expand/resolve: Turn #[derive] into a regular macro attribute

src/rustdoc-json-types/lib.rs

@@ -96,8 +96,8 @@ pub struct Deprecation {
     pub note: Option<String>,
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum Visibility {
     Public,
     /// For the most part items are private by default. The exceptions are associated items of
@@ -112,8 +112,8 @@ pub enum Visibility {
     },
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum GenericArgs {
     /// <'a, 32, B: Copy, C = u32>
     AngleBracketed { args: Vec<GenericArg>, bindings: Vec<TypeBinding> },
@@ -121,8 +121,8 @@ pub enum GenericArgs {
     Parenthesized { inputs: Vec<Type>, output: Option<Type> },
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum GenericArg {
     Lifetime(String),
     Type(Type),
@@ -144,8 +144,8 @@ pub struct TypeBinding {
     pub binding: TypeBindingKind,
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum TypeBindingKind {
     Equality(Type),
     Constraint(Vec<GenericBound>),
@@ -154,8 +154,8 @@ pub enum TypeBindingKind {
 #[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
 pub struct Id(pub String);
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum ItemKind {
     Module,
     ExternCrate,
@@ -184,8 +184,8 @@ pub enum ItemKind {
     Keyword,
 }
 
-#[serde(untagged)]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(untagged)]
 pub enum ItemEnum {
     ModuleItem(Module),
     ExternCrateItem {
@@ -264,17 +264,17 @@ pub struct Enum {
     pub impls: Vec<Id>,
 }
 
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
 #[serde(rename_all = "snake_case")]
 #[serde(tag = "variant_kind", content = "variant_inner")]
-#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
 pub enum Variant {
     Plain,
     Tuple(Vec<Type>),
     Struct(Vec<Id>),
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum StructType {
     Plain,
     Tuple,
@@ -310,24 +310,24 @@ pub struct GenericParamDef {
     pub kind: GenericParamDefKind,
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum GenericParamDefKind {
     Lifetime,
     Type { bounds: Vec<GenericBound>, default: Option<Type> },
     Const(Type),
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum WherePredicate {
     BoundPredicate { ty: Type, bounds: Vec<GenericBound> },
     RegionPredicate { lifetime: String, bounds: Vec<GenericBound> },
     EqPredicate { lhs: Type, rhs: Type },
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum GenericBound {
     TraitBound {
         #[serde(rename = "trait")]
@@ -339,17 +339,17 @@ pub enum GenericBound {
     Outlives(String),
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum TraitBoundModifier {
     None,
     Maybe,
     MaybeConst,
 }
 
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
 #[serde(rename_all = "snake_case")]
 #[serde(tag = "kind", content = "inner")]
-#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
 pub enum Type {
     /// Structs, enums, and traits
     ResolvedPath {
@@ -448,8 +448,8 @@ pub struct Impl {
     pub blanket_impl: Option<Type>,
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub struct Import {
     /// The full path being imported.
     pub span: String,
@@ -468,8 +468,8 @@ pub struct ProcMacro {
     pub helpers: Vec<String>,
 }
 
-#[serde(rename_all = "snake_case")]
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+#[serde(rename_all = "snake_case")]
 pub enum MacroKind {
     /// A bang macro `foo!()`.
     Bang,

src/test/run-make-fulldeps/simd-ffi/simd.rs

@@ -75,3 +75,8 @@ auto trait Freeze {}
 macro_rules! Copy {
     () => {};
 }
+#[macro_export]
+#[rustc_builtin_macro]
+macro_rules! derive {
+    () => {};
+}

src/test/ui/derives/derive-deadlock.rs

@@ -0,0 +1,6 @@
+use std as derive;
+
+#[derive(Default)] //~ ERROR cannot determine resolution for the attribute macro `derive`
+struct S;
+
+fn main() {}

src/test/ui/derives/derive-deadlock.stderr

@@ -0,0 +1,10 @@
+error: cannot determine resolution for the attribute macro `derive`
+  --> $DIR/derive-deadlock.rs:3:3
+   |
+LL | #[derive(Default)]
+   |   ^^^^^^
+   |
+   = note: import resolution is stuck, try simplifying macro imports
+
+error: aborting due to previous error
+

src/test/ui/derives/derive-multiple-with-packed.rs

@@ -0,0 +1,10 @@
+// check-pass
+
+#[derive(Clone, Copy)]
+#[derive(Debug)] // OK, even if `Copy` is in the different `#[derive]`
+#[repr(packed)]
+struct CacheRecordHeader {
+    field: u64,
+}
+
+fn main() {}

src/test/ui/derives/deriving-meta-empty-trait-list.rs

@@ -1,6 +1,8 @@
+// check-pass
+
 #![deny(unused)]
 
-#[derive()] //~ ERROR unused attribute
+#[derive()] // OK
 struct _Bar;
 
 pub fn main() {}

src/test/ui/derives/deriving-meta-empty-trait-list.stderr

@@ -1,15 +0,0 @@
-error: unused attribute
-  --> $DIR/deriving-meta-empty-trait-list.rs:3:1
-   |
-LL | #[derive()]
-   | ^^^^^^^^^^^
-   |
-note: the lint level is defined here
-  --> $DIR/deriving-meta-empty-trait-list.rs:1:9
-   |
-LL | #![deny(unused)]
-   |         ^^^^^^
-   = note: `#[deny(unused_attributes)]` implied by `#[deny(unused)]`
-
-error: aborting due to previous error
-

