Auto merge of rust-lang#14974 - max-heller:issue-14958, r=lowr

Properly format documentation for `SignatureHelpRequest`s

Properly formats function documentation instead of returning it raw when responding to `SignatureHelpRequest`s.

I added a test in `crates/rust-analyzer/tests/slow-tests/main.rs` -- not sure if this is the best location given the relevant code is in `crates/rust-analyzer` or if it's possible to test in a less heavyweight manner.

Closes rust-lang#14958

Author: bors

crates/rust-analyzer/src/to_proto.rs

@@ -410,7 +410,7 @@ pub(crate) fn signature_help(
     let documentation = call_info.doc.filter(|_| config.docs).map(|doc| {
         lsp_types::Documentation::MarkupContent(lsp_types::MarkupContent {
             kind: lsp_types::MarkupKind::Markdown,
-            value: doc,
+            value: crate::markdown::format_docs(&doc),
         })
     });
 
@@ -1410,7 +1410,8 @@ pub(crate) fn rename_error(err: RenameError) -> crate::LspError {
 
 #[cfg(test)]
 mod tests {
-    use ide::Analysis;
+    use ide::{Analysis, FilePosition};
+    use test_utils::extract_offset;
     use triomphe::Arc;
 
     use super::*;
@@ -1451,6 +1452,34 @@ fn main() {
         }
     }
 
+    #[test]
+    fn calling_function_with_ignored_code_in_signature() {
+        let text = r#"
+fn foo() {
+    bar($0);
+}
+/// ```
+/// # use crate::bar;
+/// bar(5);
+/// ```
+fn bar(_: usize) {}
+"#;
+
+        let (offset, text) = extract_offset(text);
+        let (analysis, file_id) = Analysis::from_single_file(text);
+        let help = signature_help(
+            analysis.signature_help(FilePosition { file_id, offset }).unwrap().unwrap(),
+            CallInfoConfig { params_only: false, docs: true },
+            false,
+        );
+        let docs = match &help.signatures[help.active_signature.unwrap() as usize].documentation {
+            Some(lsp_types::Documentation::MarkupContent(content)) => &content.value,
+            _ => panic!("documentation contains markup"),
+        };
+        assert!(docs.contains("bar(5)"));
+        assert!(!docs.contains("use crate::bar"));
+    }
+
     // `Url` is not able to parse windows paths on unix machines.
     #[test]
     #[cfg(target_os = "windows")]