Detect pub structs never constructed and unused associated constants in traits

29 files changed, 162 insertions, 43 deletions

diff --git a/tests/ui/coherence/re-rebalance-coherence.rs b/tests/ui/coherence/re-rebalance-coherence.rs
index 9c176d5b1b1..5383a634617 100644
--- a/tests/ui/coherence/re-rebalance-coherence.rs
+++ b/tests/ui/coherence/re-rebalance-coherence.rs
@@ -4,6 +4,7 @@
 extern crate re_rebalance_coherence_lib as lib;
 use lib::*;
 
+#[allow(dead_code)]
 struct Oracle;
 impl Backend for Oracle {}
 impl<'a, T:'a, Tab> QueryFragment<Oracle> for BatchInsert<'a, T, Tab> {}
diff --git a/tests/ui/const-generics/defaults/repr-c-issue-82792.rs b/tests/ui/const-generics/defaults/repr-c-issue-82792.rs
index c23187598bc..4bf2fa761ea 100644
--- a/tests/ui/const-generics/defaults/repr-c-issue-82792.rs
+++ b/tests/ui/const-generics/defaults/repr-c-issue-82792.rs
@@ -2,6 +2,7 @@
 
 //@ run-pass
 
+#[allow(dead_code)]
 #[repr(C)]
 pub struct Loaf<T: Sized, const N: usize = 1> {
     head: [T; N],
diff --git a/tests/ui/const-generics/generic_const_exprs/associated-consts.rs b/tests/ui/const-generics/generic_const_exprs/associated-consts.rs
index 5d2198f50ad..50a6102c605 100644
--- a/tests/ui/const-generics/generic_const_exprs/associated-consts.rs
+++ b/tests/ui/const-generics/generic_const_exprs/associated-consts.rs
@@ -16,7 +16,8 @@ impl BlockCipher for BarCipher {
     const BLOCK_SIZE: usize = 32;
 }
 
-pub struct Block<C>(#[allow(dead_code)] C);
+#[allow(dead_code)]
+pub struct Block<C>(C);
 
 pub fn test<C: BlockCipher, const M: usize>()
 where
diff --git a/tests/ui/const-generics/transparent-maybeunit-array-wrapper.rs b/tests/ui/const-generics/transparent-maybeunit-array-wrapper.rs
index 419d605d0c8..35c41ae4615 100644
--- a/tests/ui/const-generics/transparent-maybeunit-array-wrapper.rs
+++ b/tests/ui/const-generics/transparent-maybeunit-array-wrapper.rs
@@ -6,6 +6,7 @@
 
 use std::mem::MaybeUninit;
 
+#[allow(dead_code)]
 #[repr(transparent)]
 pub struct MaybeUninitWrapper<const N: usize>(MaybeUninit<[u64; N]>);
 
diff --git a/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.rs b/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.rs
index 6ab1fb7b039..885dacc727a 100644
--- a/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.rs
+++ b/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.rs
@@ -1,9 +1,9 @@
 #![forbid(dead_code)]
 
 #[derive(Debug)]
-pub struct Whatever {
+pub struct Whatever { //~ ERROR struct `Whatever` is never constructed
     pub field0: (),
-    field1: (), //~ ERROR fields `field1`, `field2`, `field3`, and `field4` are never read
+    field1: (),
     field2: (),
     field3: (),
     field4: (),
diff --git a/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.stderr b/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.stderr
index e9b757b6bae..e10d28ad03a 100644
--- a/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.stderr
+++ b/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.stderr
@@ -1,19 +1,9 @@
-error: fields `field1`, `field2`, `field3`, and `field4` are never read
-  --> $DIR/clone-debug-dead-code-in-the-same-struct.rs:6:5
+error: struct `Whatever` is never constructed
+  --> $DIR/clone-debug-dead-code-in-the-same-struct.rs:4:12
    |
 LL | pub struct Whatever {
-   |            -------- fields in this struct
-LL |     pub field0: (),
-LL |     field1: (),
-   |     ^^^^^^
-LL |     field2: (),
-   |     ^^^^^^
-LL |     field3: (),
-   |     ^^^^^^
-LL |     field4: (),
-   |     ^^^^^^
+   |            ^^^^^^^^
    |
-   = note: `Whatever` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
 note: the lint level is defined here
   --> $DIR/clone-debug-dead-code-in-the-same-struct.rs:1:11
    |
diff --git a/tests/ui/issues/issue-5708.rs b/tests/ui/issues/issue-5708.rs
index ce9ef78ffcd..89ea9fbdcd8 100644
--- a/tests/ui/issues/issue-5708.rs
+++ b/tests/ui/issues/issue-5708.rs
@@ -44,6 +44,7 @@ pub trait MyTrait<T> {
     fn dummy(&self, t: T) -> T { panic!() }
 }
 
