traversals w/ string keys in JSON (off by 2)
+			"traversal with string index steps",
+			map[string]*schema.AttributeSchema{
+				"attr": {
+					Constraint: schema.Reference{
+						OfType: cty.String,
+					},
+					IsOptional: true,
+				},
+			},
+			`{"attr": "${one.two[\"key\"].attr[\"foo\"]}"}`,
+			reference.Origins{
+				reference.LocalOrigin{
+					Addr: lang.Address{
+						lang.RootStep{Name: "one"},
+						lang.AttrStep{Name: "two"},
+						lang.IndexStep{Key: cty.StringVal("key")},
+						lang.AttrStep{Name: "attr"},
+						lang.IndexStep{Key: cty.StringVal("foo")},
+					},
+					Range: hcl.Range{
+						Filename: "test.tf.json",
+						Start:    hcl.Pos{Line: 1, Column: 13, Byte: 12},
+						End:      hcl.Pos{Line: 1, Column: 32, Byte: 31},
+					},
+					Constraints: reference.OriginConstraints{
+						{
+							OfType: cty.String,
+						},
+					},
+				},
+			},
+		},
 	}
 	for i, tc := range testCases {
 		t.Run(fmt.Sprintf("%d-%s", i, tc.testName), func(t *testing.T) {