Rollup merge of #63931 - petrochenkov:stabmac, r=Centril

Stabilize macros in some more positions

- Fn-like macros and attribute macros in `extern` blocks
- Fn-like procedural macros in type positions
- ~Attribute macros on inline modules~ (moved to https://github.com/rust-lang/rust/pull/64273)

Stabilization report: https://github.com/rust-lang/rust/pull/63931#issuecomment-526362396.

Closes https://github.com/rust-lang/rust/issues/49476
cc https://github.com/rust-lang/rust/issues/54727

src/librustc_macros/src/lib.rs

@@ -1,4 +1,3 @@
-#![feature(proc_macro_hygiene)]
 #![allow(rustc::default_hash_types)]
 
 #![recursion_limit="128"]

src/libsyntax/ext/expand.rs

@@ -555,15 +555,6 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
     }
 
     fn expand_invoc(&mut self, invoc: Invocation, ext: &SyntaxExtensionKind) -> AstFragment {
-        let (fragment_kind, span) = (invoc.fragment_kind, invoc.span());
-        if fragment_kind == AstFragmentKind::ForeignItems && !self.cx.ecfg.macros_in_extern() {
-            if let SyntaxExtensionKind::NonMacroAttr { .. } = ext {} else {
-                emit_feature_err(&self.cx.parse_sess, sym::macros_in_extern,
-                                 span, GateIssue::Language,
-                                 "macro invocations in `extern {}` blocks are experimental");
-            }
-        }
-
         if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
             let expn_data = self.cx.current_expansion.id.expn_data();
             let suggested_limit = self.cx.ecfg.recursion_limit * 2;
@@ -578,6 +569,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             FatalError.raise();
         }
 
+        let (fragment_kind, span) = (invoc.fragment_kind, invoc.span());
         match invoc.kind {
             InvocationKind::Bang { mac, .. } => match ext {
                 SyntaxExtensionKind::Bang(expander) => {
@@ -758,14 +750,14 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
 
     fn gate_proc_macro_expansion_kind(&self, span: Span, kind: AstFragmentKind) {
         let kind = match kind {
-            AstFragmentKind::Expr => "expressions",
+            AstFragmentKind::Expr |
             AstFragmentKind::OptExpr => "expressions",
             AstFragmentKind::Pat => "patterns",
-            AstFragmentKind::Ty => "types",
             AstFragmentKind::Stmts => "statements",
-            AstFragmentKind::Items => return,
-            AstFragmentKind::TraitItems => return,
-            AstFragmentKind::ImplItems => return,
+            AstFragmentKind::Ty |
+            AstFragmentKind::Items |
+            AstFragmentKind::TraitItems |
+            AstFragmentKind::ImplItems |
             AstFragmentKind::ForeignItems => return,
             AstFragmentKind::Arms
             | AstFragmentKind::Fields
@@ -1578,9 +1570,6 @@ impl<'feat> ExpansionConfig<'feat> {
         }
     }
 
-    fn macros_in_extern(&self) -> bool {
-        self.features.map_or(false, |features| features.macros_in_extern)
-    }
     fn proc_macro_hygiene(&self) -> bool {
         self.features.map_or(false, |features| features.proc_macro_hygiene)
     }

src/libsyntax/feature_gate/accepted.rs

@@ -245,6 +245,8 @@ declare_features! (
     (accepted, bind_by_move_pattern_guards, "1.39.0", Some(15287), None),
     /// Allows attributes in formal function parameters.
     (accepted, param_attrs, "1.39.0", Some(60406), None),
+    // Allows macro invocations in `extern {}` blocks.
+    (accepted, macros_in_extern, "1.40.0", Some(49476), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: accepted features

src/libsyntax/feature_gate/active.rs

@@ -402,9 +402,6 @@ declare_features! (
     /// Allows infering `'static` outlives requirements (RFC 2093).
     (active, infer_static_outlives_requirements, "1.26.0", Some(54185), None),
 
