delete no_mangle_span

Co-authored-by: bjorn3 <[email protected]>

Author: alexandruradovici

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -629,11 +629,10 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
         let lang_item =
             lang_items::extract(attrs).map_or(None, |(name, _span)| LangItem::from_name(name));
         // This should never use the default as `no_mangle` is present in the attributes list
-        let no_mangle_span = no_mangle_span.unwrap_or_default();
         let mut err = tcx
             .dcx()
             .struct_span_err(
-                no_mangle_span,
+                no_mangle_span.unwrap_or_default(),
                 "`#[no_mangle]` cannot be used on internal language items",
             )
             .with_note("Rustc requires this item to have a specific mangled name.")