diff --git a/instrumenter.go b/instrumenter.go
index 1a16cff..a52267b 100644
--- a/instrumenter.go
+++ b/instrumenter.go
@@ -522,7 +522,7 @@ func needsParenthesesForEql(expr ast.Expr) bool {
 		*ast.ArrayType,
 		*ast.StructType,
 		*ast.FuncType,
-		// TODO: *ast.InterfaceType,
+		*ast.InterfaceType,
 		*ast.MapType,
 		*ast.ChanType:
 		return false
diff --git a/testdata/instrumenter/TypeSwitchStmt.gobco b/testdata/instrumenter/TypeSwitchStmt.gobco
index bf9f20d..8c475ee 100644
--- a/testdata/instrumenter/TypeSwitchStmt.gobco
+++ b/testdata/instrumenter/TypeSwitchStmt.gobco
@@ -252,7 +252,7 @@ func typeSwitchStmtMixed(value interface{}) {
 // :95:7: "value.(type) == []int"
 // :98:7: "value.(type) == struct{ field int }"
 // :101:7: "value.(type) == func(int) int"
-// :104:7: "value.(type) == (interface{ ReadByte() (byte, error) })"
+// :104:7: "value.(type) == interface{ ReadByte() (byte, error) }"
 // :107:7: "value.(type) == map[int]int"
 // :110:7: "value.(type) == chan int"
 // :113:7: "value.(type) == *int"