pin_init: allow nonstandard_style for generated identifiers

Allows `nonstandard_style` lint on locally generated identifiers in
`pin_init!`.

Since the same warning will be reported by the compiler on the struct
definition, having the extra warning emitted at the macro call site is
unnecessary and confusing.

Suggested-by: Gary Guo <gary@garyguo.net>
Link: #125
Signed-off-by: Mirko Adzic <adzicmirko97@gmail.com>

Author: Mirko-A

internal/src/pin_data.rs

@@ -164,7 +164,10 @@ fn generate_unpin_impl(
     quote! {
         // This struct will be used for the unpin analysis. It is needed, because only structurally
         // pinned fields are relevant whether the struct should implement `Unpin`.
-        #[allow(dead_code)] // The fields below are never used.
+        #[allow(
+            dead_code, // The fields below are never used.
+            nonstandard_style // The warning will be emitted on the struct definition.
+        )]
         struct __Unpin #generics_with_pin_lt
         #where_token
             #predicates
@@ -302,7 +305,9 @@ fn generate_projections(
     let docs = format!(" Pin-projections of [`{ident}`]");
     quote! {
         #[doc = #docs]
-        #[allow(dead_code)]
+        // Allow `nonstandard_style` since the same warning will be emitted on
+        // the struct definition.
+        #[allow(dead_code, nonstandard_style)]
         #[doc(hidden)]
         #vis struct #projection #generics_with_pin_lt {
             #(#fields_decl)*
@@ -395,6 +400,9 @@ fn generate_the_pin_data(
             ///   to deallocate.
             #pin_safety
             #(#attrs)*
+            // Allow `nonstandard_style` since the same warning will be emitted on
+            // the struct definition.
+            #[allow(nonstandard_style)]
             #vis unsafe fn #ident<E>(
                 self,
                 slot: *mut #ty,

tests/ui/expand/many_generics.expanded.rs

@@ -13,7 +13,7 @@ where
     _pin: PhantomPinned,
 }
 /// Pin-projections of [`Foo`]
-#[allow(dead_code)]
+#[allow(dead_code, nonstandard_style)]
 #[doc(hidden)]
 struct FooProjection<
     '__pin,
@@ -92,6 +92,7 @@ const _: () = {
         /// - `slot` is a valid pointer to uninitialized memory.
         /// - the caller does not touch `slot` when `Err` is returned, they are only permitted
         ///   to deallocate.
+        #[allow(nonstandard_style)]
         unsafe fn array<E>(
             self,
             slot: *mut [u8; 1024 * 1024],
@@ -113,6 +114,7 @@ const _: () = {
         /// - `slot` is a valid pointer to uninitialized memory.
         /// - the caller does not touch `slot` when `Err` is returned, they are only permitted
         ///   to deallocate.
+        #[allow(nonstandard_style)]
         unsafe fn r<E>(
             self,
             slot: *mut &'b mut [&'a mut T; SIZE],
@@ -135,6 +137,7 @@ const _: () = {
         /// - the caller does not touch `slot` when `Err` is returned, they are only permitted
         ///   to deallocate.
         /// - `slot` will not move until it is dropped, i.e. it will be pinned.
+        #[allow(nonstandard_style)]
         unsafe fn _pin<E>(
             self,
             slot: *mut PhantomPinned,
@@ -179,7 +182,7 @@ const _: () = {
     {
         type Datee = Foo<'a, 'b, T, SIZE>;
     }
-    #[allow(dead_code)]
+    #[allow(dead_code, nonstandard_style)]
     struct __Unpin<'__pin, 'a, 'b: 'a, T: Bar<'b> + ?Sized + 'a, const SIZE: usize = 0>
     where
         T: Bar<'a, 1>,

tests/ui/expand/pin-data.expanded.rs

@@ -5,7 +5,7 @@ struct Foo {
     _pin: PhantomPinned,
 }
 /// Pin-projections of [`Foo`]
-#[allow(dead_code)]
+#[allow(dead_code, nonstandard_style)]
 #[doc(hidden)]
 struct FooProjection<'__pin> {
     array: &'__pin mut [u8; 1024 * 1024],
@@ -51,6 +51,7 @@ const _: () = {
         /// - `slot` is a valid pointer to uninitialized memory.
         /// - the caller does not touch `slot` when `Err` is returned, they are only permitted
         ///   to deallocate.
+        #[allow(nonstandard_style)]
         unsafe fn array<E>(
             self,
             slot: *mut [u8; 1024 * 1024],
@@ -73,6 +74,7 @@ const _: () = {
         /// - the caller does not touch `slot` when `Err` is returned, they are only permitted
         ///   to deallocate.
         /// - `slot` will not move until it is dropped, i.e. it will be pinned.
+        #[allow(nonstandard_style)]
         unsafe fn _pin<E>(
             self,
             slot: *mut PhantomPinned,
@@ -101,7 +103,7 @@ const _: () = {
     unsafe impl ::pin_init::__internal::PinData for __ThePinData {
         type Datee = Foo;
     }
-    #[allow(dead_code)]
+    #[allow(dead_code, nonstandard_style)]
     struct __Unpin<'__pin> {
         __phantom_pin: ::core::marker::PhantomData<fn(&'__pin ()) -> &'__pin ()>,
         __phantom: ::core::marker::PhantomData<fn(Foo) -> Foo>,

tests/ui/expand/pinned_drop.expanded.rs

@@ -5,7 +5,7 @@ struct Foo {
     _pin: PhantomPinned,
 }
 /// Pin-projections of [`Foo`]
-#[allow(dead_code)]
+#[allow(dead_code, nonstandard_style)]
 #[doc(hidden)]
 struct FooProjection<'__pin> {
     array: &'__pin mut [u8; 1024 * 1024],
@@ -51,6 +51,7 @@ const _: () = {
         /// - `slot` is a valid pointer to uninitialized memory.
         /// - the caller does not touch `slot` when `Err` is returned, they are only permitted
         ///   to deallocate.
+        #[allow(nonstandard_style)]
         unsafe fn array<E>(
             self,
             slot: *mut [u8; 1024 * 1024],
@@ -73,6 +74,7 @@ const _: () = {
         /// - the caller does not touch `slot` when `Err` is returned, they are only permitted
         ///   to deallocate.
         /// - `slot` will not move until it is dropped, i.e. it will be pinned.
+        #[allow(nonstandard_style)]
         unsafe fn _pin<E>(
             self,
             slot: *mut PhantomPinned,
@@ -101,7 +103,7 @@ const _: () = {
     unsafe impl ::pin_init::__internal::PinData for __ThePinData {
         type Datee = Foo;
     }
-    #[allow(dead_code)]
+    #[allow(dead_code, nonstandard_style)]
     struct __Unpin<'__pin> {
         __phantom_pin: ::core::marker::PhantomData<fn(&'__pin ()) -> &'__pin ()>,
         __phantom: ::core::marker::PhantomData<fn(Foo) -> Foo>,