-    /// Allows macro invocations in `extern {}` blocks.
-    (active, macros_in_extern, "1.27.0", Some(49476), None),
-
     /// Allows accessing fields of unions inside `const` functions.
     (active, const_fn_union, "1.27.0", Some(51909), None),
 

src/test/ui/abi/macros/macros-in-extern.stderr

@@ -1,30 +0,0 @@
-error[E0658]: macro invocations in `extern {}` blocks are experimental
-  --> $DIR/macros-in-extern.rs:26:5
-   |
-LL |     returns_isize!(rust_get_test_int);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/49476
-   = help: add `#![feature(macros_in_extern)]` to the crate attributes to enable
-
-error[E0658]: macro invocations in `extern {}` blocks are experimental
-  --> $DIR/macros-in-extern.rs:28:5
-   |
-LL |     takes_u32_returns_u32!(rust_dbg_extern_identity_u32);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/49476
-   = help: add `#![feature(macros_in_extern)]` to the crate attributes to enable
-
-error[E0658]: macro invocations in `extern {}` blocks are experimental
-  --> $DIR/macros-in-extern.rs:30:5
-   |
-LL |     emits_nothing!();
-   |     ^^^^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/49476
-   = help: add `#![feature(macros_in_extern)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0658`.

src/test/ui/abi/proc-macro/auxiliary/test-macros.rs

@@ -1,112 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-// Proc macros commonly used by tests.
-// `panic`/`print` -> `panic_bang`/`print_bang` to avoid conflicts with standard macros.
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-use proc_macro::TokenStream;
-
-// Macro that return empty token stream.
-
-#[proc_macro]
-pub fn empty(_: TokenStream) -> TokenStream {
-    TokenStream::new()
-}
-
-#[proc_macro_attribute]
-pub fn empty_attr(_: TokenStream, _: TokenStream) -> TokenStream {
-    TokenStream::new()
-}
-
-#[proc_macro_derive(Empty, attributes(empty_helper))]
-pub fn empty_derive(_: TokenStream) -> TokenStream {
-    TokenStream::new()
-}
-
-// Macro that panics.
-
-#[proc_macro]
-pub fn panic_bang(_: TokenStream) -> TokenStream {
-    panic!("panic-bang");
-}
-
-#[proc_macro_attribute]
-pub fn panic_attr(_: TokenStream, _: TokenStream) -> TokenStream {
-    panic!("panic-attr");
-}
-
-#[proc_macro_derive(Panic, attributes(panic_helper))]
-pub fn panic_derive(_: TokenStream) -> TokenStream {
-    panic!("panic-derive");
-}
-
-// Macros that return the input stream.
-
-#[proc_macro]
-pub fn identity(input: TokenStream) -> TokenStream {
-    input
-}
-
-#[proc_macro_attribute]
-pub fn identity_attr(_: TokenStream, input: TokenStream) -> TokenStream {
-    input
-}
-
-#[proc_macro_derive(Identity, attributes(identity_helper))]
-pub fn identity_derive(input: TokenStream) -> TokenStream {
-    input
-}
-
-// Macros that iterate and re-collect the input stream.
-
-#[proc_macro]
-pub fn recollect(input: TokenStream) -> TokenStream {
-    input.into_iter().collect()
-}
-
-#[proc_macro_attribute]
-pub fn recollect_attr(_: TokenStream, input: TokenStream) -> TokenStream {
-    input.into_iter().collect()
-}
-
-#[proc_macro_derive(Recollect, attributes(recollect_helper))]
-pub fn recollect_derive(input: TokenStream) -> TokenStream {
-    input.into_iter().collect()
-}
-
-// Macros that print their input in the original and re-collected forms (if they differ).
-
-fn print_helper(input: TokenStream, kind: &str) -> TokenStream {
-    let input_display = format!("{}", input);
-    let input_debug = format!("{:#?}", input);
-    let recollected = input.into_iter().collect();
-    let recollected_display = format!("{}", recollected);
-    let recollected_debug = format!("{:#?}", recollected);
-    println!("PRINT-{} INPUT (DISPLAY): {}", kind, input_display);
-    if recollected_display != input_display {
-        println!("PRINT-{} RE-COLLECTED (DISPLAY): {}", kind, recollected_display);
-    }
-    println!("PRINT-{} INPUT (DEBUG): {}", kind, input_debug);
-    if recollected_debug != input_debug {
-        println!("PRINT-{} RE-COLLECTED (DEBUG): {}", kind, recollected_debug);
-    }
-    recollected
-}
-
-#[proc_macro]
-pub fn print_bang(input: TokenStream) -> TokenStream {
-    print_helper(input, "BANG")
-}
-
-#[proc_macro_attribute]
-pub fn print_attr(_: TokenStream, input: TokenStream) -> TokenStream {
-    print_helper(input, "ATTR")
-}
-
-#[proc_macro_derive(Print, attributes(print_helper))]
-pub fn print_derive(input: TokenStream) -> TokenStream {
-    print_helper(input, "DERIVE")
-}

