Rollup merge of #61024 - petrochenkov:proctest, r=nikomatsakis

tests: Centralize proc macros commonly used for testing

Many proc macros in `ui\proc-macro\auxiliary` were doing same things.
(I added a fair share of those myself.)

Now commonly used macros (empty, identity, etc) are collected in one place - `ui\proc-macro\auxiliary\test-macros.rs`.

src/test/ui/custom-derive/auxiliary/plugin.rs

@@ -1,28 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::TokenStream;
-
-#[proc_macro_derive(Foo)]
-pub fn derive_foo(input: TokenStream) -> TokenStream {
-    input
-}
-
-#[proc_macro_derive(Bar)]
-pub fn derive_bar(input: TokenStream) -> TokenStream {
-    panic!("lolnope");
-}
-
-#[proc_macro_derive(WithHelper, attributes(helper))]
-pub fn with_helper(input: TokenStream) -> TokenStream {
-    TokenStream::new()
-}
-
-#[proc_macro_attribute]
-pub fn helper(_: TokenStream, input: TokenStream) -> TokenStream {
-    input
-}

src/test/ui/custom-derive/derive-in-mod.rs

@@ -1,13 +0,0 @@
-// compile-pass
-// aux-build:plugin.rs
-
-extern crate plugin;
-
-mod inner {
-    use plugin::WithHelper;
-
-    #[derive(WithHelper)]
-    struct S;
-}
-
-fn main() {}

src/test/ui/custom-derive/helper-attr-blocked-by-import-ambig.rs

@@ -1,12 +0,0 @@
-// aux-build:plugin.rs
-
-#[macro_use(WithHelper)]
-extern crate plugin;
-
-use plugin::helper;
-
-#[derive(WithHelper)]
-#[helper] //~ ERROR `helper` is ambiguous
-struct S;
-
-fn main() {}

src/test/ui/custom-derive/helper-attr-blocked-by-import-ambig.stderr

@@ -1,21 +0,0 @@
-error[E0659]: `helper` is ambiguous (derive helper attribute vs any other name)
-  --> $DIR/helper-attr-blocked-by-import-ambig.rs:9:3
-   |
-LL | #[helper]
-   |   ^^^^^^ ambiguous name
-   |
-note: `helper` could refer to the derive helper attribute defined here
-  --> $DIR/helper-attr-blocked-by-import-ambig.rs:8:10
-   |
-LL | #[derive(WithHelper)]
-   |          ^^^^^^^^^^
-note: `helper` could also refer to the attribute macro imported here
-  --> $DIR/helper-attr-blocked-by-import-ambig.rs:6:5
-   |
-LL | use plugin::helper;
-   |     ^^^^^^^^^^^^^^
-   = help: use `crate::helper` to refer to this attribute macro unambiguously
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0659`.

src/test/ui/custom-derive/helper-attr-blocked-by-import.rs

@@ -1,28 +0,0 @@
-// compile-pass
-// aux-build:plugin.rs
-
-#[macro_use(WithHelper)]
-extern crate plugin;
-
-use self::one::*;
-use self::two::*;
-
-mod helper {}
-
-mod one {
-    use helper;
-
-    #[derive(WithHelper)]
-    #[helper]
-    struct One;
-}
-
-mod two {
-    use helper;
-
-    #[derive(WithHelper)]
-    #[helper]
-    struct Two;
-}
-
-fn main() {}

src/test/ui/custom-derive/issue-36935.rs

@@ -1,12 +0,0 @@
-// aux-build:plugin.rs
-
-
-#[macro_use] extern crate plugin;
-
-#[derive(Foo, Bar)] //~ ERROR proc-macro derive panicked
-struct Baz {
-    a: i32,
-    b: i32,
-}
-
-fn main() {}

src/test/ui/custom-derive/issue-36935.stderr

@@ -1,10 +0,0 @@
-error: proc-macro derive panicked
-  --> $DIR/issue-36935.rs:6:15
-   |
-LL | #[derive(Foo, Bar)]
-   |               ^^^
-   |
-   = help: message: lolnope
-
-error: aborting due to previous error
-

src/test/ui/proc-macro/attribute-order-restricted.rs

@@ -1,14 +1,14 @@
-// aux-build:attr_proc_macro.rs
+// aux-build:test-macros.rs
 
-extern crate attr_proc_macro;
-use attr_proc_macro::*;
+#[macro_use]
+extern crate test_macros;
 
-#[attr_proc_macro] // OK
+#[identity_attr] // OK
 #[derive(Clone)]
 struct Before;
 
 #[derive(Clone)]
-#[attr_proc_macro] //~ ERROR macro attributes must be placed before `#[derive]`
+#[identity_attr] //~ ERROR macro attributes must be placed before `#[derive]`
 struct After;
 
 fn main() {}

src/test/ui/proc-macro/attribute-order-restricted.stderr

@@ -1,8 +1,8 @@
 error: macro attributes must be placed before `#[derive]`
   --> $DIR/attribute-order-restricted.rs:11:1
    |
-LL | #[attr_proc_macro]
-   | ^^^^^^^^^^^^^^^^^^
+LL | #[identity_attr]
+   | ^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 

src/test/ui/proc-macro/attribute-with-error.rs

@@ -1,12 +1,11 @@
-// aux-build:attribute-with-error.rs
+// aux-build:test-macros.rs
 
 #![feature(custom_inner_attributes)]
 
-extern crate attribute_with_error;
+#[macro_use]
+extern crate test_macros;
 
-use attribute_with_error::foo;
-
-#[foo]
+#[recollect_attr]
 fn test1() {
     let a: i32 = "foo";
     //~^ ERROR: mismatched types
@@ -15,13 +14,13 @@ fn test1() {
 }
 
 fn test2() {
-    #![foo]
+    #![recollect_attr]
 
     // FIXME: should have a type error here and assert it works but it doesn't
 }
 
 trait A {
-    // FIXME: should have a #[foo] attribute here and assert that it works
+    // FIXME: should have a #[recollect_attr] attribute here and assert that it works
     fn foo(&self) {
         let a: i32 = "foo";
         //~^ ERROR: mismatched types
@@ -31,13 +30,13 @@ trait A {
 struct B;
 
 impl A for B {
-    #[foo]
+    #[recollect_attr]
     fn foo(&self) {
         let a: i32 = "foo";
         //~^ ERROR: mismatched types
     }
 }
 