src/test/ui/derives/issue-36617.rs

@@ -1,4 +1,3 @@
-#![derive(Copy)] //~ ERROR `derive` may only be applied to structs, enums and unions
-                 //~| ERROR cannot determine resolution for the derive macro `Copy`
+#![derive(Copy)] //~ ERROR cannot determine resolution for the attribute macro `derive`
 
 fn main() {}

src/test/ui/derives/issue-36617.stderr

@@ -1,17 +1,10 @@
-error[E0774]: `derive` may only be applied to structs, enums and unions
-  --> $DIR/issue-36617.rs:1:1
+error: cannot determine resolution for the attribute macro `derive`
+  --> $DIR/issue-36617.rs:1:4
    |
 LL | #![derive(Copy)]
-   | ^^^^^^^^^^^^^^^^ help: try an outer attribute: `#[derive(Copy)]`
-
-error: cannot determine resolution for the derive macro `Copy`
-  --> $DIR/issue-36617.rs:1:11
-   |
-LL | #![derive(Copy)]
-   |           ^^^^
+   |    ^^^^^^
    |
    = note: import resolution is stuck, try simplifying macro imports
 
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0774`.

src/test/ui/feature-gates/issue-43106-gating-of-derive.rs

@@ -6,6 +6,7 @@
 mod derive {
     mod inner { #![derive(Debug)] }
     //~^ ERROR `derive` may only be applied to structs, enums and unions
+    //~| ERROR inner macro attributes are unstable
 
     #[derive(Debug)]
     //~^ ERROR `derive` may only be applied to structs, enums and unions

src/test/ui/feature-gates/issue-43106-gating-of-derive.stderr

@@ -4,30 +4,40 @@ error[E0774]: `derive` may only be applied to structs, enums and unions
 LL | #[derive(Debug)]
    | ^^^^^^^^^^^^^^^^
 
+error[E0658]: inner macro attributes are unstable
+  --> $DIR/issue-43106-gating-of-derive.rs:7:20
+   |
+LL |     mod inner { #![derive(Debug)] }
+   |                    ^^^^^^
+   |
+   = note: see issue #54726 <https://github.com/rust-lang/rust/issues/54726> for more information
+   = help: add `#![feature(custom_inner_attributes)]` to the crate attributes to enable
+
 error[E0774]: `derive` may only be applied to structs, enums and unions
   --> $DIR/issue-43106-gating-of-derive.rs:7:17
    |
 LL |     mod inner { #![derive(Debug)] }
-   |                 ^^^^^^^^^^^^^^^^^ help: try an outer attribute: `#[derive(Debug)]`
+   |                 ^^^^^^^^^^^^^^^^^
 
 error[E0774]: `derive` may only be applied to structs, enums and unions
-  --> $DIR/issue-43106-gating-of-derive.rs:10:5
+  --> $DIR/issue-43106-gating-of-derive.rs:11:5
    |
 LL |     #[derive(Debug)]
    |     ^^^^^^^^^^^^^^^^
 
 error[E0774]: `derive` may only be applied to structs, enums and unions
-  --> $DIR/issue-43106-gating-of-derive.rs:23:5
+  --> $DIR/issue-43106-gating-of-derive.rs:24:5
    |
 LL |     #[derive(Debug)]
    |     ^^^^^^^^^^^^^^^^
 
 error[E0774]: `derive` may only be applied to structs, enums and unions
-  --> $DIR/issue-43106-gating-of-derive.rs:27:5
+  --> $DIR/issue-43106-gating-of-derive.rs:28:5
    |
 LL |     #[derive(Debug)]
    |     ^^^^^^^^^^^^^^^^
 
-error: aborting due to 5 previous errors
+error: aborting due to 6 previous errors
 
-For more information about this error, try `rustc --explain E0774`.
+Some errors have detailed explanations: E0658, E0774.
+For more information about an error, try `rustc --explain E0658`.

src/test/ui/issues/issue-49934-errors.rs

@@ -1,11 +1,8 @@
-fn foo<#[derive(Debug)] T>() {
-//~^ ERROR `derive` may only be applied to structs, enums and unions
+fn foo<#[derive(Debug)] T>() { //~ ERROR expected non-macro attribute, found attribute macro
     match 0 {
-        #[derive(Debug)]
-        //~^ ERROR `derive` may only be applied to structs, enums and unions
+        #[derive(Debug)] //~ ERROR expected non-macro attribute, found attribute macro
         _ => (),
     }
 }
 
-fn main() {
-}
+fn main() {}

src/test/ui/issues/issue-49934-errors.stderr

@@ -1,15 +1,14 @@
-error[E0774]: `derive` may only be applied to structs, enums and unions
-  --> $DIR/issue-49934-errors.rs:1:8
+error: expected non-macro attribute, found attribute macro `derive`
+  --> $DIR/issue-49934-errors.rs:1:10
    |
 LL | fn foo<#[derive(Debug)] T>() {
-   |        ^^^^^^^^^^^^^^^^
+   |          ^^^^^^ not a non-macro attribute
 
-error[E0774]: `derive` may only be applied to structs, enums and unions
-  --> $DIR/issue-49934-errors.rs:4:9
+error: expected non-macro attribute, found attribute macro `derive`
+  --> $DIR/issue-49934-errors.rs:3:11
    |
 LL |         #[derive(Debug)]
-   |         ^^^^^^^^^^^^^^^^
+   |           ^^^^^^ not a non-macro attribute
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0774`.

src/test/ui/issues/issue-49934.rs

@@ -1,7 +1,4 @@
-// check-pass
-
 #![feature(stmt_expr_attributes)]
-#![warn(unused_attributes)] //~ NOTE the lint level is defined here
 
 fn main() {
     // fold_stmt (Item)
@@ -10,26 +7,24 @@ fn main() {
     struct Foo;
 
