Test that cfg-gated if-exprs are not type-checked

Author: Aaron1011

src/test/ui/if-attrs/cfg-false-if-attr.rs

@@ -19,6 +19,18 @@ fn if_let() {
     #[attr] if let Some(_) = Some(true) {}
 }
 
+fn bar() {
+    #[cfg(FALSE)]
+    if true {
+        let x: () = true; // Should not error due to the #[cfg(FALSE)]
+    }
+
+    #[cfg_attr(not(unset_attr), cfg(FALSE))]
+    if true {
+        let a: () = true; // Should not error due to the applied #[cfg(FALSE)]
+    }
+}
+
 macro_rules! custom_macro {
     ($expr:expr) => {}
 }