-#[foo]
+#[recollect_attr]
 fn main() {
 }

src/test/ui/proc-macro/attribute-with-error.stderr

@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/attribute-with-error.rs:11:18
+  --> $DIR/attribute-with-error.rs:10:18
    |
 LL |     let a: i32 = "foo";
    |                  ^^^^^ expected i32, found reference
@@ -8,7 +8,7 @@ LL |     let a: i32 = "foo";
               found type `&'static str`
 
 error[E0308]: mismatched types
-  --> $DIR/attribute-with-error.rs:13:18
+  --> $DIR/attribute-with-error.rs:12:18
    |
 LL |     let b: i32 = "f'oo";
    |                  ^^^^^^ expected i32, found reference
@@ -17,7 +17,7 @@ LL |     let b: i32 = "f'oo";
               found type `&'static str`
 
 error[E0308]: mismatched types
-  --> $DIR/attribute-with-error.rs:26:22
+  --> $DIR/attribute-with-error.rs:25:22
    |
 LL |         let a: i32 = "foo";
    |                      ^^^^^ expected i32, found reference
@@ -26,7 +26,7 @@ LL |         let a: i32 = "foo";
               found type `&'static str`
 
 error[E0308]: mismatched types
-  --> $DIR/attribute-with-error.rs:36:22
+  --> $DIR/attribute-with-error.rs:35:22
    |
 LL |         let a: i32 = "foo";
    |                      ^^^^^ expected i32, found reference

src/test/ui/proc-macro/auxiliary/attr_proc_macro.rs

@@ -1,13 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::TokenStream;
-
-#[proc_macro_attribute]
-pub fn attr_proc_macro(_: TokenStream, input: TokenStream) -> TokenStream {
-    input
-}

src/test/ui/proc-macro/auxiliary/attribute-with-error.rs

@@ -1,13 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::TokenStream;
-
-#[proc_macro_attribute]
-pub fn foo(_attr: TokenStream, input: TokenStream) -> TokenStream {
-    input.into_iter().collect()
-}

src/test/ui/proc-macro/auxiliary/bang_proc_macro.rs

@@ -1,13 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::TokenStream;
-
-#[proc_macro]
-pub fn bang_proc_macro(input: TokenStream) -> TokenStream {
-    input
-}

src/test/ui/proc-macro/auxiliary/derive-a-b.rs

@@ -1,17 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-use proc_macro::TokenStream;
-
-#[proc_macro_derive(A)]
-pub fn derive_a(_: TokenStream) -> TokenStream {
-    "".parse().unwrap()
-}
-
-#[proc_macro_derive(B)]
-pub fn derive_b(_: TokenStream) -> TokenStream {
-    "".parse().unwrap()
-}

src/test/ui/proc-macro/auxiliary/derive-a.rs

@@ -1,13 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::TokenStream;
-
-#[proc_macro_derive(A)]
-pub fn derive_a(input: TokenStream) -> TokenStream {
-    "".parse().unwrap()
-}

src/test/ui/proc-macro/auxiliary/derive-helper-shadowed-2.rs

@@ -1,2 +1,2 @@
 #[macro_export]
-macro_rules! my_attr { () => () }
+macro_rules! empty_helper { () => () }

src/test/ui/proc-macro/auxiliary/derive-helper-shadowed.rs

@@ -1,12 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-use proc_macro::*;
-
-#[proc_macro_derive(MyTrait, attributes(my_attr))]
-pub fn foo(_: TokenStream) -> TokenStream {
-    TokenStream::new()
-}

src/test/ui/proc-macro/auxiliary/derive-helper-shadowing.rs

@@ -1,17 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-use proc_macro::*;
-
-#[proc_macro_attribute]
-pub fn my_attr(_: TokenStream, input: TokenStream) -> TokenStream {
-    input
-}
-
-#[proc_macro_derive(MyTrait, attributes(my_attr))]
-pub fn derive(input: TokenStream) -> TokenStream {
-    TokenStream::new()
-}

src/test/ui/proc-macro/auxiliary/derive-panic.rs

@@ -1,13 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::TokenStream;
-
-#[proc_macro_derive(A)]
-pub fn derive_a(_input: TokenStream) -> TokenStream {
-    panic!("nope!");
-}

src/test/ui/proc-macro/auxiliary/dollar-crate-external.rs

@@ -3,14 +3,14 @@ pub type S = u8;
 #[macro_export]
 macro_rules! external {
     () => {
-        dollar_crate::m! {
+        print_bang! {
             struct M($crate::S);
         }
 
-        #[dollar_crate::a]
+        #[print_attr]
         struct A($crate::S);
 
-        #[derive(dollar_crate::d)]
+        #[derive(Print)]
         struct D($crate::S);
     };
 }

src/test/ui/proc-macro/auxiliary/dollar-crate.rs

@@ -1,35 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-use proc_macro::TokenStream;
-
-#[proc_macro]
-pub fn m_empty(input: TokenStream) -> TokenStream {
-    println!("PROC MACRO INPUT (PRETTY-PRINTED): {}", input);
-    println!("PROC MACRO INPUT: {:#?}", input);
-    TokenStream::new()
-}
-
-#[proc_macro]
-pub fn m(input: TokenStream) -> TokenStream {
-    println!("PROC MACRO INPUT (PRETTY-PRINTED): {}", input);
-    println!("PROC MACRO INPUT: {:#?}", input);
-    input.into_iter().collect()
-}
-
-#[proc_macro_attribute]
-pub fn a(_args: TokenStream, input: TokenStream) -> TokenStream {
-    println!("ATTRIBUTE INPUT (PRETTY-PRINTED): {}", input);
-    println!("ATTRIBUTE INPUT: {:#?}", input);
-    input.into_iter().collect()
-}
-
-#[proc_macro_derive(d)]
-pub fn d(input: TokenStream) -> TokenStream {
-    println!("DERIVE INPUT (PRETTY-PRINTED): {}", input);
-    println!("DERIVE INPUT: {:#?}", input);
-    input.into_iter().collect()
-}

src/test/ui/proc-macro/auxiliary/issue-41211.rs

@@ -1,12 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-use proc_macro::TokenStream;
-
-#[proc_macro_attribute]
-pub fn emit_unchanged(_args: TokenStream, input: TokenStream) -> TokenStream {
-    input
-}

src/test/ui/proc-macro/auxiliary/issue-53481.rs

@@ -1,13 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::*;
-
-#[proc_macro_derive(MyTrait, attributes(my_attr))]
-pub fn foo(_: TokenStream) -> TokenStream {
-    TokenStream::new()
-}

src/test/ui/proc-macro/auxiliary/macro-brackets.rs

@@ -1,12 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-use proc_macro::*;
-
-#[proc_macro_attribute]
-pub fn doit(_: TokenStream, input: TokenStream) -> TokenStream {
-    input.into_iter().collect()
-}

src/test/ui/proc-macro/auxiliary/nested-item-spans.rs

@@ -1,13 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::*;
-
-#[proc_macro_attribute]
-pub fn foo(_: TokenStream, item: TokenStream) -> TokenStream {
-    item.into_iter().collect()
-}

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

@@ -1,18 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::*;
-
-#[proc_macro]
-pub fn m(a: TokenStream) -> TokenStream {
-    a
-}
-
-#[proc_macro_attribute]
-pub fn a(_a: TokenStream, b: TokenStream) -> TokenStream {
-    b
-}

src/test/ui/proc-macro/auxiliary/span-preservation.rs

@@ -1,13 +0,0 @@
-// force-host
-// no-prefer-dynamic
-
-#![crate_type = "proc-macro"]
-
-extern crate proc_macro;
-
-use proc_macro::TokenStream;
-
-#[proc_macro_attribute]
-pub fn foo(_: TokenStream, input: TokenStream) -> TokenStream {
-    input.into_iter().collect()
-}

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

@@ -1,26 +1,112 @@
 // 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 nop_attr(_attr: TokenStream, input: TokenStream) -> TokenStream {
-    assert!(_attr.to_string().is_empty());
+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 no_output(_attr: TokenStream, _input: TokenStream) -> TokenStream {
-    assert!(_attr.to_string().is_empty());
-    assert!(!_input.to_string().is_empty());
-    "".parse().unwrap()
+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 emit_input(input: TokenStream) -> TokenStream {
-    input
+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/proc-macro/derive-helper-shadowed.rs

@@ -1,16 +1,16 @@
 // compile-pass
-// aux-build:derive-helper-shadowed.rs
+// aux-build:test-macros.rs
 // aux-build:derive-helper-shadowed-2.rs
 