     // fold_stmt (Mac)
-    #[derive(Debug)]
-    //~^ WARN `#[derive]` does nothing on macro invocations
-    //~| NOTE this may become a hard error in a future release
+    #[derive(Debug)] //~ ERROR `derive` may only be applied to structs, enums and unions
     println!("Hello, world!");
 
     // fold_stmt (Semi)
-    #[derive(Debug)] //~ WARN unused attribute
+    #[derive(Debug)] //~ ERROR `derive` may only be applied to structs, enums and unions
     "Hello, world!";
 
     // fold_stmt (Local)
-    #[derive(Debug)] //~ WARN unused attribute
+    #[derive(Debug)] //~ ERROR `derive` may only be applied to structs, enums and unions
     let _ = "Hello, world!";
 
     // visit_expr
     let _ = #[derive(Debug)] "Hello, world!";
-    //~^ WARN unused attribute
+    //~^ ERROR `derive` may only be applied to structs, enums and unions
 
     let _ = [
         // filter_map_expr
-        #[derive(Debug)] //~ WARN unused attribute
-        "Hello, world!"
+        #[derive(Debug)] //~ ERROR `derive` may only be applied to structs, enums and unions
+        "Hello, world!",
     ];
 }

src/test/ui/issues/issue-49934.stderr

@@ -1,40 +1,33 @@
-warning: `#[derive]` does nothing on macro invocations
-  --> $DIR/issue-49934.rs:13:5
-   |
-LL |     #[derive(Debug)]
-   |     ^^^^^^^^^^^^^^^^
-   |
-   = note: this may become a hard error in a future release
-
-warning: unused attribute
-  --> $DIR/issue-49934.rs:19:5
-   |
-LL |     #[derive(Debug)]
-   |     ^^^^^^^^^^^^^^^^
-   |
-note: the lint level is defined here
-  --> $DIR/issue-49934.rs:4:9
-   |
-LL | #![warn(unused_attributes)]
-   |         ^^^^^^^^^^^^^^^^^
-
-warning: unused attribute
-  --> $DIR/issue-49934.rs:23:5
+error[E0774]: `derive` may only be applied to structs, enums and unions
+  --> $DIR/issue-49934.rs:10:5
    |
 LL |     #[derive(Debug)]
    |     ^^^^^^^^^^^^^^^^
 
-warning: unused attribute
-  --> $DIR/issue-49934.rs:27:13
+error[E0774]: `derive` may only be applied to structs, enums and unions
+  --> $DIR/issue-49934.rs:14:5
+   |
+LL |     #[derive(Debug)]
+   |     ^^^^^^^^^^^^^^^^
+
+error[E0774]: `derive` may only be applied to structs, enums and unions
+  --> $DIR/issue-49934.rs:18:5
+   |
+LL |     #[derive(Debug)]
+   |     ^^^^^^^^^^^^^^^^
+
+error[E0774]: `derive` may only be applied to structs, enums and unions
+  --> $DIR/issue-49934.rs:22:13
    |
 LL |     let _ = #[derive(Debug)] "Hello, world!";
    |             ^^^^^^^^^^^^^^^^
 
-warning: unused attribute
-  --> $DIR/issue-49934.rs:32:9
+error[E0774]: `derive` may only be applied to structs, enums and unions
+  --> $DIR/issue-49934.rs:27:9
    |
 LL |         #[derive(Debug)]
    |         ^^^^^^^^^^^^^^^^
 
-warning: 5 warnings emitted
+error: aborting due to 5 previous errors
 
+For more information about this error, try `rustc --explain E0774`.

src/test/ui/macros/builtin-std-paths-fail.stderr

@@ -1,3 +1,15 @@
+error[E0433]: failed to resolve: could not find `RustcDecodable` in `core`
+  --> $DIR/builtin-std-paths-fail.rs:2:11
+   |
+LL |     core::RustcDecodable,
+   |           ^^^^^^^^^^^^^^ could not find `RustcDecodable` in `core`
+
+error[E0433]: failed to resolve: could not find `RustcDecodable` in `core`
+  --> $DIR/builtin-std-paths-fail.rs:4:11
+   |
+LL |     core::RustcDecodable,
+   |           ^^^^^^^^^^^^^^ could not find `RustcDecodable` in `core`
+
 error[E0433]: failed to resolve: could not find `bench` in `core`
   --> $DIR/builtin-std-paths-fail.rs:7:9
    |
@@ -22,18 +34,6 @@ error[E0433]: failed to resolve: could not find `test` in `core`
 LL | #[core::test]
    |         ^^^^ could not find `test` in `core`
 
-error[E0433]: failed to resolve: could not find `RustcDecodable` in `core`
-  --> $DIR/builtin-std-paths-fail.rs:2:11
-   |
-LL |     core::RustcDecodable,
-   |           ^^^^^^^^^^^^^^ could not find `RustcDecodable` in `core`
-
-error[E0433]: failed to resolve: could not find `RustcDecodable` in `core`
-  --> $DIR/builtin-std-paths-fail.rs:4:11
-   |
-LL |     core::RustcDecodable,
-   |           ^^^^^^^^^^^^^^ could not find `RustcDecodable` in `core`
-
 error[E0433]: failed to resolve: could not find `RustcDecodable` in `core`
   --> $DIR/builtin-std-paths-fail.rs:4:11
    |
@@ -46,6 +46,18 @@ error[E0433]: failed to resolve: could not find `RustcDecodable` in `core`
 LL |     core::RustcDecodable,
    |           ^^^^^^^^^^^^^^ could not find `RustcDecodable` in `core`
 
