diff --git a/helper/schema/schema.go b/helper/schema/schema.go
index ed8b0ac94a4e..4674eb17661d 100644
--- a/helper/schema/schema.go
+++ b/helper/schema/schema.go
@@ -17,7 +17,6 @@ import (
 	"reflect"
 	"sort"
 	"strconv"
-	"strings"
 
 	"github.com/hashicorp/terraform/terraform"
 	"github.com/mitchellh/mapstructure"
@@ -817,7 +816,11 @@ func (m schemaMap) diffSet(
 			// This is a complex resource
 			for k2, schema := range t.Schema {
 				subK := fmt.Sprintf("%s.%d.%s", k, code, k2)
-				subK = strings.Replace(subK, "-", "~", -1)
+				// Replace a negative hashcode (computed) with a tilde. The
+				// tilde is used as a marker when diffing computed keys.
+				if code < 0 {
+					subK = fmt.Sprintf("%s.~%d.%s", k, -code, k2)
+				}
 				err := m.diff(subK, schema, diff, d, true)
 				if err != nil {
 					return err
@@ -832,7 +835,11 @@ func (m schemaMap) diffSet(
 			// This is just a primitive element, so go through each and
 			// just diff each.
 			subK := fmt.Sprintf("%s.%d", k, code)
-			subK = strings.Replace(subK, "-", "~", -1)
+			// Replace a negative hashcode (computed) with a tilde. The
+			// tilde is used as a marker when diffing computed keys.
+			if code < 0 {
+				subK = fmt.Sprintf("%s.~%d", k, -code)
+			}
 			err := m.diff(subK, &t2, diff, d, true)
 			if err != nil {
 				return err
diff --git a/helper/schema/schema_test.go b/helper/schema/schema_test.go
index 52980ad80afd..12e543c20a6a 100644
--- a/helper/schema/schema_test.go
+++ b/helper/schema/schema_test.go
@@ -1675,6 +1675,11 @@ func TestSchemaMap_Diff(t *testing.T) {
 								Type:     TypeString,
 								Optional: true,
 							},
+
+							"foo-bar": &Schema{
+								Type:     TypeString,
+								Optional: true,
+							},
 						},
 					},
 					Set: func(v interface{}) int {
@@ -1691,6 +1696,7 @@ func TestSchemaMap_Diff(t *testing.T) {
 					map[string]interface{}{
 						"index":   "1",
 						"gateway": "${var.foo}",
+						"foo-bar": "baz",
 					},
 				},
 			},
@@ -1713,6 +1719,10 @@ func TestSchemaMap_Diff(t *testing.T) {
 						Old: "",
 						New: "${var.foo}",
 					},
+					"route.~1.foo-bar": &terraform.ResourceAttrDiff{
+						Old: "",
+						New: "baz",
+					},
 				},
 			},