 #[macro_use]
-extern crate derive_helper_shadowed;
-#[macro_use(my_attr)]
+extern crate test_macros;
+#[macro_use(empty_helper)]
 extern crate derive_helper_shadowed_2;
 
-macro_rules! my_attr { () => () }
+macro_rules! empty_helper { () => () }
 
-#[derive(MyTrait)]
-#[my_attr] // OK
+#[derive(Empty)]
+#[empty_helper] // OK
 struct S;
 
 fn main() {}

src/test/ui/proc-macro/derive-helper-shadowing.rs

@@ -1,23 +1,25 @@
-// aux-build:derive-helper-shadowing.rs
+// aux-build:test-macros.rs
 
-extern crate derive_helper_shadowing;
-use derive_helper_shadowing::*;
+#[macro_use]
+extern crate test_macros;
 
-#[my_attr] //~ ERROR `my_attr` is ambiguous
-#[derive(MyTrait)]
+use test_macros::empty_attr as empty_helper;
+
+#[empty_helper] //~ ERROR `empty_helper` is ambiguous
+#[derive(Empty)]
 struct S {
     // FIXME No ambiguity, attributes in non-macro positions are not resolved properly
-    #[my_attr]
+    #[empty_helper]
     field: [u8; {
         // FIXME No ambiguity, derive helpers are not put into scope for non-attributes
-        use my_attr;
+        use empty_helper;
 
         // FIXME No ambiguity, derive helpers are not put into scope for inner items
-        #[my_attr]
+        #[empty_helper]
         struct U;
 
         mod inner {
-            #[my_attr] //~ ERROR attribute `my_attr` is currently unknown
+            #[empty_helper] //~ ERROR attribute `empty_helper` is currently unknown
             struct V;
         }
 

src/test/ui/proc-macro/derive-helper-shadowing.stderr

@@ -1,29 +1,29 @@
-error[E0658]: The attribute `my_attr` is currently unknown to the compiler and may have meaning added to it in the future
-  --> $DIR/derive-helper-shadowing.rs:20:15
+error[E0658]: The attribute `empty_helper` is currently unknown to the compiler and may have meaning added to it in the future
+  --> $DIR/derive-helper-shadowing.rs:22:15
    |
-LL |             #[my_attr]
-   |               ^^^^^^^
+LL |             #[empty_helper]
+   |               ^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add #![feature(custom_attribute)] to the crate attributes to enable
 
-error[E0659]: `my_attr` is ambiguous (derive helper attribute vs any other name)
-  --> $DIR/derive-helper-shadowing.rs:6:3
+error[E0659]: `empty_helper` is ambiguous (derive helper attribute vs any other name)
+  --> $DIR/derive-helper-shadowing.rs:8:3
    |
-LL | #[my_attr]
-   |   ^^^^^^^ ambiguous name
+LL | #[empty_helper]
+   |   ^^^^^^^^^^^^ ambiguous name
    |
-note: `my_attr` could refer to the derive helper attribute defined here
-  --> $DIR/derive-helper-shadowing.rs:7:10
+note: `empty_helper` could refer to the derive helper attribute defined here
+  --> $DIR/derive-helper-shadowing.rs:9:10
    |
-LL | #[derive(MyTrait)]
-   |          ^^^^^^^
-note: `my_attr` could also refer to the attribute macro imported here
-  --> $DIR/derive-helper-shadowing.rs:4:5
+LL | #[derive(Empty)]
+   |          ^^^^^
+note: `empty_helper` could also refer to the attribute macro imported here
+  --> $DIR/derive-helper-shadowing.rs:6:5
    |
-LL | use derive_helper_shadowing::*;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = help: use `crate::my_attr` to refer to this attribute macro unambiguously
+LL | use test_macros::empty_attr as empty_helper;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = help: use `crate::empty_helper` to refer to this attribute macro unambiguously
 
 error: aborting due to 2 previous errors
 

src/test/ui/proc-macro/derive-in-mod.rs

@@ -0,0 +1,13 @@
+// compile-pass
+// aux-build:test-macros.rs
+
+extern crate test_macros;
+
+mod inner {
+    use test_macros::Empty;
+
+    #[derive(Empty)]
+    struct S;
+}
+
+fn main() {}

src/test/ui/proc-macro/derive-still-gated.rs

@@ -1,11 +1,9 @@
-// aux-build:derive-a.rs
-
-#![allow(warnings)]
+// aux-build:test-macros.rs
 
 #[macro_use]
-extern crate derive_a;
+extern crate test_macros;
 
-#[derive_A] //~ ERROR attribute `derive_A` is currently unknown
+#[derive_Empty] //~ ERROR attribute `derive_Empty` is currently unknown
 struct A;
 
 fn main() {}

src/test/ui/proc-macro/derive-still-gated.stderr

@@ -1,8 +1,8 @@
-error[E0658]: The attribute `derive_A` is currently unknown to the compiler and may have meaning added to it in the future
-  --> $DIR/derive-still-gated.rs:8:3
+error[E0658]: The attribute `derive_Empty` is currently unknown to the compiler and may have meaning added to it in the future
+  --> $DIR/derive-still-gated.rs:6:3
    |
-LL | #[derive_A]
-   |   ^^^^^^^^ help: a built-in attribute with a similar name exists: `derive`
+LL | #[derive_Empty]
+   |   ^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add #![feature(custom_attribute)] to the crate attributes to enable

src/test/ui/proc-macro/dollar-crate-issue-57089.rs

@@ -1,22 +1,23 @@
 // compile-pass
 // edition:2018
-// aux-build:dollar-crate.rs
+// aux-build:test-macros.rs
 
 // Anonymize unstable non-dummy spans while still showing dummy spans `0..0`.
 // normalize-stdout-test "bytes\([^0]\w*\.\.(\w+)\)" -> "bytes(LO..$1)"
 // normalize-stdout-test "bytes\((\w+)\.\.[^0]\w*\)" -> "bytes($1..HI)"
 
-extern crate dollar_crate;
+#[macro_use]
+extern crate test_macros;
 
 type S = u8;
 
 macro_rules! m {
     () => {
-        dollar_crate::m_empty! {
+        print_bang! {
             struct M($crate::S);
         }
 
-        #[dollar_crate::a]
+        #[print_attr]
         struct A($crate::S);
     };
 }

src/test/ui/proc-macro/dollar-crate-issue-57089.stdout

@@ -1,5 +1,5 @@
-PROC MACRO INPUT (PRETTY-PRINTED): struct M ( $crate :: S ) ;
-PROC MACRO INPUT: TokenStream [
+PRINT-BANG INPUT (DISPLAY): struct M ( $crate :: S ) ;
+PRINT-BANG INPUT (DEBUG): TokenStream [
     Ident {
         ident: "struct",
         span: #2 bytes(LO..HI),
@@ -38,8 +38,9 @@ PROC MACRO INPUT: TokenStream [
         span: #2 bytes(LO..HI),
     },
 ]
-ATTRIBUTE INPUT (PRETTY-PRINTED): struct A(crate::S);
-ATTRIBUTE INPUT: TokenStream [
+PRINT-ATTR INPUT (DISPLAY): struct A(crate::S);
+PRINT-ATTR RE-COLLECTED (DISPLAY): struct A ( $crate :: S ) ;
+PRINT-ATTR INPUT (DEBUG): TokenStream [
     Ident {
         ident: "struct",
         span: #2 bytes(LO..HI),