+error[E0433]: failed to resolve: could not find `RustcDecodable` in `std`
+  --> $DIR/builtin-std-paths-fail.rs:14:10
+   |
+LL |     std::RustcDecodable,
+   |          ^^^^^^^^^^^^^^ could not find `RustcDecodable` in `std`
+
+error[E0433]: failed to resolve: could not find `RustcDecodable` in `std`
+  --> $DIR/builtin-std-paths-fail.rs:16:10
+   |
+LL |     std::RustcDecodable,
+   |          ^^^^^^^^^^^^^^ could not find `RustcDecodable` in `std`
+
 error[E0433]: failed to resolve: could not find `bench` in `std`
   --> $DIR/builtin-std-paths-fail.rs:19:8
    |
@@ -70,18 +82,6 @@ error[E0433]: failed to resolve: could not find `test` in `std`
 LL | #[std::test]
    |        ^^^^ could not find `test` in `std`
 
-error[E0433]: failed to resolve: could not find `RustcDecodable` in `std`
-  --> $DIR/builtin-std-paths-fail.rs:14:10
-   |
-LL |     std::RustcDecodable,
-   |          ^^^^^^^^^^^^^^ could not find `RustcDecodable` in `std`
-
-error[E0433]: failed to resolve: could not find `RustcDecodable` in `std`
-  --> $DIR/builtin-std-paths-fail.rs:16:10
-   |
-LL |     std::RustcDecodable,
-   |          ^^^^^^^^^^^^^^ could not find `RustcDecodable` in `std`
-
 error[E0433]: failed to resolve: could not find `RustcDecodable` in `std`
   --> $DIR/builtin-std-paths-fail.rs:16:10
    |

src/test/ui/malformed/issue-69341-malformed-derive-inert.rs

@@ -1,9 +1,6 @@
 fn main() {}
 
 struct CLI {
-    #[derive(parse())]
-    //~^ ERROR traits in `#[derive(...)]` don't accept arguments
-    //~| ERROR cannot find derive macro `parse` in this scope
+    #[derive(parse())] //~ ERROR expected non-macro attribute, found attribute macro
     path: (),
-    //~^ ERROR `derive` may only be applied to structs, enums and unions
 }

src/test/ui/malformed/issue-69341-malformed-derive-inert.stderr

@@ -1,21 +1,8 @@
-error: traits in `#[derive(...)]` don't accept arguments
-  --> $DIR/issue-69341-malformed-derive-inert.rs:4:19
+error: expected non-macro attribute, found attribute macro `derive`
+  --> $DIR/issue-69341-malformed-derive-inert.rs:4:7
    |
 LL |     #[derive(parse())]
-   |                   ^^ help: remove the arguments
+   |       ^^^^^^ not a non-macro attribute
 
-error[E0774]: `derive` may only be applied to structs, enums and unions
-  --> $DIR/issue-69341-malformed-derive-inert.rs:7:5
-   |
-LL |     path: (),
-   |     ^^^^^^^^
+error: aborting due to previous error
 
-error: cannot find derive macro `parse` in this scope
-  --> $DIR/issue-69341-malformed-derive-inert.rs:4:14
-   |
-LL |     #[derive(parse())]
-   |              ^^^^^
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0774`.

src/test/ui/malformed/malformed-derive-entry.stderr

@@ -14,7 +14,7 @@ error: malformed `derive` attribute input
   --> $DIR/malformed-derive-entry.rs:11:1
    |
 LL | #[derive]
-   | ^^^^^^^^^ help: missing traits to be derived: `#[derive(Trait1, Trait2, ...)]`
+   | ^^^^^^^^^ help: must be of the form: `#[derive(Trait1, Trait2, ...)]`
 
 error[E0277]: the trait bound `Test1: Clone` is not satisfied
   --> $DIR/malformed-derive-entry.rs:1:10

src/test/ui/malformed/malformed-special-attrs.stderr

@@ -18,13 +18,13 @@ error: malformed `derive` attribute input
   --> $DIR/malformed-special-attrs.rs:7:1
    |
 LL | #[derive]
-   | ^^^^^^^^^ help: missing traits to be derived: `#[derive(Trait1, Trait2, ...)]`
+   | ^^^^^^^^^ help: must be of the form: `#[derive(Trait1, Trait2, ...)]`
 
 error: malformed `derive` attribute input
   --> $DIR/malformed-special-attrs.rs:10:1
    |
 LL | #[derive = ""]
-   | ^^^^^^^^^^^^^^ help: missing traits to be derived: `#[derive(Trait1, Trait2, ...)]`
+   | ^^^^^^^^^^^^^^ help: must be of the form: `#[derive(Trait1, Trait2, ...)]`
 
 error: aborting due to 4 previous errors
 

src/test/ui/proc-macro/attribute-after-derive.rs

@@ -0,0 +1,28 @@
+// Macro attributes are allowed after `#[derive]` and
+// `#[derive]` fully configures the item for following attributes.
+
+// check-pass
+// compile-flags: -Z span-debug
+// aux-build: test-macros.rs
+
+#![no_std] // Don't load unnecessary hygiene information from std
+extern crate std;
+
+#[macro_use]
+extern crate test_macros;
+
+#[print_attr]
+#[derive(Print)]
+struct AttributeDerive {
+    #[cfg(FALSE)]
+    field: u8,
+}
+
+#[derive(Print)]
+#[print_attr]
+struct DeriveAttribute {
+    #[cfg(FALSE)]
+    field: u8,
+}
+
+fn main() {}