+#[allow(dead_code)]
 pub struct MyContainer<'a, T:'a> {
     foos: Vec<&'a (dyn MyTrait<T>+'a)> ,
 }
diff --git a/tests/ui/lint/dead-code/lint-dead-code-1.rs b/tests/ui/lint/dead-code/lint-dead-code-1.rs
index ddcafedf7bc..3386dfa4747 100644
--- a/tests/ui/lint/dead-code/lint-dead-code-1.rs
+++ b/tests/ui/lint/dead-code/lint-dead-code-1.rs
@@ -46,11 +46,10 @@ struct SemiUsedStruct;
 impl SemiUsedStruct {
     fn la_la_la() {}
 }
-struct StructUsedAsField;
+struct StructUsedAsField; //~ ERROR struct `StructUsedAsField` is never constructed
 pub struct StructUsedInEnum;
 struct StructUsedInGeneric;
-pub struct PubStruct2 {
-    #[allow(dead_code)]
+pub struct PubStruct2 { //~ ERROR struct `PubStruct2` is never constructed
     struct_used_as_field: *const StructUsedAsField
 }
 
diff --git a/tests/ui/lint/dead-code/lint-dead-code-1.stderr b/tests/ui/lint/dead-code/lint-dead-code-1.stderr
index eb728b5b930..b0163df8855 100644
--- a/tests/ui/lint/dead-code/lint-dead-code-1.stderr
+++ b/tests/ui/lint/dead-code/lint-dead-code-1.stderr
@@ -22,14 +22,26 @@ error: struct `PrivStruct` is never constructed
 LL | struct PrivStruct;
    |        ^^^^^^^^^^
 
+error: struct `StructUsedAsField` is never constructed
+  --> $DIR/lint-dead-code-1.rs:49:8
+   |
+LL | struct StructUsedAsField;
+   |        ^^^^^^^^^^^^^^^^^
+
+error: struct `PubStruct2` is never constructed
+  --> $DIR/lint-dead-code-1.rs:52:12
+   |
+LL | pub struct PubStruct2 {
+   |            ^^^^^^^^^^
+
 error: enum `priv_enum` is never used
-  --> $DIR/lint-dead-code-1.rs:64:6
+  --> $DIR/lint-dead-code-1.rs:63:6
    |
 LL | enum priv_enum { foo2, bar2 }
    |      ^^^^^^^^^
 
 error: variant `bar3` is never constructed
-  --> $DIR/lint-dead-code-1.rs:67:5
+  --> $DIR/lint-dead-code-1.rs:66:5
    |
 LL | enum used_enum {
    |      --------- variant in this enum
@@ -38,25 +50,25 @@ LL |     bar3
    |     ^^^^
 
 error: function `priv_fn` is never used
-  --> $DIR/lint-dead-code-1.rs:88:4
+  --> $DIR/lint-dead-code-1.rs:87:4
    |
 LL | fn priv_fn() {
    |    ^^^^^^^
 
 error: function `foo` is never used
-  --> $DIR/lint-dead-code-1.rs:93:4
+  --> $DIR/lint-dead-code-1.rs:92:4
    |
 LL | fn foo() {
    |    ^^^
 
