Collect all matching messages for a lint.

Some examples may contain multiple lines which trigger the lint.
Previously it would only display the first message.
This updates it so that all matching instances of the lint are displayed.

Author: ehuss

src/tools/lint-docs/src/lib.rs

@@ -422,37 +422,36 @@ impl<'a> LintExtractor<'a> {
             .filter(|line| line.starts_with('{'))
             .map(serde_json::from_str)
             .collect::<Result<Vec<serde_json::Value>, _>>()?;
-        match msgs
+        // First try to find the messages with the `code` field set to our lint.
+        let matches: Vec<_> = msgs
             .iter()
-            .find(|msg| matches!(&msg["code"]["code"], serde_json::Value::String(s) if s==name))
-        {
-            Some(msg) => {
-                let rendered = msg["rendered"].as_str().expect("rendered field should exist");
-                Ok(rendered.to_string())
-            }
-            None => {
-                match msgs.iter().find(
-                    |msg| matches!(&msg["rendered"], serde_json::Value::String(s) if s.contains(name)),
-                ) {
-                    Some(msg) => {
-                        let rendered = msg["rendered"].as_str().expect("rendered field should exist");
-                        Ok(rendered.to_string())
-                    }
-                    None => {
-                        let rendered: Vec<&str> =
-                            msgs.iter().filter_map(|msg| msg["rendered"].as_str()).collect();
-                        let non_json: Vec<&str> =
-                            stderr.lines().filter(|line| !line.starts_with('{')).collect();
-                        Err(format!(
-                            "did not find lint `{}` in output of example, got:\n{}\n{}",
-                            name,
-                            non_json.join("\n"),
-                            rendered.join("\n")
-                        )
-                        .into())
-                    }
-                }
+            .filter(|msg| matches!(&msg["code"]["code"], serde_json::Value::String(s) if s==name))
+            .map(|msg| msg["rendered"].as_str().expect("rendered field should exist").to_string())
+            .collect();
+        if matches.is_empty() {
+            // Some lints override their code to something else (E0566).
+            // Try to find something that looks like it could be our lint.
+            let matches: Vec<_> = msgs.iter().filter(|msg|
+                matches!(&msg["rendered"], serde_json::Value::String(s) if s.contains(name)))
+                .map(|msg| msg["rendered"].as_str().expect("rendered field should exist").to_string())
+                .collect();
+            if matches.is_empty() {
+                let rendered: Vec<&str> =
+                    msgs.iter().filter_map(|msg| msg["rendered"].as_str()).collect();
+                let non_json: Vec<&str> =
+                    stderr.lines().filter(|line| !line.starts_with('{')).collect();
+                Err(format!(
+                    "did not find lint `{}` in output of example, got:\n{}\n{}",
+                    name,
+                    non_json.join("\n"),
+                    rendered.join("\n")
+                )
+                .into())
+            } else {
+                Ok(matches.join("\n"))
             }
+        } else {
+            Ok(matches.join("\n"))
         }
     }