Add some more tracing

compiler/rustc_parse/src/lib.rs

@@ -6,6 +6,9 @@
 #![feature(box_patterns)]
 #![recursion_limit = "256"]
 
+#[macro_use]
+extern crate tracing;
+
 use rustc_ast as ast;
 use rustc_ast::token::{self, Nonterminal, Token, TokenKind};
 use rustc_ast::tokenstream::{self, AttributesData, CanSynthesizeMissingTokens, LazyTokenStream};

compiler/rustc_parse/src/parser/expr.rs

@@ -1084,6 +1084,7 @@ impl<'a> Parser<'a> {
 
     /// If we encounter a parser state that looks like the user has written a `struct` literal with
     /// parentheses instead of braces, recover the parser state and provide suggestions.
+    #[instrument(skip(self, seq, snapshot), level = "trace")]
     fn maybe_recover_struct_lit_bad_delims(
         &mut self,
         lo: Span,