Merge #2133

2133: Document match_ast! and use it in call_info r=matklad a=kjeremy

Suggested by @matklad in https://github.com/rust-analyzer/rust-analyzer/pull/2129#discussion_r340708660

Co-authored-by: kjeremy <[email protected]>

1 files changed, 14 insertions, 0 deletions

diff --git a/crates/ra_syntax/src/lib.rs b/crates/ra_syntax/src/lib.rs
index c315ba552..5dcb6a95a 100644
--- a/crates/ra_syntax/src/lib.rs
+++ b/crates/ra_syntax/src/lib.rs
@@ -160,6 +160,20 @@ impl SourceFile {
     }
 }
 
+/// Matches a `SyntaxNode` against an `ast` type.
+///
+/// # Example:
+///
+/// ```ignore
+/// match_ast! {
+///     match node {
+///         ast::CallExpr(it) => { ... },
+///         ast::MethodCallExpr(it) => { ... },
+///         ast::MacroCall(it) => { ... },
+///         _ => None,
+///     }
+/// }
+/// ```
 #[macro_export]
 macro_rules! match_ast {
     (match $node:ident {