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

@@ -1,29 +1,28 @@
 // edition:2018
-// aux-build:dollar-crate.rs
+// aux-build:test-macros.rs
 // aux-build:dollar-crate-external.rs
 
 // Anonymize unstable non-dummy spans while still showing dummy spans `0..0`.
 // normalize-stdout-test "bytes\([^0]\w*\.\.(\w+)\)" -> "bytes(LO..$1)"
 // normalize-stdout-test "bytes\((\w+)\.\.[^0]\w*\)" -> "bytes($1..HI)"
 
-extern crate dollar_crate;
+#[macro_use]
+extern crate test_macros;
 extern crate dollar_crate_external;
 
 type S = u8;
 
 mod local {
-    use crate::dollar_crate;
-
     macro_rules! local {
         () => {
-            dollar_crate::m! {
+            print_bang! {
                 struct M($crate::S);
             }
 
-            #[dollar_crate::a]
+            #[print_attr]
             struct A($crate::S);
 
-            #[derive(dollar_crate::d)]
+            #[derive(Print)]
             struct D($crate::S); //~ ERROR the name `D` is defined multiple times
         };
     }

src/test/ui/proc-macro/dollar-crate.stderr

@@ -1,5 +1,5 @@
 error[E0428]: the name `D` is defined multiple times
-  --> $DIR/dollar-crate.rs:27:13
+  --> $DIR/dollar-crate.rs:26:13
    |
 LL |             struct D($crate::S);
    |             ^^^^^^^^^^^^^^^^^^^^
@@ -13,7 +13,7 @@ LL |     local!();
    = note: `D` must be defined only once in the type namespace of this module
 
 error[E0428]: the name `D` is defined multiple times
-  --> $DIR/dollar-crate.rs:37:5
+  --> $DIR/dollar-crate.rs:36:5
    |
 LL |     dollar_crate_external::external!();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/test/ui/proc-macro/dollar-crate.stdout

@@ -1,5 +1,5 @@
-PROC MACRO INPUT (PRETTY-PRINTED): struct M ( $crate :: S ) ;
-PROC MACRO INPUT: TokenStream [
+PRINT-BANG INPUT (DISPLAY): struct M ( $crate :: S ) ;
+PRINT-BANG INPUT (DEBUG): TokenStream [
     Ident {
         ident: "struct",
         span: #2 bytes(LO..HI),
@@ -38,8 +38,9 @@ PROC MACRO INPUT: TokenStream [
         span: #2 bytes(LO..HI),
     },
 ]
-ATTRIBUTE INPUT (PRETTY-PRINTED): struct A(crate::S);
-ATTRIBUTE INPUT: TokenStream [
+PRINT-ATTR INPUT (DISPLAY): struct A(crate::S);
+PRINT-ATTR RE-COLLECTED (DISPLAY): struct A ( $crate :: S ) ;
+PRINT-ATTR INPUT (DEBUG): TokenStream [
     Ident {
         ident: "struct",
         span: #2 bytes(LO..HI),
@@ -78,8 +79,9 @@ ATTRIBUTE INPUT: TokenStream [
         span: #2 bytes(LO..HI),
     },
 ]
-DERIVE INPUT (PRETTY-PRINTED): struct D(crate::S);
-DERIVE INPUT: TokenStream [
+PRINT-DERIVE INPUT (DISPLAY): struct D(crate::S);
+PRINT-DERIVE RE-COLLECTED (DISPLAY): struct D ( $crate :: S ) ;
+PRINT-DERIVE INPUT (DEBUG): TokenStream [
     Ident {
         ident: "struct",
         span: #2 bytes(LO..HI),
@@ -118,8 +120,8 @@ DERIVE INPUT: TokenStream [
         span: #2 bytes(LO..HI),
     },
 ]
-PROC MACRO INPUT (PRETTY-PRINTED): struct M ( $crate :: S ) ;
-PROC MACRO INPUT: TokenStream [
+PRINT-BANG INPUT (DISPLAY): struct M ( $crate :: S ) ;
+PRINT-BANG INPUT (DEBUG): TokenStream [
     Ident {
         ident: "struct",
         span: #10 bytes(LO..HI),
@@ -158,8 +160,9 @@ PROC MACRO INPUT: TokenStream [
         span: #10 bytes(LO..HI),
     },
 ]
-ATTRIBUTE INPUT (PRETTY-PRINTED): struct A(::dollar_crate_external::S);
-ATTRIBUTE INPUT: TokenStream [
+PRINT-ATTR INPUT (DISPLAY): struct A(::dollar_crate_external::S);
+PRINT-ATTR RE-COLLECTED (DISPLAY): struct A ( $crate :: S ) ;
+PRINT-ATTR INPUT (DEBUG): TokenStream [
     Ident {
         ident: "struct",
         span: #10 bytes(LO..HI),
@@ -198,8 +201,9 @@ ATTRIBUTE INPUT: TokenStream [
         span: #10 bytes(LO..HI),
     },
 ]
-DERIVE INPUT (PRETTY-PRINTED): struct D(::dollar_crate_external::S);
-DERIVE INPUT: TokenStream [
+PRINT-DERIVE INPUT (DISPLAY): struct D(::dollar_crate_external::S);
+PRINT-DERIVE RE-COLLECTED (DISPLAY): struct D ( $crate :: S ) ;
+PRINT-DERIVE INPUT (DEBUG): TokenStream [
     Ident {
         ident: "struct",
         span: #10 bytes(LO..HI),

src/test/ui/proc-macro/helper-attr-blocked-by-import-ambig.rs

@@ -0,0 +1,11 @@
+// aux-build:test-macros.rs
+
+#[macro_use(Empty)]
+extern crate test_macros;
+use test_macros::empty_attr as empty_helper;
+
+#[derive(Empty)]
+#[empty_helper] //~ ERROR `empty_helper` is ambiguous
+struct S;
+
+fn main() {}

src/test/ui/proc-macro/helper-attr-blocked-by-import-ambig.stderr

@@ -0,0 +1,21 @@
+error[E0659]: `empty_helper` is ambiguous (derive helper attribute vs any other name)
+  --> $DIR/helper-attr-blocked-by-import-ambig.rs:8:3
+   |
+LL | #[empty_helper]
+   |   ^^^^^^^^^^^^ ambiguous name
+   |
+note: `empty_helper` could refer to the derive helper attribute defined here
+  --> $DIR/helper-attr-blocked-by-import-ambig.rs:7:10
+   |
+LL | #[derive(Empty)]
+   |          ^^^^^
+note: `empty_helper` could also refer to the attribute macro imported here
+  --> $DIR/helper-attr-blocked-by-import-ambig.rs:5:5
+   |
+LL | use test_macros::empty_attr as empty_helper;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = help: use `crate::empty_helper` to refer to this attribute macro unambiguously
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0659`.

src/test/ui/proc-macro/helper-attr-blocked-by-import.rs

@@ -0,0 +1,28 @@
+// compile-pass
+// aux-build:test-macros.rs
+
+#[macro_use(Empty)]
+extern crate test_macros;
+
+use self::one::*;
+use self::two::*;
+
+mod empty_helper {}
+
+mod one {
+    use empty_helper;
+
+    #[derive(Empty)]
+    #[empty_helper]
+    struct One;
+}
+
+mod two {
+    use empty_helper;
+
+    #[derive(Empty)]
+    #[empty_helper]
+    struct Two;
+}
+
+fn main() {}

