fix: implication operator (->)

nix-js/src/codegen.rs

@@ -351,7 +351,7 @@ impl<Ctx: CodegenContext> Compile<Ctx> for BinOp {
             Impl => {
                 code!(
                     buf, ctx;
-                    "Nix.withContext(\"while evaluating the || operator\"," self.span ",()=>(Nix.forceBool(" lhs ")||Nix.forceBool(" rhs ")))"
+                    "Nix.withContext(\"while evaluating the -> operator\"," self.span ",()=>(!Nix.forceBool(" lhs ")||Nix.forceBool(" rhs ")))"
                 );
             }
             PipeL => {

nix-js/tests/operators.rs

@@ -117,3 +117,28 @@ fn select_with_default_nested_lazy() {
 fn select_with_default_fallback() {
     assert_eq!(eval("{ a = 1; }.b or 999"), Value::Int(999));
 }
+
+#[test]
+fn implication_false_false() {
+    assert_eq!(eval("false -> false"), Value::Bool(true));
+}
+
+#[test]
+fn implication_false_true() {
+    assert_eq!(eval("false -> true"), Value::Bool(true));
+}
+
+#[test]
+fn implication_true_false() {
+    assert_eq!(eval("true -> false"), Value::Bool(false));
+}
+
+#[test]
+fn implication_true_true() {
+    assert_eq!(eval("true -> true"), Value::Bool(true));
+}
+
+#[test]
+fn implication_short_circuit() {
+    assert_eq!(eval("false -> (1 / 0)"), Value::Bool(true));
+}