src/test/ui/proc-macro/attribute-after-derive.stdout

@@ -0,0 +1,148 @@
+PRINT-ATTR INPUT (DISPLAY): #[derive(Print)] struct AttributeDerive { #[cfg(FALSE)] field : u8, }
+PRINT-ATTR INPUT (DEBUG): TokenStream [
+    Punct {
+        ch: '#',
+        spacing: Alone,
+        span: $DIR/attribute-after-derive.rs:15:1: 15:2 (#0),
+    },
+    Group {
+        delimiter: Bracket,
+        stream: TokenStream [
+            Ident {
+                ident: "derive",
+                span: $DIR/attribute-after-derive.rs:15:3: 15:9 (#0),
+            },
+            Group {
+                delimiter: Parenthesis,
+                stream: TokenStream [
+                    Ident {
+                        ident: "Print",
+                        span: $DIR/attribute-after-derive.rs:15:10: 15:15 (#0),
+                    },
+                ],
+                span: $DIR/attribute-after-derive.rs:15:9: 15:16 (#0),
+            },
+        ],
+        span: $DIR/attribute-after-derive.rs:15:2: 15:17 (#0),
+    },
+    Ident {
+        ident: "struct",
+        span: $DIR/attribute-after-derive.rs:16:1: 16:7 (#0),
+    },
+    Ident {
+        ident: "AttributeDerive",
+        span: $DIR/attribute-after-derive.rs:16:8: 16:23 (#0),
+    },
+    Group {
+        delimiter: Brace,
+        stream: TokenStream [
+            Punct {
+                ch: '#',
+                spacing: Alone,
+                span: $DIR/attribute-after-derive.rs:17:5: 17:6 (#0),
+            },
+            Group {
+                delimiter: Bracket,
+                stream: TokenStream [
+                    Ident {
+                        ident: "cfg",
+                        span: $DIR/attribute-after-derive.rs:17:7: 17:10 (#0),
+                    },
+                    Group {
+                        delimiter: Parenthesis,
+                        stream: TokenStream [
+                            Ident {
+                                ident: "FALSE",
+                                span: $DIR/attribute-after-derive.rs:17:11: 17:16 (#0),
+                            },
+                        ],
+                        span: $DIR/attribute-after-derive.rs:17:10: 17:17 (#0),
+                    },
+                ],
+                span: $DIR/attribute-after-derive.rs:17:6: 17:18 (#0),
+            },
+            Ident {
+                ident: "field",
+                span: $DIR/attribute-after-derive.rs:18:5: 18:10 (#0),
+            },
+            Punct {
+                ch: ':',
+                spacing: Alone,
+                span: $DIR/attribute-after-derive.rs:18:10: 18:11 (#0),
+            },
+            Ident {
+                ident: "u8",
+                span: $DIR/attribute-after-derive.rs:18:12: 18:14 (#0),
+            },
+            Punct {
+                ch: ',',
+                spacing: Alone,
+                span: $DIR/attribute-after-derive.rs:18:14: 18:15 (#0),
+            },
+        ],
+        span: $DIR/attribute-after-derive.rs:16:24: 19:2 (#0),
+    },
+]
+PRINT-DERIVE INPUT (DISPLAY): struct AttributeDerive { }
+PRINT-DERIVE INPUT (DEBUG): TokenStream [
+    Ident {
+        ident: "struct",
+        span: $DIR/attribute-after-derive.rs:16:1: 19:2 (#0),
+    },
+    Ident {
+        ident: "AttributeDerive",
+        span: $DIR/attribute-after-derive.rs:16:1: 19:2 (#0),
+    },
+    Group {
+        delimiter: Brace,
+        stream: TokenStream [],
+        span: $DIR/attribute-after-derive.rs:16:1: 19:2 (#0),
+    },
+]
+PRINT-ATTR INPUT (DISPLAY): struct DeriveAttribute { }
+PRINT-ATTR INPUT (DEBUG): TokenStream [
+    Ident {
+        ident: "struct",
+        span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
+    },
+    Ident {
+        ident: "DeriveAttribute",
+        span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
+    },
+    Group {
+        delimiter: Brace,
+        stream: TokenStream [],
+        span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
+    },
+]
+PRINT-DERIVE INPUT (DISPLAY): #[print_attr] struct DeriveAttribute { }
+PRINT-DERIVE INPUT (DEBUG): TokenStream [
+    Punct {
+        ch: '#',
+        spacing: Alone,
+        span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
+    },
+    Group {
+        delimiter: Bracket,
+        stream: TokenStream [
+            Ident {
+                ident: "print_attr",
+                span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
+            },
+        ],
+        span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
+    },
+    Ident {
+        ident: "struct",
+        span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
+    },
+    Ident {
+        ident: "DeriveAttribute",
+        span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
+    },
+    Group {
+        delimiter: Brace,
+        stream: TokenStream [],
+        span: $DIR/attribute-after-derive.rs:23:1: 26:2 (#0),
+    },
+]

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

@@ -1,14 +0,0 @@
-// aux-build:test-macros.rs
-
-#[macro_use]
-extern crate test_macros;
-
-#[identity_attr] // OK
-#[derive(Clone)]
-struct Before;
-
-#[derive(Clone)]
-#[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 +0,0 @@
-error: macro attributes must be placed before `#[derive]`
-  --> $DIR/attribute-order-restricted.rs:11:1
-   |
-LL | #[identity_attr]
-   | ^^^^^^^^^^^^^^^^
-
-error: aborting due to previous error
-