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

@@ -1,11 +1,8 @@
-// aux-build:derive-a.rs
+// aux-build:test-macros.rs
 
-#![allow(warnings)]
+extern crate test_macros;
 
-#[macro_use]
-extern crate derive_a;
-
-use derive_a::derive_a;
-//~^ ERROR: unresolved import `derive_a::derive_a`
+use test_macros::empty_derive;
+//~^ ERROR: unresolved import `test_macros::empty_derive`
 
 fn main() {}

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

@@ -1,8 +1,8 @@
-error[E0432]: unresolved import `derive_a::derive_a`
-  --> $DIR/import.rs:8:5
+error[E0432]: unresolved import `test_macros::empty_derive`
+  --> $DIR/import.rs:5:5
    |
-LL | use derive_a::derive_a;
-   |     ^^^^^^^^^^^^^^^^^^ no `derive_a` in the root
+LL | use test_macros::empty_derive;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ no `empty_derive` in the root
 
 error: aborting due to previous error
 

src/test/ui/proc-macro/issue-36935.rs

@@ -0,0 +1,12 @@
+// aux-build:test-macros.rs
+
+#[macro_use]
+extern crate test_macros;
+
+#[derive(Identity, Panic)] //~ ERROR proc-macro derive panicked
+struct Baz {
+    a: i32,
+    b: i32,
+}
+
+fn main() {}

src/test/ui/proc-macro/issue-36935.stderr

@@ -0,0 +1,10 @@
+error: proc-macro derive panicked
+  --> $DIR/issue-36935.rs:6:20
+   |
+LL | #[derive(Identity, Panic)]
+   |                    ^^^^^
+   |
+   = help: message: panic-derive
+
+error: aborting due to previous error
+

src/test/ui/proc-macro/issue-37788.rs

@@ -1,7 +1,7 @@
-// aux-build:derive-a-b.rs
+// aux-build:test-macros.rs
 
 #[macro_use]
-extern crate derive_a_b;
+extern crate test_macros;
 
 fn main() {
     // Test that constructing the `visible_parent_map` (in `cstore_impl.rs`) does not ICE.

src/test/ui/proc-macro/issue-41211.rs

@@ -1,14 +1,14 @@
-// aux-build:issue-41211.rs
+// aux-build:test-macros.rs
 
 // FIXME: https://github.com/rust-lang/rust/issues/41430
 // This is a temporary regression test for the ICE reported in #41211
 
 #![feature(custom_inner_attributes)]
 
-#![emit_unchanged]
-//~^ ERROR attribute `emit_unchanged` is currently unknown to the compiler
+#![identity_attr]
+//~^ ERROR attribute `identity_attr` is currently unknown to the compiler
 //~| ERROR inconsistent resolution for a macro: first custom attribute, then attribute macro
-extern crate issue_41211;
-use issue_41211::emit_unchanged;
+extern crate test_macros;
+use test_macros::identity_attr;
 
 fn main() {}

src/test/ui/proc-macro/issue-41211.stderr

@@ -1,8 +1,8 @@
-error[E0658]: The attribute `emit_unchanged` is currently unknown to the compiler and may have meaning added to it in the future
+error[E0658]: The attribute `identity_attr` is currently unknown to the compiler and may have meaning added to it in the future
   --> $DIR/issue-41211.rs:8:4
    |
-LL | #![emit_unchanged]
-   |    ^^^^^^^^^^^^^^
+LL | #![identity_attr]
+   |    ^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add #![feature(custom_attribute)] to the crate attributes to enable
@@ -10,8 +10,8 @@ LL | #![emit_unchanged]
 error: inconsistent resolution for a macro: first custom attribute, then attribute macro
   --> $DIR/issue-41211.rs:8:4
    |
-LL | #![emit_unchanged]
-   |    ^^^^^^^^^^^^^^
+LL | #![identity_attr]
+   |    ^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 

src/test/ui/proc-macro/issue-53481.rs

@@ -1,21 +1,21 @@
 // compile-pass
-// aux-build:issue-53481.rs
+// aux-build:test-macros.rs
 
 #[macro_use]
-extern crate issue_53481;
+extern crate test_macros;
 
 mod m1 {
-    use m2::MyTrait;
+    use m2::Empty;
 
-    #[derive(MyTrait)]
+    #[derive(Empty)]
     struct A {}
 }
 
 mod m2 {
-    pub type MyTrait = u8;
+    pub type Empty = u8;
 
-    #[derive(MyTrait)]
-    #[my_attr]
+    #[derive(Empty)]
+    #[empty_helper]
     struct B {}
 }
 

src/test/ui/proc-macro/load-panic.rs

@@ -1,10 +1,9 @@
-// aux-build:derive-panic.rs
-// compile-flags:--error-format human
+// aux-build:test-macros.rs
 
 #[macro_use]
-extern crate derive_panic;
+extern crate test_macros;
 
-#[derive(A)]
+#[derive(Panic)]
 //~^ ERROR: proc-macro derive panicked
 struct Foo;
 

src/test/ui/proc-macro/load-panic.stderr

@@ -1,10 +1,10 @@
 error: proc-macro derive panicked
-  --> $DIR/load-panic.rs:7:10
+  --> $DIR/load-panic.rs:6:10
    |
-LL | #[derive(A)]
-   |          ^
+LL | #[derive(Panic)]
+   |          ^^^^^
    |
-   = help: message: nope!
+   = help: message: panic-derive
 
 error: aborting due to previous error
 

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

@@ -1,13 +1,13 @@
-// aux-build:macro-brackets.rs
+// aux-build:test-macros.rs
 
-extern crate macro_brackets as bar;
-use bar::doit;
+#[macro_use]
+extern crate test_macros;
 
 macro_rules! id {
     ($($t:tt)*) => ($($t)*)
 }
 
-#[doit]
+#[identity_attr]
 id![static X: u32 = 'a';]; //~ ERROR: mismatched types
 
 

src/test/ui/proc-macro/macro-use-attr.rs

@@ -1,9 +1,10 @@
 // compile-pass
-// aux-build:attr_proc_macro.rs
+// aux-build:test-macros.rs
 
-#[macro_use] extern crate attr_proc_macro;
+#[macro_use]
+extern crate test_macros;
 
-#[attr_proc_macro]
+#[identity_attr]
 struct Foo;
 
 fn main() {

src/test/ui/proc-macro/macro-use-bang.rs

@@ -1,11 +1,11 @@
 // compile-pass
-// aux-build:bang_proc_macro.rs
+// aux-build:test-macros.rs
 
 #![feature(proc_macro_hygiene)]
 
 #[macro_use]
-extern crate bang_proc_macro;
+extern crate test_macros;
 
 fn main() {
-    bang_proc_macro!(println!("Hello, world!"));
+    identity!(println!("Hello, world!"));
 }

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

@@ -1,10 +1,9 @@
 // aux-build:test-macros.rs
 // ignore-wasm32
 
+#[macro_use]
 extern crate test_macros;
 
-use test_macros::{nop_attr, no_output, emit_input};
-
 fn main() {
     assert_eq!(unsafe { rust_get_test_int() }, 0isize);
     assert_eq!(unsafe { rust_dbg_extern_identity_u32(0xDEADBEEF) }, 0xDEADBEEF);
@@ -12,14 +11,14 @@ fn main() {
 
 #[link(name = "rust_test_helpers", kind = "static")]
 extern {
-    #[no_output]
+    #[empty_attr]
     //~^ ERROR macro invocations in `extern {}` blocks are experimental
     fn some_definitely_unknown_symbol_which_should_be_removed();
 
