Use_proc_macro is now equivalent to feature="proc-macro"

Author: dtolnay

build.rs

@@ -1,9 +1,5 @@
 // rustc-cfg emitted by the build script:
 //
-// "use_proc_macro"
-//     Link to extern crate proc_macro. Requires "proc-macro" Cargo cfg to be
-//     enabled (default is enabled).
-//
 // "wrap_proc_macro"
 //     Wrap types from libproc_macro rather than polyfilling the whole API.
 //     Enabled on rustc 1.29+ as long as procmacro2_semver_exempt is not set,
@@ -111,8 +107,6 @@ fn main() {
         return;
     }
 
-    println!("cargo:rustc-cfg=use_proc_macro");
-
     if version.nightly || !semver_exempt {
         println!("cargo:rustc-cfg=wrap_proc_macro");
     }

src/fallback.rs

@@ -233,7 +233,7 @@ impl Debug for TokenStream {
     }
 }
 
-#[cfg(use_proc_macro)]
+#[cfg(feature = "proc-macro")]
 impl From<proc_macro::TokenStream> for TokenStream {
     fn from(inner: proc_macro::TokenStream) -> Self {
         inner
@@ -243,7 +243,7 @@ impl From<proc_macro::TokenStream> for TokenStream {
     }
 }
 
-#[cfg(use_proc_macro)]
+#[cfg(feature = "proc-macro")]
 impl From<TokenStream> for proc_macro::TokenStream {
     fn from(inner: TokenStream) -> Self {
         inner

src/lib.rs

@@ -120,7 +120,7 @@ compile_error! {"\
     build script as well.
 "}
 
-#[cfg(use_proc_macro)]
+#[cfg(feature = "proc-macro")]
 extern crate proc_macro;
 
 mod marker;
@@ -236,14 +236,14 @@ impl FromStr for TokenStream {
     }
 }
 
-#[cfg(use_proc_macro)]
+#[cfg(feature = "proc-macro")]
 impl From<proc_macro::TokenStream> for TokenStream {
     fn from(inner: proc_macro::TokenStream) -> Self {
         TokenStream::_new(inner.into())
     }
 }
 
-#[cfg(use_proc_macro)]
+#[cfg(feature = "proc-macro")]
 impl From<TokenStream> for proc_macro::TokenStream {
     fn from(inner: TokenStream) -> Self {
         inner.inner.into()