src/test/ui/abi/proc-macro/macros-in-extern.stderr

@@ -1,30 +0,0 @@
-error[E0658]: macro invocations in `extern {}` blocks are experimental
-  --> $DIR/macros-in-extern.rs:14:5
-   |
-LL |     #[empty_attr]
-   |     ^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/49476
-   = help: add `#![feature(macros_in_extern)]` to the crate attributes to enable
-
-error[E0658]: macro invocations in `extern {}` blocks are experimental
-  --> $DIR/macros-in-extern.rs:18:5
-   |
-LL |     #[identity_attr]
-   |     ^^^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/49476
-   = help: add `#![feature(macros_in_extern)]` to the crate attributes to enable
-
-error[E0658]: macro invocations in `extern {}` blocks are experimental
-  --> $DIR/macros-in-extern.rs:22:5
-   |
-LL |     identity!(fn rust_dbg_extern_identity_u32(arg: u32) -> u32;);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/49476
-   = help: add `#![feature(macros_in_extern)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0658`.

src/test/ui/feature-gates/feature-gate-macros_in_extern.rs

@@ -1,27 +0,0 @@
-#![feature(decl_macro)]
-
-macro_rules! returns_isize(
-    ($ident:ident) => (
-        fn $ident() -> isize;
-    )
-);
-
-macro takes_u32_returns_u32($ident:ident) {
-    fn $ident (arg: u32) -> u32;
-}
-
-macro_rules! emits_nothing(
-    () => ()
-);
-
-#[link(name = "rust_test_helpers", kind = "static")]
-extern {
-    returns_isize!(rust_get_test_int);
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental
-    takes_u32_returns_u32!(rust_dbg_extern_identity_u32);
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental
-    emits_nothing!();
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental
-}
-
-fn main() {}

src/test/ui/feature-gates/feature-gate-macros_in_extern.stderr

@@ -1,30 +0,0 @@
-error[E0658]: macro invocations in `extern {}` blocks are experimental
-  --> $DIR/feature-gate-macros_in_extern.rs:19:5
-   |
-LL |     returns_isize!(rust_get_test_int);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/49476
-   = help: add `#![feature(macros_in_extern)]` to the crate attributes to enable
-
-error[E0658]: macro invocations in `extern {}` blocks are experimental
-  --> $DIR/feature-gate-macros_in_extern.rs:21:5
-   |
-LL |     takes_u32_returns_u32!(rust_dbg_extern_identity_u32);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/49476
-   = help: add `#![feature(macros_in_extern)]` to the crate attributes to enable
-
-error[E0658]: macro invocations in `extern {}` blocks are experimental
-  --> $DIR/feature-gate-macros_in_extern.rs:23:5
-   |
-LL |     emits_nothing!();
-   |     ^^^^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/49476
-   = help: add `#![feature(macros_in_extern)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0658`.

src/test/ui/macros/issue-54441.rs

@@ -1,5 +1,3 @@
-#![feature(macros_in_extern)]
-
 macro_rules! m {
     () => {
         let //~ ERROR expected

src/test/ui/macros/issue-54441.stderr

@@ -1,5 +1,5 @@
 error: expected one of `crate`, `fn`, `pub`, `static`, or `type`, found `let`
-  --> $DIR/issue-54441.rs:5:9
+  --> $DIR/issue-54441.rs:3:9
    |
 LL |         let
    |         ^^^ unexpected token

src/test/ui/macros/macros-in-extern-rpass.rs

@@ -1,30 +0,0 @@
-// run-pass
-// ignore-wasm32
-
-#![feature(decl_macro, macros_in_extern)]
-
-macro_rules! returns_isize(
-    ($ident:ident) => (
-        fn $ident() -> isize;
-    )
-);
-
-macro takes_u32_returns_u32($ident:ident) {
-    fn $ident (arg: u32) -> u32;
-}
-
-macro_rules! emits_nothing(
-    () => ()
-);
-
-fn main() {
-    assert_eq!(unsafe { rust_get_test_int() }, 1isize);
-    assert_eq!(unsafe { rust_dbg_extern_identity_u32(0xDEADBEEF) }, 0xDEADBEEFu32);
-}
-
-#[link(name = "rust_test_helpers", kind = "static")]
-extern {
-    returns_isize!(rust_get_test_int);
-    takes_u32_returns_u32!(rust_dbg_extern_identity_u32);
-    emits_nothing!();
-}

src/test/ui/macros/macros-in-extern.rs

@@ -1,3 +1,4 @@
+// run-pass
 // ignore-wasm32
 
 #![feature(decl_macro)]
@@ -16,17 +17,29 @@ macro_rules! emits_nothing(
     () => ()
 );
 