-    #[nop_attr]
+    #[identity_attr]
     //~^ ERROR macro invocations in `extern {}` blocks are experimental
     fn rust_get_test_int() -> isize;
 
-    emit_input!(fn rust_dbg_extern_identity_u32(arg: u32) -> u32;);
+    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-extern.stderr

@@ -1,26 +1,26 @@
 error[E0658]: macro invocations in `extern {}` blocks are experimental
-  --> $DIR/macros-in-extern.rs:15:5
+  --> $DIR/macros-in-extern.rs:14:5
    |
-LL |     #[no_output]
-   |     ^^^^^^^^^^^^
+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:19:5
+  --> $DIR/macros-in-extern.rs:18:5
    |
-LL |     #[nop_attr]
-   |     ^^^^^^^^^^^
+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:23:5
+  --> $DIR/macros-in-extern.rs:22:5
    |
-LL |     emit_input!(fn rust_dbg_extern_identity_u32(arg: u32) -> u32;);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+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

src/test/ui/proc-macro/nested-item-spans.rs

@@ -1,10 +1,9 @@
-// aux-build:nested-item-spans.rs
+// aux-build:test-macros.rs
 
-extern crate nested_item_spans;
+#[macro_use]
+extern crate test_macros;
 
-use nested_item_spans::foo;
-
-#[foo]
+#[recollect_attr]
 fn another() {
     fn bar() {
         let x: u32 = "x"; //~ ERROR: mismatched types
@@ -14,7 +13,7 @@ fn another() {
 }
 
 fn main() {
-    #[foo]
+    #[recollect_attr]
     fn bar() {
         let x: u32 = "x"; //~ ERROR: mismatched types
     }

src/test/ui/proc-macro/nested-item-spans.stderr

@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/nested-item-spans.rs:10:22
+  --> $DIR/nested-item-spans.rs:9:22
    |
 LL |         let x: u32 = "x";
    |                      ^^^ expected u32, found reference
@@ -8,7 +8,7 @@ LL |         let x: u32 = "x";
               found type `&'static str`
 
 error[E0308]: mismatched types
-  --> $DIR/nested-item-spans.rs:19:22
+  --> $DIR/nested-item-spans.rs:18:22
    |
 LL |         let x: u32 = "x";
    |                      ^^^ expected u32, found reference

src/test/ui/proc-macro/no-macro-use-attr.rs

@@ -1,9 +1,9 @@
-// aux-build:derive-a.rs
+// aux-build:test-macros.rs
 
 #![feature(rustc_attrs)]
 #![warn(unused_extern_crates)]
 
-extern crate derive_a;
+extern crate test_macros;
 //~^ WARN unused extern crate
 
 #[rustc_error]

src/test/ui/proc-macro/no-macro-use-attr.stderr

@@ -1,8 +1,8 @@
 warning: unused extern crate
   --> $DIR/no-macro-use-attr.rs:6:1
    |
-LL | extern crate derive_a;
-   | ^^^^^^^^^^^^^^^^^^^^^^ help: remove it
+LL | extern crate test_macros;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
    |
 note: lint level defined here
   --> $DIR/no-macro-use-attr.rs:4:9

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

@@ -1,61 +1,62 @@
-// aux-build:proc-macro-gates.rs
+// aux-build:test-macros.rs
 // gate-test-proc_macro_hygiene
 
 #![feature(stmt_expr_attributes)]
 
-extern crate proc_macro_gates as foo;
-
-use foo::*;
+#[macro_use]
+extern crate test_macros;
 
 fn _test_inner() {
-    #![a] //~ ERROR: non-builtin inner attributes are unstable
+    #![empty_attr] //~ ERROR: non-builtin inner attributes are unstable
 }
 
-#[a] //~ ERROR: custom attributes cannot be applied to modules
+#[empty_attr] //~ ERROR: custom attributes cannot be applied to modules
 mod _test2 {}
 
 mod _test2_inner {
-    #![a] //~ ERROR: custom attributes cannot be applied to modules
+    #![empty_attr] //~ ERROR: custom attributes cannot be applied to modules
           //~| ERROR: non-builtin inner attributes are unstable
 }
 
-#[a = "y"] //~ ERROR: must only be followed by a delimiter token
+#[empty_attr = "y"] //~ ERROR: must only be followed by a delimiter token
 fn _test3() {}
 
 fn attrs() {
     // Statement, item
-    #[a] // OK
+    #[empty_attr] // OK
     struct S;
 
     // Statement, macro
-    #[a] //~ ERROR: custom attributes cannot be applied to statements
+    #[empty_attr] //~ ERROR: custom attributes cannot be applied to statements
     println!();
 
     // Statement, semi
-    #[a] //~ ERROR: custom attributes cannot be applied to statements
+    #[empty_attr] //~ ERROR: custom attributes cannot be applied to statements
     S;
 
     // Statement, local
-    #[a] //~ ERROR: custom attributes cannot be applied to statements
+    #[empty_attr] //~ ERROR: custom attributes cannot be applied to statements
     let _x = 2;
 
     // Expr
-    let _x = #[a] 2; //~ ERROR: custom attributes cannot be applied to expressions
+    let _x = #[identity_attr] 2; //~ ERROR: custom attributes cannot be applied to expressions
 
     // Opt expr
-    let _x = [#[a] 2]; //~ ERROR: custom attributes cannot be applied to expressions
+    let _x = [#[identity_attr] 2]; //~ ERROR: custom attributes cannot be applied to expressions
 
     // Expr macro
-    let _x = #[a] println!(); //~ ERROR: custom attributes cannot be applied to expressions
+    let _x = #[identity_attr] println!();
+    //~^ ERROR: custom attributes cannot be applied to expressions
 }
 
 fn main() {
-    let _x: m!(u32) = 3; //~ ERROR: procedural macros cannot be expanded to types
-    if let m!(Some(_x)) = Some(3) {} //~ ERROR: procedural macros cannot be expanded to patterns
+    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
 
-    m!(struct S;); //~ ERROR: procedural macros cannot be expanded to statements
-    m!(let _x = 3;); //~ ERROR: procedural macros cannot be expanded to statements
+    empty!(struct S;); //~ ERROR: procedural macros cannot be expanded to statements
+    empty!(let _x = 3;); //~ ERROR: procedural macros cannot be expanded to statements
 
-    let _x = m!(3); //~ ERROR: procedural macros cannot be expanded to expressions
-    let _x = [m!(3)]; //~ ERROR: procedural macros cannot be expanded to expressions
+    let _x = identity!(3); //~ ERROR: procedural macros cannot be expanded to expressions
+    let _x = [empty!(3)]; //~ ERROR: procedural macros cannot be expanded to expressions
 }