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

@@ -17,6 +17,8 @@ macro_rules! gen_helper_use {
 }
 
 #[empty_helper] //~ ERROR `empty_helper` is ambiguous
+                //~| WARN derive helper attribute is used before it is introduced
+                //~| WARN this was previously accepted
 #[derive(Empty)]
 struct S {
     #[empty_helper] // OK, no ambiguity, derive helpers have highest priority

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

@@ -1,17 +1,17 @@
 error: cannot use a derive helper attribute through an import
-  --> $DIR/derive-helper-shadowing.rs:40:15
+  --> $DIR/derive-helper-shadowing.rs:42:15
    |
 LL |             #[renamed]
    |               ^^^^^^^
    |
 note: the derive helper attribute imported here
-  --> $DIR/derive-helper-shadowing.rs:39:17
+  --> $DIR/derive-helper-shadowing.rs:41:17
    |
 LL |             use empty_helper as renamed;
    |                 ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: cannot find attribute `empty_helper` in this scope
-  --> $DIR/derive-helper-shadowing.rs:36:22
+  --> $DIR/derive-helper-shadowing.rs:38:22
    |
 LL |             #[derive(GenHelperUse)]
    |                      ^^^^^^^^^^^^
@@ -30,13 +30,13 @@ LL |             gen_helper_use!();
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0659]: `empty_helper` is ambiguous (name vs any other name during import resolution)
-  --> $DIR/derive-helper-shadowing.rs:24:13
+  --> $DIR/derive-helper-shadowing.rs:26:13
    |
 LL |         use empty_helper;
    |             ^^^^^^^^^^^^ ambiguous name
    |
 note: `empty_helper` could refer to the derive helper attribute defined here
-  --> $DIR/derive-helper-shadowing.rs:20:10
+  --> $DIR/derive-helper-shadowing.rs:22:10
    |
 LL | #[derive(Empty)]
    |          ^^^^^
@@ -54,7 +54,7 @@ LL | #[empty_helper]
    |   ^^^^^^^^^^^^ ambiguous name
    |
 note: `empty_helper` could refer to the derive helper attribute defined here
-  --> $DIR/derive-helper-shadowing.rs:20:10
+  --> $DIR/derive-helper-shadowing.rs:22:10
    |
 LL | #[derive(Empty)]
    |          ^^^^^
@@ -65,6 +65,19 @@ 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 5 previous errors
+warning: derive helper attribute is used before it is introduced
+  --> $DIR/derive-helper-shadowing.rs:19:3
+   |
+LL | #[empty_helper]
+   |   ^^^^^^^^^^^^
+...
+LL | #[derive(Empty)]
+   |          ----- the attribute is introduced here
+   |
+   = note: `#[warn(legacy_derive_helpers)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79202 <https://github.com/rust-lang/rust/issues/79202>
+
+error: aborting due to 5 previous errors; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0659`.

src/test/ui/proc-macro/derive-helper-vs-legacy.rs

@@ -0,0 +1,12 @@
+// check-pass
+// aux-build:test-macros.rs
+
+#[macro_use]
+extern crate test_macros;
+
+#[derive(Empty)]
+#[empty_helper] // OK, this is both derive helper and legacy derive helper
+#[derive(Empty)]
+struct S;
+
+fn main() {}

src/test/ui/proc-macro/derive-multiple-with-packed.rs

@@ -0,0 +1,11 @@
+// check-pass
+
+#[derive(Clone, Copy)]
+#[derive(Debug)] // OK, even if `Copy` is in the different `#[derive]`
+#[derive(PartialEq)] // OK too
+#[repr(packed)]
+struct CacheRecordHeader {
+    field: u64,
+}
+
+fn main() {}

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

@@ -4,8 +4,10 @@
 extern crate test_macros;
 use test_macros::empty_attr as empty_helper;
 
-#[derive(Empty)]
 #[empty_helper] //~ ERROR `empty_helper` is ambiguous
+                //~| WARN derive helper attribute is used before it is introduced
+                //~| WARN this was previously accepted
+#[derive(Empty)]
 struct S;
 
 fn main() {}

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

@@ -1,11 +1,11 @@
 error[E0659]: `empty_helper` is ambiguous (derive helper attribute vs any other name)
-  --> $DIR/helper-attr-blocked-by-import-ambig.rs:8:3
+  --> $DIR/helper-attr-blocked-by-import-ambig.rs:7:3
    |
 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
+  --> $DIR/helper-attr-blocked-by-import-ambig.rs:10:10
    |
 LL | #[derive(Empty)]
    |          ^^^^^
@@ -16,6 +16,19 @@ 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
+warning: derive helper attribute is used before it is introduced
+  --> $DIR/helper-attr-blocked-by-import-ambig.rs:7:3
+   |
+LL | #[empty_helper]
+   |   ^^^^^^^^^^^^
+...
+LL | #[derive(Empty)]
+   |          ----- the attribute is introduced here
+   |
+   = note: `#[warn(legacy_derive_helpers)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79202 <https://github.com/rust-lang/rust/issues/79202>
+
+error: aborting due to previous error; 1 warning emitted
 
 For more information about this error, try `rustc --explain E0659`.

src/test/ui/proc-macro/issue-75930-derive-cfg.rs

@@ -13,7 +13,8 @@
 #[macro_use]
 extern crate test_macros;
 