+macro_rules! emits_multiple(
+    () => {
+        fn f1() -> u32;
+        fn f2() -> u32;
+    }
+);
+
+mod defs {
+    #[no_mangle] extern fn f1() -> u32 { 1 }
+    #[no_mangle] extern fn f2() -> u32 { 2 }
+}
+
 fn main() {
-    assert_eq!(unsafe { rust_get_test_int() }, 0isize);
+    assert_eq!(unsafe { rust_get_test_int() }, 1);
     assert_eq!(unsafe { rust_dbg_extern_identity_u32(0xDEADBEEF) }, 0xDEADBEEFu32);
+    assert_eq!(unsafe { f1() }, 1);
+    assert_eq!(unsafe { f2() }, 2);
 }
 
 #[link(name = "rust_test_helpers", kind = "static")]
 extern {
     returns_isize!(rust_get_test_int);
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental
     takes_u32_returns_u32!(rust_dbg_extern_identity_u32);
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental
     emits_nothing!();
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental
+    emits_multiple!();
 }

src/test/ui/proc-macro/auxiliary/test-macros-rpass.rs

@@ -1,26 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::TokenStream;
-
-#[proc_macro_attribute]
-pub fn nop_attr(_attr: TokenStream, input: TokenStream) -> TokenStream {
-    assert!(_attr.to_string().is_empty());
-    input
-}
-
-#[proc_macro_attribute]
-pub fn no_output(_attr: TokenStream, _input: TokenStream) -> TokenStream {
-    assert!(_attr.to_string().is_empty());
-    assert!(!_input.to_string().is_empty());
-    "".parse().unwrap()
-}
-
-#[proc_macro]
-pub fn emit_input(input: TokenStream) -> TokenStream {
-    input
-}

src/test/ui/proc-macro/dollar-crate-issue-62325.rs

@@ -7,8 +7,6 @@
 // normalize-stdout-test "bytes\([^0]\w*\.\.(\w+)\)" -> "bytes(LO..$1)"
 // normalize-stdout-test "bytes\((\w+)\.\.[^0]\w*\)" -> "bytes($1..HI)"
 
-#![feature(proc_macro_hygiene)]
-
 #[macro_use]
 extern crate test_macros;
 extern crate dollar_crate_external;

src/test/ui/proc-macro/lifetimes.rs

@@ -1,7 +1,5 @@
 // aux-build:lifetimes.rs
 
-#![feature(proc_macro_hygiene)]
-
 extern crate lifetimes;
 
 use lifetimes::*;

src/test/ui/proc-macro/lifetimes.stderr

@@ -1,5 +1,5 @@
 error: expected type, found `'`
-  --> $DIR/lifetimes.rs:9:10
+  --> $DIR/lifetimes.rs:7:10
    |
 LL | type A = single_quote_alone!();
    |          ^^^^^^^^^^^^^^^^^^^^^ this macro call doesn't expand to a type

src/test/ui/proc-macro/macros-in-extern-derive.rs

@@ -0,0 +1,6 @@
+extern {
+    #[derive(Copy)] //~ ERROR `derive` may only be applied to structs, enums and unions
+    fn f();
+}
+
+fn main() {}

src/test/ui/proc-macro/macros-in-extern-derive.stderr

@@ -0,0 +1,8 @@
+error: `derive` may only be applied to structs, enums and unions
+  --> $DIR/macros-in-extern-derive.rs:2:5
+   |
+LL |     #[derive(Copy)]
+   |     ^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+

src/test/ui/proc-macro/macros-in-extern-rpass.rs

@@ -1,25 +0,0 @@
-// run-pass
-// aux-build:test-macros-rpass.rs
-// ignore-wasm32
-
-#![feature(macros_in_extern)]
-
-extern crate test_macros_rpass as test_macros;
-
-use test_macros::{nop_attr, no_output, emit_input};
-
-fn main() {
-    assert_eq!(unsafe { rust_get_test_int() }, 1isize);
-    assert_eq!(unsafe { rust_dbg_extern_identity_u32(0xDEADBEEF) }, 0xDEADBEEF);
-}
-
-#[link(name = "rust_test_helpers", kind = "static")]
-extern {
-    #[no_output]
-    fn some_definitely_unknown_symbol_which_should_be_removed();
-
-    #[nop_attr]
-    fn rust_get_test_int() -> isize;
-
-    emit_input!(fn rust_dbg_extern_identity_u32(arg: u32) -> u32;);
-}

