diff --git a/Cargo.toml b/Cargo.toml
index af1aedec06..da1b0626a9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -38,7 +38,6 @@ undocumented_unsafe_blocks = "warn"
 redundant_else = "warn"
 match_same_arms = "warn"
 semicolon_if_nothing_returned = "warn"
-map_flatten = "warn"
 
 ptr_as_ptr = "warn"
 ptr_cast_constness = "warn"