-#[print_helper(a)]
+#[print_helper(a)] //~ WARN derive helper attribute is used before it is introduced
+                   //~| WARN this was previously accepted
 #[cfg_attr(not(FALSE), allow(dead_code))]
 #[print_attr]
 #[derive(Print)]

src/test/ui/proc-macro/issue-75930-derive-cfg.stderr

@@ -0,0 +1,15 @@
+warning: derive helper attribute is used before it is introduced
+  --> $DIR/issue-75930-derive-cfg.rs:16:3
+   |
+LL | #[print_helper(a)]
+   |   ^^^^^^^^^^^^
+...
+LL | #[derive(Print)]
+   |          ----- the attribute is introduced here
+   |
+   = note: `#[warn(legacy_derive_helpers)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79202 <https://github.com/rust-lang/rust/issues/79202>
+
+warning: 1 warning emitted
+

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

@@ -4,10 +4,18 @@
 extern crate derive_b;
 
 #[B] //~ ERROR `B` is ambiguous
+     //~| WARN derive helper attribute is used before it is introduced
+     //~| WARN this was previously accepted
 #[C] //~ ERROR cannot find attribute `C` in this scope
 #[B(D)] //~ ERROR `B` is ambiguous
+        //~| WARN derive helper attribute is used before it is introduced
+        //~| WARN this was previously accepted
 #[B(E = "foo")] //~ ERROR `B` is ambiguous
+                //~| WARN derive helper attribute is used before it is introduced
+                //~| WARN this was previously accepted
 #[B(arbitrary tokens)] //~ ERROR `B` is ambiguous
+                       //~| WARN derive helper attribute is used before it is introduced
+                       //~| WARN this was previously accepted
 #[derive(B)]
 struct B;
 

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

@@ -1,5 +1,5 @@
 error: cannot find attribute `C` in this scope
-  --> $DIR/proc-macro-attributes.rs:7:3
+  --> $DIR/proc-macro-attributes.rs:9:3
    |
 LL | #[C]
    |   ^ help: a derive helper attribute with a similar name exists: `B`
@@ -11,41 +11,7 @@ LL | #[B]
    |   ^ ambiguous name
    |
 note: `B` could refer to the derive helper attribute defined here
-  --> $DIR/proc-macro-attributes.rs:11:10
-   |
-LL | #[derive(B)]
-   |          ^
-note: `B` could also refer to the derive macro imported here
-  --> $DIR/proc-macro-attributes.rs:3:1
-   |
-LL | #[macro_use]
-   | ^^^^^^^^^^^^
-
-error[E0659]: `B` is ambiguous (derive helper attribute vs any other name)
-  --> $DIR/proc-macro-attributes.rs:8:3
-   |
-LL | #[B(D)]
-   |   ^ ambiguous name
-   |
-note: `B` could refer to the derive helper attribute defined here
-  --> $DIR/proc-macro-attributes.rs:11:10
-   |
-LL | #[derive(B)]
-   |          ^
-note: `B` could also refer to the derive macro imported here
-  --> $DIR/proc-macro-attributes.rs:3:1
-   |
-LL | #[macro_use]
-   | ^^^^^^^^^^^^
-
-error[E0659]: `B` is ambiguous (derive helper attribute vs any other name)
-  --> $DIR/proc-macro-attributes.rs:9:3
-   |
-LL | #[B(E = "foo")]
-   |   ^ ambiguous name
-   |
-note: `B` could refer to the derive helper attribute defined here
-  --> $DIR/proc-macro-attributes.rs:11:10
+  --> $DIR/proc-macro-attributes.rs:19:10
    |
 LL | #[derive(B)]
    |          ^
@@ -58,11 +24,11 @@ LL | #[macro_use]
 error[E0659]: `B` is ambiguous (derive helper attribute vs any other name)
   --> $DIR/proc-macro-attributes.rs:10:3
    |
-LL | #[B(arbitrary tokens)]
+LL | #[B(D)]
    |   ^ ambiguous name
    |
 note: `B` could refer to the derive helper attribute defined here
-  --> $DIR/proc-macro-attributes.rs:11:10
+  --> $DIR/proc-macro-attributes.rs:19:10
    |
 LL | #[derive(B)]
    |          ^
@@ -72,6 +38,89 @@ note: `B` could also refer to the derive macro imported here
 LL | #[macro_use]
    | ^^^^^^^^^^^^
 
-error: aborting due to 5 previous errors
+error[E0659]: `B` is ambiguous (derive helper attribute vs any other name)
+  --> $DIR/proc-macro-attributes.rs:13:3
+   |
+LL | #[B(E = "foo")]
+   |   ^ ambiguous name
+   |
+note: `B` could refer to the derive helper attribute defined here
+  --> $DIR/proc-macro-attributes.rs:19:10
+   |
+LL | #[derive(B)]
+   |          ^
+note: `B` could also refer to the derive macro imported here
+  --> $DIR/proc-macro-attributes.rs:3:1
+   |
+LL | #[macro_use]
+   | ^^^^^^^^^^^^
+
+error[E0659]: `B` is ambiguous (derive helper attribute vs any other name)
+  --> $DIR/proc-macro-attributes.rs:16:3
+   |
+LL | #[B(arbitrary tokens)]
+   |   ^ ambiguous name
+   |
+note: `B` could refer to the derive helper attribute defined here
+  --> $DIR/proc-macro-attributes.rs:19:10
+   |
+LL | #[derive(B)]
+   |          ^
+note: `B` could also refer to the derive macro imported here
+  --> $DIR/proc-macro-attributes.rs:3:1
+   |
+LL | #[macro_use]
+   | ^^^^^^^^^^^^
+
+warning: derive helper attribute is used before it is introduced
+  --> $DIR/proc-macro-attributes.rs:6:3
+   |
+LL | #[B]
+   |   ^
+...
+LL | #[derive(B)]
+   |          - the attribute is introduced here
+   |
+   = note: `#[warn(legacy_derive_helpers)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79202 <https://github.com/rust-lang/rust/issues/79202>
+
+warning: derive helper attribute is used before it is introduced
+  --> $DIR/proc-macro-attributes.rs:10:3
+   |
+LL | #[B(D)]
+   |   ^
+...
+LL | #[derive(B)]
+   |          - the attribute is introduced here
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79202 <https://github.com/rust-lang/rust/issues/79202>
+
+warning: derive helper attribute is used before it is introduced
+  --> $DIR/proc-macro-attributes.rs:13:3
+   |
+LL | #[B(E = "foo")]
+   |   ^
+...
+LL | #[derive(B)]
+   |          - the attribute is introduced here
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79202 <https://github.com/rust-lang/rust/issues/79202>
+
+warning: derive helper attribute is used before it is introduced
+  --> $DIR/proc-macro-attributes.rs:16:3
+   |
+LL | #[B(arbitrary tokens)]
+   |   ^
+...
+LL | #[derive(B)]
+   |          - the attribute is introduced here
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79202 <https://github.com/rust-lang/rust/issues/79202>
+
+error: aborting due to 5 previous errors; 4 warnings emitted
 