 error: function `bar` is never used
-  --> $DIR/lint-dead-code-1.rs:98:4
+  --> $DIR/lint-dead-code-1.rs:97:4
    |
 LL | fn bar() {
    |    ^^^
 
 error: function `baz` is never used
-  --> $DIR/lint-dead-code-1.rs:102:4
+  --> $DIR/lint-dead-code-1.rs:101:4
    |
 LL | fn baz() -> impl Copy {
    |    ^^^
@@ -67,5 +79,5 @@ error: struct `Bar` is never constructed
 LL |     pub struct Bar;
    |                ^^^
 
-error: aborting due to 10 previous errors
+error: aborting due to 12 previous errors
 
diff --git a/tests/ui/lint/dead-code/unused-assoc-const.rs b/tests/ui/lint/dead-code/unused-assoc-const.rs
new file mode 100644
index 00000000000..36e8315ad36
--- /dev/null
+++ b/tests/ui/lint/dead-code/unused-assoc-const.rs
@@ -0,0 +1,20 @@
+#![deny(dead_code)]
+
+trait Trait {
+    const UNUSED_CONST: i32; //~ ERROR associated constant `UNUSED_CONST` is never used
+    const USED_CONST: i32;
+
+    fn foo(&self) {}
+}
+
+pub struct T(());
+
+impl Trait for T {
+    const UNUSED_CONST: i32 = 0;
+    const USED_CONST: i32 = 1;
+}
+
+fn main() {
+    T(()).foo();
+    T::USED_CONST;
+}
diff --git a/tests/ui/lint/dead-code/unused-assoc-const.stderr b/tests/ui/lint/dead-code/unused-assoc-const.stderr
new file mode 100644
index 00000000000..78296d70663
--- /dev/null
+++ b/tests/ui/lint/dead-code/unused-assoc-const.stderr
@@ -0,0 +1,16 @@
+error: associated constant `UNUSED_CONST` is never used
+  --> $DIR/unused-assoc-const.rs:4:11
+   |
+LL | trait Trait {
+   |       ----- associated constant in this trait
+LL |     const UNUSED_CONST: i32;
+   |           ^^^^^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/unused-assoc-const.rs:1:9
+   |
+LL | #![deny(dead_code)]
+   |         ^^^^^^^^^
+
+error: aborting due to 1 previous error
+
diff --git a/tests/ui/lint/dead-code/unused-pub-struct.rs b/tests/ui/lint/dead-code/unused-pub-struct.rs
new file mode 100644
index 00000000000..aaf4dd612de
--- /dev/null
+++ b/tests/ui/lint/dead-code/unused-pub-struct.rs
@@ -0,0 +1,48 @@
+#![deny(dead_code)]
+
+pub struct NotLint1(());
+pub struct NotLint2(std::marker::PhantomData<i32>);
+
+pub struct NeverConstructed(i32); //~ ERROR struct `NeverConstructed` is never constructed
+
+impl NeverConstructed {
+    pub fn not_construct_self(&self) {}
+}
+
+impl Clone for NeverConstructed {
+    fn clone(&self) -> NeverConstructed {
+        NeverConstructed(0)
+    }
+}
+
+pub trait Trait {
+    fn not_construct_self(&self);
+}
+
+impl Trait for NeverConstructed {
+    fn not_construct_self(&self) {
+        self.0;
+    }
+}
+
+pub struct Constructed(i32);
+
+impl Constructed {
+    pub fn construct_self() -> Self {
+        Constructed(0)
+    }
+}
+
+impl Clone for Constructed {
+    fn clone(&self) -> Constructed {
+        Constructed(0)
+    }
+}
+
+impl Trait for Constructed {
+    fn not_construct_self(&self) {
+        self.0;
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/lint/dead-code/unused-pub-struct.stderr b/tests/ui/lint/dead-code/unused-pub-struct.stderr
new file mode 100644
index 00000000000..3667ddb97bd
--- /dev/null
+++ b/tests/ui/lint/dead-code/unused-pub-struct.stderr
@@ -0,0 +1,14 @@
+error: struct `NeverConstructed` is never constructed
+  --> $DIR/unused-pub-struct.rs:6:12
+   |
+LL | pub struct NeverConstructed(i32);
+   |            ^^^^^^^^^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/unused-pub-struct.rs:1:9
+   |
+LL | #![deny(dead_code)]
+   |         ^^^^^^^^^
+
+error: aborting due to 1 previous error
+
diff --git a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.fixed b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.fixed
index a851300a982..e9c89807fa5 100644
--- a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.fixed
+++ b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.fixed
@@ -1,7 +1,8 @@
 // Regression test for issues #100790 and #106439.
 //@ run-rustfix
 
