diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
index 4e09d23169aca..a65b5dade3e56 100644
--- a/compiler/rustc_metadata/src/rmeta/mod.rs
+++ b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -48,7 +48,7 @@ crate fn rustc_version() -> String {
 /// Metadata encoding version.
 /// N.B., increment this if you change the format of metadata such that
 /// the rustc version can't be found to compare with `rustc_version()`.
-const METADATA_VERSION: u8 = 5;
+const METADATA_VERSION: u8 = 6;
 
 /// Metadata header which includes `METADATA_VERSION`.
 ///