 For more information about this error, try `rustc --explain E0659`.

src/test/ui/proc-macro/reserved-macro-names.rs

@@ -17,9 +17,3 @@ pub fn cfg_attr(_: TokenStream, input: TokenStream) -> TokenStream {
     //~^ ERROR name `cfg_attr` is reserved in attribute namespace
     input
 }
-
-#[proc_macro_attribute]
-pub fn derive(_: TokenStream, input: TokenStream) -> TokenStream {
-    //~^ ERROR name `derive` is reserved in attribute namespace
-    input
-}

src/test/ui/proc-macro/reserved-macro-names.stderr

@@ -10,11 +10,5 @@ error: name `cfg_attr` is reserved in attribute namespace
 LL | pub fn cfg_attr(_: TokenStream, input: TokenStream) -> TokenStream {
    |        ^^^^^^^^
 
-error: name `derive` is reserved in attribute namespace
-  --> $DIR/reserved-macro-names.rs:22:8
-   |
-LL | pub fn derive(_: TokenStream, input: TokenStream) -> TokenStream {
-   |        ^^^^^^
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 

src/test/ui/span/issue-43927-non-ADT-derive.rs

@@ -1,10 +1,5 @@
-#![allow(dead_code)]
-
 #![derive(Debug, PartialEq, Eq)] // should be an outer attribute!
-//~^ ERROR `derive` may only be applied to structs, enums and unions
-//~| ERROR cannot determine resolution for the derive macro `Debug`
-//~| ERROR cannot determine resolution for the derive macro `PartialEq`
-//~| ERROR cannot determine resolution for the derive macro `Eq`
+//~^ ERROR cannot determine resolution for the attribute macro `derive`
 struct DerivedOn;
 
 fn main() {}

src/test/ui/span/issue-43927-non-ADT-derive.stderr

@@ -1,33 +1,10 @@
-error[E0774]: `derive` may only be applied to structs, enums and unions
-  --> $DIR/issue-43927-non-ADT-derive.rs:3:1
+error: cannot determine resolution for the attribute macro `derive`
+  --> $DIR/issue-43927-non-ADT-derive.rs:1:4
    |
 LL | #![derive(Debug, PartialEq, Eq)] // should be an outer attribute!
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try an outer attribute: `#[derive(Debug, PartialEq, Eq)]`
-
-error: cannot determine resolution for the derive macro `Debug`
-  --> $DIR/issue-43927-non-ADT-derive.rs:3:11
-   |
-LL | #![derive(Debug, PartialEq, Eq)] // should be an outer attribute!
-   |           ^^^^^
+   |    ^^^^^^
    |
    = note: import resolution is stuck, try simplifying macro imports
 
-error: cannot determine resolution for the derive macro `PartialEq`
-  --> $DIR/issue-43927-non-ADT-derive.rs:3:18
-   |
-LL | #![derive(Debug, PartialEq, Eq)] // should be an outer attribute!
-   |                  ^^^^^^^^^
-   |
-   = note: import resolution is stuck, try simplifying macro imports
+error: aborting due to previous error
 
-error: cannot determine resolution for the derive macro `Eq`
-  --> $DIR/issue-43927-non-ADT-derive.rs:3:29
-   |
-LL | #![derive(Debug, PartialEq, Eq)] // should be an outer attribute!
-   |                             ^^
-   |
-   = note: import resolution is stuck, try simplifying macro imports
-
-error: aborting due to 4 previous errors
-
-For more information about this error, try `rustc --explain E0774`.

src/test/ui/span/macro-ty-params.rs

@@ -9,5 +9,5 @@ macro_rules! foo { () => () }
 fn main() {
     foo::<T>!(); //~ ERROR generic arguments in macro path
     foo::<>!(); //~ ERROR generic arguments in macro path
-    m!(Default<>); //~ ERROR generic arguments in macro path
+    m!(Default<>); //~ ERROR unexpected generic arguments in path
 }

src/test/ui/span/macro-ty-params.stderr

@@ -10,7 +10,7 @@ error: generic arguments in macro path
 LL |     foo::<>!();
    |          ^^
 
-error: generic arguments in macro path
+error: unexpected generic arguments in path
   --> $DIR/macro-ty-params.rs:12:15
    |
 LL |     m!(Default<>);