Work around deprecation of str::trim_left_matches

serde_derive/src/de.rs

@@ -5,11 +5,11 @@ use syn::spanned::Spanned;
 use syn::{self, Ident, Index, Member};
 
 use bound;
+use dummy;
 use fragment::{Expr, Fragment, Match, Stmts};
 use internals::ast::{Container, Data, Field, Style, Variant};
 use internals::{attr, Ctxt, Derive};
 use pretend;
-use try;
 
 use std::collections::BTreeSet;
 
@@ -25,11 +25,6 @@ pub fn expand_derive_deserialize(input: &syn::DeriveInput) -> Result<TokenStream
     let ident = &cont.ident;
     let params = Parameters::new(&cont);
     let (de_impl_generics, _, ty_generics, where_clause) = split_with_de_lifetime(&params);
-    let suffix = ident.to_string().trim_left_matches("r#").to_owned();
-    let dummy_const = Ident::new(
-        &format!("_IMPL_DESERIALIZE_FOR_{}", suffix),
-        Span::call_site(),
-    );
     let body = Stmts(deserialize_body(&cont, &params));
     let delife = params.borrowed.de_lifetime();
 
@@ -65,19 +60,7 @@ pub fn expand_derive_deserialize(input: &syn::DeriveInput) -> Result<TokenStream
         }
     };
 
-    let try_replacement = try::replacement();
-    let generated = quote! {
-        #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
-        const #dummy_const: () = {
-            #[allow(unknown_lints)]
-            #[cfg_attr(feature = "cargo-clippy", allow(useless_attribute))]
-            #[allow(rust_2018_idioms)]
-            extern crate serde as _serde;
-            #try_replacement
-            #impl_block
-        };
-    };
-    Ok(generated)
+    Ok(dummy::wrap_in_const("DESERIALIZE", ident, impl_block))
 }
 
 fn precondition(cx: &Ctxt, cont: &Container) {