Drop Provider API support in pre-1.81 nightlies

Author: dtolnay

build/probe.rs

@@ -4,8 +4,8 @@
 
 #![feature(error_generic_member_access)]
 
+use core::error::{Error, Request};
 use core::fmt::{self, Debug, Display};
-use std::error::{Error, Request};
 
 struct MyError(Thing);
 struct Thing;

impl/src/expand.rs

@@ -143,7 +143,7 @@ fn impl_struct(input: Struct) -> TokenStream {
             }
         };
         quote! {
-            fn provide<'_request>(&'_request self, #request: &mut ::std::error::Request<'_request>) {
+            fn provide<'_request>(&'_request self, #request: &mut ::core::error::Request<'_request>) {
                 #body
             }
         }
@@ -377,7 +377,7 @@ fn impl_enum(input: Enum) -> TokenStream {
             }
         });
         Some(quote! {
-            fn provide<'_request>(&'_request self, #request: &mut ::std::error::Request<'_request>) {
+            fn provide<'_request>(&'_request self, #request: &mut ::core::error::Request<'_request>) {
                 #[allow(deprecated)]
                 match self {
                     #(#arms)*