new lint: bool_simplification

TODO: add more patterns to this

3 files changed, 22 insertions, 1 deletions

diff --git a/bin/tests/data/bool_simplification.nix b/bin/tests/data/bool_simplification.nix
new file mode 100644
index 0000000..64c2c7a
--- /dev/null
+++ b/bin/tests/data/bool_simplification.nix
@@ -0,0 +1,7 @@
+let
+  _ = !(a == b);
+  # do not match here
+  _ = !(a != b);
+  _ = a != b;
+in
+  null
diff --git a/bin/tests/main.rs b/bin/tests/main.rs
index bec64d2..3403f65 100644
--- a/bin/tests/main.rs
+++ b/bin/tests/main.rs
@@ -63,5 +63,6 @@ test_lint! {
     empty_inherit,
     faster_groupby => session_info!("2.5"),
     faster_zipattrswith => session_info!("2.6"),
-    deprecated_to_path => session_info!("2.4")
+    deprecated_to_path => session_info!("2.4"),
+    bool_simplification
 }
diff --git a/bin/tests/snapshots/main__bool_simplification.snap b/bin/tests/snapshots/main__bool_simplification.snap
new file mode 100644
index 0000000..9e3c991
--- /dev/null
+++ b/bin/tests/snapshots/main__bool_simplification.snap
@@ -0,0 +1,13 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W18] Warning: This boolean expression can be simplified
+   ╭─[data/bool_simplification.nix:2:7]
+   │
+ 2 │   _ = !(a == b);
+   ·       ────┬────  
+   ·           ╰────── Try != instead of !(... == ...)
+───╯
+