-pub struct Example(#[allow(dead_code)] usize)
+#[allow(dead_code)]
+pub struct Example(usize)
 where
     (): Sized;
 //~^^^ ERROR where clauses are not allowed before tuple struct bodies
diff --git a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.rs b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.rs
index 10f435859f1..3bd0f51ec2c 100644
--- a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.rs
+++ b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.rs
@@ -1,10 +1,11 @@
 // Regression test for issues #100790 and #106439.
 //@ run-rustfix
 
+#[allow(dead_code)]
 pub struct Example
 where
     (): Sized,
-(#[allow(dead_code)] usize);
+(usize);
 //~^^^ ERROR where clauses are not allowed before tuple struct bodies
 
 struct _Demo
diff --git a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.stderr b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.stderr
index ddbf237e866..77eafa6bea3 100644
--- a/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.stderr
+++ b/tests/ui/parser/recover/recover-where-clause-before-tuple-struct-body-0.stderr
@@ -1,23 +1,23 @@
 error: where clauses are not allowed before tuple struct bodies
-  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:5:1
+  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:6:1
    |
 LL |   pub struct Example
    |              ------- while parsing this tuple struct
 LL | / where
 LL | |     (): Sized,
    | |______________^ unexpected where clause
-LL |   (#[allow(dead_code)] usize);
-   |   --------------------------- the struct body
+LL |   (usize);
+   |   ------- the struct body
    |
 help: move the body before the where clause
    |
-LL ~ pub struct Example(#[allow(dead_code)] usize)
+LL ~ pub struct Example(usize)
 LL | where
 LL ~     (): Sized;
    |
 
 error: where clauses are not allowed before tuple struct bodies
-  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:11:1
+  --> $DIR/recover-where-clause-before-tuple-struct-body-0.rs:12:1
    |
 LL |   struct _Demo
    |          ----- while parsing this tuple struct
diff --git a/tests/ui/pub/pub-ident-struct-4.fixed b/tests/ui/pub/pub-ident-struct-4.fixed
index 5fedbb72437..a62ece43ece 100644
--- a/tests/ui/pub/pub-ident-struct-4.fixed
+++ b/tests/ui/pub/pub-ident-struct-4.fixed
@@ -1,6 +1,7 @@
 //@ run-rustfix
 
-pub struct T(#[allow(dead_code)] String);
+#[allow(dead_code)]
+pub struct T(String);
 //~^ ERROR missing `struct` for struct definition
 
 fn main() {}
diff --git a/tests/ui/pub/pub-ident-struct-4.rs b/tests/ui/pub/pub-ident-struct-4.rs
index 5c721c25a78..0d56a31beaf 100644
--- a/tests/ui/pub/pub-ident-struct-4.rs
+++ b/tests/ui/pub/pub-ident-struct-4.rs
@@ -1,6 +1,7 @@
 //@ run-rustfix
 
