rustc_builtin_macros/
log_syntax.rs

1use rustc_ast::tokenstream::TokenStream;
2use rustc_ast_pretty::pprust;
3use rustc_expand::base::{DummyResult, ExpandResult, ExtCtxt, MacroExpanderResult};
4
5pub(crate) fn expand_log_syntax<'cx>(
6    _cx: &'cx mut ExtCtxt<'_>,
7    sp: rustc_span::Span,
8    tts: TokenStream,
9) -> MacroExpanderResult<'cx> {
10    println!("{}", pprust::tts_to_string(&tts));
11
12    // any so that `log_syntax` can be invoked as an expression and item.
13    ExpandResult::Ready(DummyResult::any_valid(sp))
14}