diff --git a/clippy_lints/src/booleans.rs b/clippy_lints/src/booleans.rs
index e11f83f2260..2d0af1017d5 100644
--- a/clippy_lints/src/booleans.rs
+++ b/clippy_lints/src/booleans.rs
@@ -502,6 +502,8 @@ impl<'a, 'tcx> Visitor<'tcx> for NotSimplificationVisitor<'a, 'tcx> {
             && !inner.span.from_expansion()
             && let Some(suggestion) = simplify_not(self.cx, inner)
             && self.cx.tcx.lint_level_at_node(NONMINIMAL_BOOL, expr.hir_id).0 != Level::Allow
+            && let Some(snippet) = snippet_opt(self.cx, expr.span)
+            && !snippet.contains("assert")
         {
             span_lint_and_sugg(
                 self.cx,