diff --git a/src/librustc/mir/interpret/mod.rs b/src/librustc/mir/interpret/mod.rs
index 65f4c9c47d0a..1ec95c29a4a6 100644
--- a/src/librustc/mir/interpret/mod.rs
+++ b/src/librustc/mir/interpret/mod.rs
@@ -9,6 +9,11 @@ macro_rules! err_unsup {
     };
 }
 
+#[macro_export]
+macro_rules! err_unsup_format {
+    ($($tt:tt)*) => { err_unsup!(Unsupported(format!($($tt)*))) };
+}
+
 #[macro_export]
 macro_rules! err_inval {
     ($($tt:tt)*) => {
@@ -27,6 +32,11 @@ macro_rules! err_ub {
     };
 }
 
+#[macro_export]
+macro_rules! err_ub_format {
+    ($($tt:tt)*) => { err_ub!(Ub(format!($($tt)*))) };
+}
+
 #[macro_export]
 macro_rules! err_panic {
     ($($tt:tt)*) => {