Use core instead of std

Author: smoelius

src/error.rs

@@ -278,9 +278,9 @@ impl ErrorMessage {
             None => (Span::call_site(), Span::call_site()),
         };
 
-        // std::compile_error!($message)
+        // core::compile_error!($message)
         TokenStream::from_iter(vec![
-            TokenTree::Ident(Ident::new("std", start)),
+            TokenTree::Ident(Ident::new("core", start)),
             TokenTree::Punct({
                 let mut punct = Punct::new(':', Spacing::Joint);
                 punct.set_span(start);

tests/test_compile_error.rs

@@ -13,6 +13,6 @@ fn parse_crate_root_custom_inner_attribute() {
     let error = syn::parse2::<Item>(tokens).unwrap_err();
     assert_eq!(
         error.to_compile_error().to_string(),
-        r#"std :: compile_error ! { "expected square brackets" }"#
+        r#"core :: compile_error ! { "expected square brackets" }"#
     );
 }