-pub T(#[allow(dead_code)] String);
+#[allow(dead_code)]
+pub T(String);
 //~^ ERROR missing `struct` for struct definition
 
 fn main() {}
diff --git a/tests/ui/pub/pub-ident-struct-4.stderr b/tests/ui/pub/pub-ident-struct-4.stderr
index 5fbb02c8673..ec136783211 100644
--- a/tests/ui/pub/pub-ident-struct-4.stderr
+++ b/tests/ui/pub/pub-ident-struct-4.stderr
@@ -1,12 +1,12 @@
 error: missing `struct` for struct definition
-  --> $DIR/pub-ident-struct-4.rs:3:4
+  --> $DIR/pub-ident-struct-4.rs:4:4
    |
-LL | pub T(#[allow(dead_code)] String);
+LL | pub T(String);
    |    ^
    |
 help: add `struct` here to parse `T` as a public struct
    |
-LL | pub struct T(#[allow(dead_code)] String);
+LL | pub struct T(String);
    |     ++++++
 
 error: aborting due to 1 previous error
diff --git a/tests/ui/regions/regions-issue-21422.rs b/tests/ui/regions/regions-issue-21422.rs
index 54beed9b3ac..67852a6f5de 100644
--- a/tests/ui/regions/regions-issue-21422.rs
+++ b/tests/ui/regions/regions-issue-21422.rs
@@ -5,6 +5,7 @@
 
 //@ pretty-expanded FIXME #23616
 
+#[allow(dead_code)]
 pub struct P<'a> {
     _ptr: *const &'a u8,
 }
diff --git a/tests/ui/structs-enums/newtype-struct-with-dtor.rs b/tests/ui/structs-enums/newtype-struct-with-dtor.rs
index 19672e41c9a..16439a7fedd 100644
--- a/tests/ui/structs-enums/newtype-struct-with-dtor.rs
+++ b/tests/ui/structs-enums/newtype-struct-with-dtor.rs
@@ -3,8 +3,10 @@
 #![allow(unused_variables)]
 //@ pretty-expanded FIXME #23616
 
+#[allow(dead_code)]
 pub struct Fd(u32);
 
+#[allow(dead_code)]
 fn foo(a: u32) {}
 
 impl Drop for Fd {
diff --git a/tests/ui/structs-enums/uninstantiable-struct.rs b/tests/ui/structs-enums/uninstantiable-struct.rs
index 97bc7d8414e..1074dbcd6e6 100644
--- a/tests/ui/structs-enums/uninstantiable-struct.rs
+++ b/tests/ui/structs-enums/uninstantiable-struct.rs
@@ -1,4 +1,5 @@
 //@ run-pass
-pub struct Z(#[allow(dead_code)] &'static Z);
+#[allow(dead_code)]
+pub struct Z(&'static Z);
 
 pub fn main() {}
diff --git a/tests/ui/suggestions/derive-clone-for-eq.fixed b/tests/ui/suggestions/derive-clone-for-eq.fixed
index 4dc362f9478..cf800c6e47d 100644
--- a/tests/ui/suggestions/derive-clone-for-eq.fixed
+++ b/tests/ui/suggestions/derive-clone-for-eq.fixed
@@ -1,6 +1,7 @@
 //@ run-rustfix
 // https://github.com/rust-lang/rust/issues/79076
 
+#[allow(dead_code)]
 #[derive(Clone, Eq)] //~ ERROR [E0277]
 pub struct Struct<T: std::clone::Clone>(T);
 
diff --git a/tests/ui/suggestions/derive-clone-for-eq.rs b/tests/ui/suggestions/derive-clone-for-eq.rs
index b3635000f16..84736426bac 100644
--- a/tests/ui/suggestions/derive-clone-for-eq.rs
+++ b/tests/ui/suggestions/derive-clone-for-eq.rs
@@ -1,6 +1,7 @@
 //@ run-rustfix
 // https://github.com/rust-lang/rust/issues/79076
 
