Auto merge of rust-lang#85786 - GuillaumeGomez:error-code-checker-improvement, r=Mark-Simulacrum

Error code checker improvement

Just realized that some error codes shouldn't be ignored anymore. So I updated the script to ensure that if an error code is tested and ignored, it will trigger an error.

Author: bors

src/tools/tidy/src/error_codes_check.rs

@@ -8,15 +8,14 @@ use std::path::Path;
 
 // A few of those error codes can't be tested but all the others can and *should* be tested!
 const EXEMPTED_FROM_TEST: &[&str] = &[
-    "E0183", "E0227", "E0279", "E0280", "E0311", "E0313", "E0314", "E0315", "E0377", "E0461",
-    "E0462", "E0464", "E0465", "E0472", "E0473", "E0474", "E0475", "E0476", "E0479", "E0480",
-    "E0481", "E0482", "E0483", "E0484", "E0485", "E0486", "E0487", "E0488", "E0489", "E0514",
-    "E0519", "E0523", "E0553", "E0554", "E0570", "E0629", "E0630", "E0640", "E0717", "E0727",
-    "E0729",
+    "E0227", "E0279", "E0280", "E0313", "E0314", "E0315", "E0377", "E0461", "E0462", "E0464",
+    "E0465", "E0473", "E0474", "E0475", "E0476", "E0479", "E0480", "E0481", "E0482", "E0483",
+    "E0484", "E0485", "E0486", "E0487", "E0488", "E0489", "E0514", "E0519", "E0523", "E0553",
+    "E0554", "E0570", "E0629", "E0630", "E0640", "E0717", "E0729",
 ];
 
 // Some error codes don't have any tests apparently...
-const IGNORE_EXPLANATION_CHECK: &[&str] = &["E0570", "E0601", "E0602", "E0639", "E0729"];
+const IGNORE_EXPLANATION_CHECK: &[&str] = &["E0570", "E0601", "E0602", "E0729"];
 
 fn check_error_code_explanation(
     f: &str,
@@ -114,13 +113,18 @@ fn extract_error_codes(
                 .expect("failed to canonicalize error explanation file path");
             match read_to_string(&path) {
                 Ok(content) => {
-                    if !IGNORE_EXPLANATION_CHECK.contains(&err_code.as_str())
-                        && !check_if_error_code_is_test_in_explanation(&content, &err_code)
-                    {
+                    let has_test = check_if_error_code_is_test_in_explanation(&content, &err_code);
+                    if !has_test && !IGNORE_EXPLANATION_CHECK.contains(&err_code.as_str()) {
                         errors.push(format!(
                             "`{}` doesn't use its own error code in compile_fail example",
                             path.display(),
                         ));
+                    } else if has_test && IGNORE_EXPLANATION_CHECK.contains(&err_code.as_str()) {
+                        errors.push(format!(
+                            "`{}` has a compile_fail example with its own error code, it shouldn't \
+                             be listed in IGNORE_EXPLANATION_CHECK!",
+                            path.display(),
+                        ));
                     }
                     if check_error_code_explanation(&content, error_codes, err_code) {
                         errors.push(format!(
@@ -198,6 +202,11 @@ pub fn check(paths: &[&Path], bad: &mut bool) {
         for (err_code, nb) in &error_codes {
             if !*nb && !EXEMPTED_FROM_TEST.contains(&err_code.as_str()) {
                 errors.push(format!("Error code {} needs to have at least one UI test!", err_code));
+            } else if *nb && EXEMPTED_FROM_TEST.contains(&err_code.as_str()) {
+                errors.push(format!(
+                    "Error code {} has a UI test, it shouldn't be listed into EXEMPTED_FROM_TEST!",
+                    err_code
+                ));
             }
         }
     }