mv compiler to compiler/

compiler/rustc_builtin_macros/src/log_syntax.rs

@@ -0,0 +1,14 @@
+use rustc_ast::tokenstream::TokenStream;
+use rustc_ast_pretty::pprust;
+use rustc_expand::base;
+
+pub fn expand_log_syntax<'cx>(
+    _cx: &'cx mut base::ExtCtxt<'_>,
+    sp: rustc_span::Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'cx> {
+    println!("{}", pprust::tts_to_string(&tts));
+
+    // any so that `log_syntax` can be invoked as an expression and item.
+    base::DummyResult::any_valid(sp)
+}