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

@@ -1,95 +1,95 @@
 error[E0658]: non-builtin inner attributes are unstable
-  --> $DIR/proc-macro-gates.rs:11:5
+  --> $DIR/proc-macro-gates.rs:10:5
    |
-LL |     #![a]
-   |     ^^^^^
+LL |     #![empty_attr]
+   |     ^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/54726
    = help: add #![feature(custom_inner_attributes)] to the crate attributes to enable
 
 error[E0658]: non-builtin inner attributes are unstable
-  --> $DIR/proc-macro-gates.rs:18:5
+  --> $DIR/proc-macro-gates.rs:17:5
    |
-LL |     #![a]
-   |     ^^^^^
+LL |     #![empty_attr]
+   |     ^^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/54726
    = help: add #![feature(custom_inner_attributes)] to the crate attributes to enable
 
 error[E0658]: custom attributes cannot be applied to modules
-  --> $DIR/proc-macro-gates.rs:14:1
+  --> $DIR/proc-macro-gates.rs:13:1
    |
-LL | #[a]
-   | ^^^^
+LL | #[empty_attr]
+   | ^^^^^^^^^^^^^
    |
    = 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]: custom attributes cannot be applied to modules
-  --> $DIR/proc-macro-gates.rs:18:5
+  --> $DIR/proc-macro-gates.rs:17:5
    |
-LL |     #![a]
-   |     ^^^^^
+LL |     #![empty_attr]
+   |     ^^^^^^^^^^^^^^
    |
    = 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: custom attribute invocations must be of the form #[foo] or #[foo(..)], the macro name must only be followed by a delimiter token
-  --> $DIR/proc-macro-gates.rs:22:1
+  --> $DIR/proc-macro-gates.rs:21:1
    |
-LL | #[a = "y"]
-   | ^^^^^^^^^^
+LL | #[empty_attr = "y"]
+   | ^^^^^^^^^^^^^^^^^^^
 
 error[E0658]: custom attributes cannot be applied to statements
-  --> $DIR/proc-macro-gates.rs:31:5
+  --> $DIR/proc-macro-gates.rs:30:5
    |
-LL |     #[a]
-   |     ^^^^
+LL |     #[empty_attr]
+   |     ^^^^^^^^^^^^^
    |
    = 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]: custom attributes cannot be applied to statements
-  --> $DIR/proc-macro-gates.rs:35:5
+  --> $DIR/proc-macro-gates.rs:34:5
    |
-LL |     #[a]
-   |     ^^^^
+LL |     #[empty_attr]
+   |     ^^^^^^^^^^^^^
    |
    = 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]: custom attributes cannot be applied to statements
-  --> $DIR/proc-macro-gates.rs:39:5
+  --> $DIR/proc-macro-gates.rs:38:5
    |
-LL |     #[a]
-   |     ^^^^
+LL |     #[empty_attr]
+   |     ^^^^^^^^^^^^^
    |
    = 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]: custom attributes cannot be applied to expressions
-  --> $DIR/proc-macro-gates.rs:43:14
+  --> $DIR/proc-macro-gates.rs:42:14
    |
-LL |     let _x = #[a] 2;
-   |              ^^^^
+LL |     let _x = #[identity_attr] 2;
+   |              ^^^^^^^^^^^^^^^^
    |
    = 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]: custom attributes cannot be applied to expressions
-  --> $DIR/proc-macro-gates.rs:46:15
+  --> $DIR/proc-macro-gates.rs:45:15
    |
-LL |     let _x = [#[a] 2];
-   |               ^^^^
+LL |     let _x = [#[identity_attr] 2];
+   |               ^^^^^^^^^^^^^^^^
    |
    = 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]: custom attributes cannot be applied to expressions
-  --> $DIR/proc-macro-gates.rs:49:14
+  --> $DIR/proc-macro-gates.rs:48:14
    |
-LL |     let _x = #[a] println!();
-   |              ^^^^
+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
@@ -97,8 +97,8 @@ LL |     let _x = #[a] println!();
 error[E0658]: procedural macros cannot be expanded to types
   --> $DIR/proc-macro-gates.rs:53:13
    |
-LL |     let _x: m!(u32) = 3;
-   |             ^^^^^^^
+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
@@ -106,17 +106,8 @@ LL |     let _x: m!(u32) = 3;
 error[E0658]: procedural macros cannot be expanded to patterns
   --> $DIR/proc-macro-gates.rs:54:12
    |
-LL |     if let m!(Some(_x)) = Some(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 statements
-  --> $DIR/proc-macro-gates.rs:56:5
-   |
-LL |     m!(struct S;);
-   |     ^^^^^^^^^^^^^^
+LL |     if let identity!(Some(_x)) = Some(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
@@ -124,26 +115,35 @@ LL |     m!(struct S;);
 error[E0658]: procedural macros cannot be expanded to statements
   --> $DIR/proc-macro-gates.rs:57:5
    |
-LL |     m!(let _x = 3;);
-   |     ^^^^^^^^^^^^^^^^
+LL |     empty!(struct S;);
+   |     ^^^^^^^^^^^^^^^^^^
+   |
+   = 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 statements
+  --> $DIR/proc-macro-gates.rs:58:5
+   |
+LL |     empty!(let _x = 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 expressions
-  --> $DIR/proc-macro-gates.rs:59:14
+  --> $DIR/proc-macro-gates.rs:60:14
    |
-LL |     let _x = m!(3);
-   |              ^^^^^
+LL |     let _x = identity!(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 expressions
-  --> $DIR/proc-macro-gates.rs:60:15
+  --> $DIR/proc-macro-gates.rs:61:15
    |
-LL |     let _x = [m!(3)];
-   |               ^^^^^
+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

src/test/ui/proc-macro/proc-macro-gates2.rs

@@ -1,21 +1,20 @@
-// aux-build:proc-macro-gates.rs
+// aux-build:test-macros.rs
 
 #![feature(stmt_expr_attributes)]
 
-extern crate proc_macro_gates as foo;
-
-use foo::*;
+#[macro_use]
+extern crate test_macros;
 
 // NB. these errors aren't the best errors right now, but they're definitely
 // intended to be errors. Somehow using a custom attribute in these positions
 // should either require a feature gate or not be allowed on stable.
 
-fn _test6<#[a] T>() {}
+fn _test6<#[empty_attr] T>() {}
 //~^ ERROR: unknown to the compiler
 
 fn _test7() {
     match 1 {
-        #[a] //~ ERROR: unknown to the compiler
+        #[empty_attr] //~ ERROR: unknown to the compiler
         0 => {}
         _ => {}
     }

src/test/ui/proc-macro/proc-macro-gates2.stderr

@@ -1,17 +1,17 @@
-error[E0658]: The attribute `a` is currently unknown to the compiler and may have meaning added to it in the future
-  --> $DIR/proc-macro-gates2.rs:13:11
+error[E0658]: The attribute `empty_attr` is currently unknown to the compiler and may have meaning added to it in the future
+  --> $DIR/proc-macro-gates2.rs:12:11
    |
-LL | fn _test6<#[a] T>() {}
-   |           ^^^^
+LL | fn _test6<#[empty_attr] T>() {}
+   |           ^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add #![feature(custom_attribute)] to the crate attributes to enable
 
-error[E0658]: The attribute `a` is currently unknown to the compiler and may have meaning added to it in the future
-  --> $DIR/proc-macro-gates2.rs:18:9
+error[E0658]: The attribute `empty_attr` is currently unknown to the compiler and may have meaning added to it in the future
+  --> $DIR/proc-macro-gates2.rs:17:9
    |
-LL |         #[a]
-   |         ^^^^
+LL |         #[empty_attr]
+   |         ^^^^^^^^^^^^^
    |
    = note: for more information, see https://github.com/rust-lang/rust/issues/29642
    = help: add #![feature(custom_attribute)] to the crate attributes to enable

src/test/ui/proc-macro/resolve-error.rs

@@ -1,7 +1,6 @@
 // aux-build:derive-foo.rs
 // aux-build:derive-clona.rs
-// aux-build:attr_proc_macro.rs
-// aux-build:bang_proc_macro.rs
+// aux-build:test-macros.rs
 
 #![feature(custom_attribute)]
 