src/test/ui/proc-macro/macros-in-extern.rs

@@ -1,3 +1,4 @@
+// run-pass
 // aux-build:test-macros.rs
 // ignore-wasm32
 
@@ -5,20 +6,17 @@
 extern crate test_macros;
 
 fn main() {
-    assert_eq!(unsafe { rust_get_test_int() }, 0isize);
+    assert_eq!(unsafe { rust_get_test_int() }, 1);
     assert_eq!(unsafe { rust_dbg_extern_identity_u32(0xDEADBEEF) }, 0xDEADBEEF);
 }
 
 #[link(name = "rust_test_helpers", kind = "static")]
 extern {
     #[empty_attr]
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental
     fn some_definitely_unknown_symbol_which_should_be_removed();
 
     #[identity_attr]
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental
     fn rust_get_test_int() -> isize;
 
     identity!(fn rust_dbg_extern_identity_u32(arg: u32) -> u32;);
-    //~^ ERROR macro invocations in `extern {}` blocks are experimental
 }

src/test/ui/proc-macro/macros-in-type.rs

@@ -0,0 +1,11 @@
+// check-pass
+// aux-build:test-macros.rs
+
+#[macro_use]
+extern crate test_macros;
+
+const C: identity!(u8) = 10;
+
+fn main() {
+    let c: u8 = C;
+}

src/test/ui/proc-macro/proc-macro-gates.rs

@@ -50,7 +50,6 @@ fn attrs() {
 }
 
 fn main() {
-    let _x: identity!(u32) = 3; //~ ERROR: procedural macros cannot be expanded to types
     if let identity!(Some(_x)) = Some(3) {}
     //~^ ERROR: procedural macros cannot be expanded to patterns
 

src/test/ui/proc-macro/proc-macro-gates.stderr

@@ -94,17 +94,8 @@ LL |     let _x = #[identity_attr] println!();
    = note: for more information, see https://github.com/rust-lang/rust/issues/54727
    = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
 
-error[E0658]: procedural macros cannot be expanded to types
-  --> $DIR/proc-macro-gates.rs:53:13
-   |
-LL |     let _x: identity!(u32) = 3;
-   |             ^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/54727
-   = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
-
 error[E0658]: procedural macros cannot be expanded to patterns
-  --> $DIR/proc-macro-gates.rs:54:12
+  --> $DIR/proc-macro-gates.rs:53:12
    |
 LL |     if let identity!(Some(_x)) = Some(3) {}
    |            ^^^^^^^^^^^^^^^^^^^
@@ -113,7 +104,7 @@ LL |     if let identity!(Some(_x)) = Some(3) {}
    = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
 
 error[E0658]: procedural macros cannot be expanded to statements
-  --> $DIR/proc-macro-gates.rs:57:5
+  --> $DIR/proc-macro-gates.rs:56:5
    |
 LL |     empty!(struct S;);
    |     ^^^^^^^^^^^^^^^^^^
@@ -122,7 +113,7 @@ LL |     empty!(struct S;);
    = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
 
 error[E0658]: procedural macros cannot be expanded to statements
-  --> $DIR/proc-macro-gates.rs:58:5
+  --> $DIR/proc-macro-gates.rs:57:5
    |
 LL |     empty!(let _x = 3;);
    |     ^^^^^^^^^^^^^^^^^^^^
@@ -131,7 +122,7 @@ LL |     empty!(let _x = 3;);
    = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
 
 error[E0658]: procedural macros cannot be expanded to expressions
-  --> $DIR/proc-macro-gates.rs:60:14
+  --> $DIR/proc-macro-gates.rs:59:14
    |
 LL |     let _x = identity!(3);
    |              ^^^^^^^^^^^^
@@ -140,7 +131,7 @@ LL |     let _x = identity!(3);
    = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
 
 error[E0658]: procedural macros cannot be expanded to expressions
-  --> $DIR/proc-macro-gates.rs:61:15
+  --> $DIR/proc-macro-gates.rs:60:15
    |
 LL |     let _x = [empty!(3)];
    |               ^^^^^^^^^
@@ -148,6 +139,6 @@ LL |     let _x = [empty!(3)];
    = note: for more information, see https://github.com/rust-lang/rust/issues/54727
    = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
 
-error: aborting due to 17 previous errors
+error: aborting due to 16 previous errors
 
 For more information about this error, try `rustc --explain E0658`.