Fix #537: Invert UI test logic to filter by pass markers instead of error patterns

Author: harin-ramesh

build_system/src/test.rs

@@ -834,52 +834,32 @@ fn valid_ui_error_pattern_test(file: &str) -> bool {
     .any(|to_ignore| file.ends_with(to_ignore))
 }
 
-fn contains_ui_error_patterns(file_path: &Path, keep_lto_tests: bool) -> Result<bool, String> {
-    // Tests generating errors.
+fn contains_ui_error_patterns(file_path: &Path, _keep_lto_tests: bool) -> Result<bool, String> {
+    // Inverted logic: UI tests are expected to fail by default unless marked with pass markers.
+    // Return false (keep) for tests with pass markers, true (remove) for everything else.
     let file = File::open(file_path)
         .map_err(|error| format!("Failed to read `{}`: {:?}", file_path.display(), error))?;
     for line in BufReader::new(file).lines().map_while(Result::ok) {
         let line = line.trim();
         if line.is_empty() {
             continue;
         }
+
+        // Check for pass markers - these tests should be kept (return false)
         if [
-            "//@ error-pattern:",
-            "//@ build-fail",
-            "//@ run-fail",
-            "//@ known-bug",
-            "-Cllvm-args",
-            "//~",
-            "thread",
+            "//@ check-pass",
+            "//@ build-pass",
+            "//@ run-pass",
         ]
         .iter()
-        .any(|check| line.contains(check))
+        .any(|marker| line.contains(marker))
         {
-            return Ok(true);
+            return Ok(false);
         }
-
-        if !keep_lto_tests
-            && (line.contains("-Clto")
-                || line.contains("-C lto")
-                || line.contains("compile-flags: -Clinker-plugin-lto"))
-            && !line.contains("-Clto=thin")
-        {
-            return Ok(true);
-        }
-
-        if line.contains("//[") && line.contains("]~") {
-            return Ok(true);
-        }
-    }
-    let file_path = file_path.display().to_string();
-    if file_path.contains("ambiguous-4-extern.rs") {
-        eprintln!("nothing found for {file_path:?}");
     }
-    // The files in this directory contain errors.
-    if file_path.contains("/error-emitter/") {
-        return Ok(true);
-    }
-    Ok(false)
+
+    // Default: remove tests without pass markers (expected to fail by default)
+    Ok(true)
 }
 
 // # Parameters