@@ -9,11 +8,10 @@
 extern crate derive_foo;
 #[macro_use]
 extern crate derive_clona;
-extern crate attr_proc_macro;
-extern crate bang_proc_macro;
+extern crate test_macros;
 
-use attr_proc_macro::attr_proc_macro;
-use bang_proc_macro::bang_proc_macro;
+use test_macros::empty as bang_proc_macro;
+use test_macros::empty_attr as attr_proc_macro;
 
 macro_rules! FooWithLongNam {
     () => {}

src/test/ui/proc-macro/resolve-error.stderr

@@ -1,47 +1,47 @@
 error: cannot find derive macro `FooWithLongNan` in this scope
-  --> $DIR/resolve-error.rs:26:10
+  --> $DIR/resolve-error.rs:24:10
    |
 LL | #[derive(FooWithLongNan)]
    |          ^^^^^^^^^^^^^^ help: try: `FooWithLongName`
 
 error: cannot find derive macro `Dlone` in this scope
-  --> $DIR/resolve-error.rs:36:10
+  --> $DIR/resolve-error.rs:34:10
    |
 LL | #[derive(Dlone)]
    |          ^^^^^ help: try: `Clone`
 
 error: cannot find derive macro `Dlona` in this scope
-  --> $DIR/resolve-error.rs:40:10
+  --> $DIR/resolve-error.rs:38:10
    |
 LL | #[derive(Dlona)]
    |          ^^^^^ help: try: `Clona`
 
 error: cannot find derive macro `attr_proc_macra` in this scope
-  --> $DIR/resolve-error.rs:44:10
+  --> $DIR/resolve-error.rs:42:10
    |
 LL | #[derive(attr_proc_macra)]
    |          ^^^^^^^^^^^^^^^
 
 error: cannot find macro `FooWithLongNama!` in this scope
-  --> $DIR/resolve-error.rs:49:5
+  --> $DIR/resolve-error.rs:47:5
    |
 LL |     FooWithLongNama!();
    |     ^^^^^^^^^^^^^^^ help: you could try the macro: `FooWithLongNam`
 
 error: cannot find macro `attr_proc_macra!` in this scope
-  --> $DIR/resolve-error.rs:52:5
+  --> $DIR/resolve-error.rs:50:5
    |
 LL |     attr_proc_macra!();
    |     ^^^^^^^^^^^^^^^ help: you could try the macro: `attr_proc_mac`
 
 error: cannot find macro `Dlona!` in this scope
-  --> $DIR/resolve-error.rs:55:5
+  --> $DIR/resolve-error.rs:53:5
    |
 LL |     Dlona!();
    |     ^^^^^
 
 error: cannot find macro `bang_proc_macrp!` in this scope
-  --> $DIR/resolve-error.rs:58:5
+  --> $DIR/resolve-error.rs:56:5
    |
 LL |     bang_proc_macrp!();
    |     ^^^^^^^^^^^^^^^ help: you could try the macro: `bang_proc_macro`

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

@@ -1,8 +1,8 @@
-// aux-build:derive-a.rs
+// aux-build:test-macros.rs
 
 #[macro_use]
-extern crate derive_a;
+extern crate test_macros;
 #[macro_use]
-extern crate derive_a; //~ ERROR the name `derive_a` is defined multiple times
+extern crate test_macros; //~ ERROR the name `test_macros` is defined multiple times
 
 fn main() {}

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

@@ -1,13 +1,13 @@
-error[E0259]: the name `derive_a` is defined multiple times
+error[E0259]: the name `test_macros` is defined multiple times
   --> $DIR/shadow.rs:6:1
    |
-LL | extern crate derive_a;
-   | ---------------------- previous import of the extern crate `derive_a` here
+LL | extern crate test_macros;
+   | ------------------------- previous import of the extern crate `test_macros` here
 LL | #[macro_use]
-LL | extern crate derive_a;
-   | ^^^^^^^^^^^^^^^^^^^^^^ `derive_a` reimported here
+LL | extern crate test_macros;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^ `test_macros` reimported here
    |
-   = note: `derive_a` must be defined only once in the type namespace of this module
+   = note: `test_macros` must be defined only once in the type namespace of this module
 
 error: aborting due to previous error
 

src/test/ui/proc-macro/span-preservation.rs

@@ -1,19 +1,18 @@
 //~ ERROR mismatched types
-// aux-build:span-preservation.rs
+// aux-build:test-macros.rs
 
 // For each of these, we should get the appropriate type mismatch error message,
 // and the function should be echoed.
 
-extern crate span_preservation as foo;
+#[macro_use]
+extern crate test_macros;
 
-use foo::foo;
-
-#[foo]
+#[recollect_attr]
 fn a() {
     let x: usize = "hello";;;;; //~ ERROR mismatched types
 }
 
-#[foo]
+#[recollect_attr]
 fn b(x: Option<isize>) -> usize {
     match x {
         Some(x) => { return x }, //~ ERROR mismatched types
@@ -21,7 +20,7 @@ fn b(x: Option<isize>) -> usize {
     }
 }
 
-#[foo]
+#[recollect_attr]
 fn c() {
     struct Foo {
         a: usize
@@ -39,12 +38,12 @@ fn c() {
 // FIXME: This doesn't work at the moment. See the one below. The pretty-printer
 // injects a "C" between `extern` and `fn` which causes a "probably_eq"
 // `TokenStream` mismatch. The lack of `"C"` should be preserved in the AST.
-#[foo]
+#[recollect_attr]
 extern fn bar() {
     0
 }
 
-#[foo]
+#[recollect_attr]
 extern "C" fn baz() {
     0 //~ ERROR mismatched types
 }

src/test/ui/proc-macro/span-preservation.stderr

@@ -4,7 +4,7 @@ error[E0308]: mismatched types
               found type `{integer}`
 
 error[E0308]: mismatched types
-  --> $DIR/span-preservation.rs:13:20
+  --> $DIR/span-preservation.rs:12:20
    |
 LL |     let x: usize = "hello";;;;;
    |                    ^^^^^^^ expected usize, found reference
@@ -13,7 +13,7 @@ LL |     let x: usize = "hello";;;;;
               found type `&'static str`
 
 error[E0308]: mismatched types
-  --> $DIR/span-preservation.rs:19:29
+  --> $DIR/span-preservation.rs:18:29
    |
 LL | fn b(x: Option<isize>) -> usize {
    |                           ----- expected `usize` because of return type
@@ -22,13 +22,13 @@ LL |         Some(x) => { return x },
    |                             ^ expected usize, found isize
 
 error[E0308]: mismatched types
-  --> $DIR/span-preservation.rs:35:22
+  --> $DIR/span-preservation.rs:34:22
    |
 LL |     let x = Foo { a: 10isize };
    |                      ^^^^^^^ expected usize, found isize
 
 error[E0560]: struct `c::Foo` has no field named `b`
-  --> $DIR/span-preservation.rs:36:26
+  --> $DIR/span-preservation.rs:35:26
    |
 LL |     let y = Foo { a: 10, b: 10isize };
    |                          ^ `c::Foo` does not have this field
@@ -36,7 +36,7 @@ LL |     let y = Foo { a: 10, b: 10isize };
    = note: available fields are: `a`
 
 error[E0308]: mismatched types
-  --> $DIR/span-preservation.rs:49:5
+  --> $DIR/span-preservation.rs:48:5
    |
 LL | extern "C" fn baz() {
    |                     - possibly return type missing here?