mv compiler to compiler/

compiler/rustc_builtin_macros/src/compile_error.rs

@@ -0,0 +1,20 @@
+// The compiler code necessary to support the compile_error! extension.
+
+use rustc_ast::tokenstream::TokenStream;
+use rustc_expand::base::{self, *};
+use rustc_span::Span;
+
+pub fn expand_compile_error<'cx>(
+    cx: &'cx mut ExtCtxt<'_>,
+    sp: Span,
+    tts: TokenStream,
+) -> Box<dyn base::MacResult + 'cx> {
+    let var = match get_single_str_from_tts(cx, sp, tts, "compile_error!") {
+        None => return DummyResult::any(sp),
+        Some(v) => v,
+    };
+
+    cx.span_err(sp, &var);
+
+    DummyResult::any(sp)
+}