+#[allow(dead_code)]
 #[derive(Clone, Eq)] //~ ERROR [E0277]
 pub struct Struct<T>(T);
 
diff --git a/tests/ui/suggestions/derive-clone-for-eq.stderr b/tests/ui/suggestions/derive-clone-for-eq.stderr
index 6fae6e1316d..54670fbffcf 100644
--- a/tests/ui/suggestions/derive-clone-for-eq.stderr
+++ b/tests/ui/suggestions/derive-clone-for-eq.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `T: Clone` is not satisfied
-  --> $DIR/derive-clone-for-eq.rs:4:17
+  --> $DIR/derive-clone-for-eq.rs:5:17
    |
 LL | #[derive(Clone, Eq)]
    |                 ^^ the trait `Clone` is not implemented for `T`, which is required by `Struct<T>: PartialEq`
    |
 note: required for `Struct<T>` to implement `PartialEq`
-  --> $DIR/derive-clone-for-eq.rs:7:19
+  --> $DIR/derive-clone-for-eq.rs:8:19
    |
 LL | impl<T: Clone, U> PartialEq<U> for Struct<T>
    |         -----     ^^^^^^^^^^^^     ^^^^^^^^^
diff --git a/tests/ui/suggestions/option-content-move.fixed b/tests/ui/suggestions/option-content-move.fixed
index 4a5a9483c20..ef07d55871e 100644
--- a/tests/ui/suggestions/option-content-move.fixed
+++ b/tests/ui/suggestions/option-content-move.fixed
@@ -1,4 +1,5 @@
 //@ run-rustfix
+#[allow(dead_code)]
 pub struct LipogramCorpora {
     selections: Vec<(char, Option<String>)>,
 }
@@ -17,6 +18,7 @@ impl LipogramCorpora {
     }
 }
 
+#[allow(dead_code)]
 pub struct LipogramCorpora2 {
     selections: Vec<(char, Result<String, String>)>,
 }
diff --git a/tests/ui/suggestions/option-content-move.rs b/tests/ui/suggestions/option-content-move.rs
index 90d05c74399..5be6358fd6a 100644
--- a/tests/ui/suggestions/option-content-move.rs
+++ b/tests/ui/suggestions/option-content-move.rs
@@ -1,4 +1,5 @@
 //@ run-rustfix
+#[allow(dead_code)]
 pub struct LipogramCorpora {
     selections: Vec<(char, Option<String>)>,
 }
@@ -17,6 +18,7 @@ impl LipogramCorpora {
     }
 }
 
+#[allow(dead_code)]
 pub struct LipogramCorpora2 {
     selections: Vec<(char, Result<String, String>)>,
 }
diff --git a/tests/ui/suggestions/option-content-move.stderr b/tests/ui/suggestions/option-content-move.stderr
index a382a04344a..b4ec5b180d2 100644
--- a/tests/ui/suggestions/option-content-move.stderr
+++ b/tests/ui/suggestions/option-content-move.stderr
@@ -1,5 +1,5 @@
 error[E0507]: cannot move out of `selection.1` which is behind a shared reference
-  --> $DIR/option-content-move.rs:10:20
+  --> $DIR/option-content-move.rs:11:20
    |
 LL |                 if selection.1.unwrap().contains(selection.0) {
    |                    ^^^^^^^^^^^ -------- `selection.1` moved due to this method call
@@ -19,7 +19,7 @@ LL |                 if selection.1.clone().unwrap().contains(selection.0) {
    |                               ++++++++
 
 error[E0507]: cannot move out of `selection.1` which is behind a shared reference
-  --> $DIR/option-content-move.rs:28:20
+  --> $DIR/option-content-move.rs:30:20
    |
 LL |                 if selection.1.unwrap().contains(selection.0) {
    |                    ^^^^^^^^^^^ -------- `selection.1` moved due to this method call
diff --git a/tests/ui/traits/object/generics.rs b/tests/ui/traits/object/generics.rs
index 462b0bc5bb7..0ae562c0d30 100644
--- a/tests/ui/traits/object/generics.rs
+++ b/tests/ui/traits/object/generics.rs
@@ -7,6 +7,7 @@ pub trait Trait2<A> {
     fn doit(&self) -> A;
 }
 
+#[allow(dead_code)]
 pub struct Impl<A1, A2, A3> {
     m1: marker::PhantomData<(A1,A2,A3)>,
     /*