diff --git a/src/Init/Data/List/Basic.lean b/src/Init/Data/List/Basic.lean
index c783c236e0d3..d99b37a6ff92 100644
--- a/src/Init/Data/List/Basic.lean
+++ b/src/Init/Data/List/Basic.lean
@@ -270,7 +270,7 @@ Compares lists lexicographically with respect to a comparison on their elements.
 
 The lexicographic order with respect to `lt` is:
 * `[].lex (b :: bs)` is `true`
-* `as.lex [] = false` is `false`
+* `as.lex []` is `false`
 * `(a :: as).lex (b :: bs)` is true if `lt a b` or `a == b` and `lex lt as bs` is true.
 -/
 @[specialize]