librustc_typeck: use diag item instead of string compare

matthewjasper · Jul 18, 2020 · 28e2756 · 28e2756
1 parent d3df851
commit 28e2756
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Showing 2 changed files with 6 additions and 1 deletion.
diff --git a/src/librustc_span/symbol.rs b/src/librustc_span/symbol.rs
@@ -1043,6 +1043,7 @@ symbols! {
         stop_after_dataflow,
         str,
         str_alloc,
+        string_type,
         stringify,
         struct_field_attributes,
         struct_inherit,

diff --git a/src/librustc_typeck/check/op.rs b/src/librustc_typeck/check/op.rs
@@ -562,7 +562,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                    on the left and may require reallocation. This \
                    requires ownership of the string on the left";
 
-        let is_std_string = |ty| &format!("{:?}", ty) == "std::string::String";
+        let string_type = self.tcx.get_diagnostic_item(sym::string_type);
+        let is_std_string = |ty: Ty<'tcx>| match &ty.ty_adt_def() {
+            Some(ty_def) => Some(ty_def.did) == string_type,
+            None => false,
+        };
 
         match (&lhs_ty.kind, &rhs_ty.kind) {
             (&Ref(_, l_ty, _), &Ref(_, r_ty, _)) // &str or &String + &str, &String or &&str