fix: let non_canonical_impls skip proc marco

Author: WeiTheShinobi

clippy_lints/src/non_canonical_impls.rs

@@ -128,6 +128,11 @@ impl LateLintPass<'_> for NonCanonicalImpls {
         let ExprKind::Block(block, ..) = body.value.kind else {
             return;
         };
+        if let Some(expr) = block.expr
+            && expr.span.from_expansion()
+        {
+            return;
+        }
 
         if cx.tcx.is_diagnostic_item(sym::Clone, trait_impl.def_id)
             && let Some(copy_def_id) = cx.tcx.get_diagnostic_item(sym::Copy)

tests/ui/auxiliary/proc_macro_derive.rs

@@ -169,3 +169,17 @@ pub fn derive_ignored_unit_pattern(_: TokenStream) -> TokenStream {
         }
     }
 }
+
+#[proc_macro_derive(NonCanonicalClone)]
+pub fn non_canonical_clone_derive(_: TokenStream) -> TokenStream {
+    quote! {
+        struct NonCanonicalClone;
+        impl Clone for NonCanonicalClone {
+            fn clone(&self) -> Self {
+                let a = *self;
+                a
+            }
+        }
+        impl Copy for NonCanonicalClone {}
+    }
+}

tests/ui/non_canonical_clone_impl.fixed

@@ -1,3 +1,4 @@
+//@aux-build:proc_macro_derive.rs
 #![allow(clippy::clone_on_copy, unused)]
 #![allow(clippy::assigning_clones)]
 #![no_main]
@@ -95,3 +96,7 @@ impl<A: Copy> Clone for Uwu<A> {
 }
 
 impl<A: std::fmt::Debug + Copy + Clone> Copy for Uwu<A> {}
+
+// should skip proc macros, see https://github.com/rust-lang/rust-clippy/issues/12788
+#[derive(proc_macro_derive::NonCanonicalClone)]
+pub struct G;

tests/ui/non_canonical_clone_impl.rs

@@ -1,3 +1,4 @@
+//@aux-build:proc_macro_derive.rs
 #![allow(clippy::clone_on_copy, unused)]
 #![allow(clippy::assigning_clones)]
 #![no_main]
@@ -105,3 +106,7 @@ impl<A: Copy> Clone for Uwu<A> {
 }
 
 impl<A: std::fmt::Debug + Copy + Clone> Copy for Uwu<A> {}
+
+// should skip proc macros, see https://github.com/rust-lang/rust-clippy/issues/12788
+#[derive(proc_macro_derive::NonCanonicalClone)]
+pub struct G;

tests/ui/non_canonical_clone_impl.stderr

@@ -1,5 +1,5 @@
 error: non-canonical implementation of `clone` on a `Copy` type
-  --> tests/ui/non_canonical_clone_impl.rs:10:29
+  --> tests/ui/non_canonical_clone_impl.rs:11:29
    |
 LL |       fn clone(&self) -> Self {
    |  _____________________________^
@@ -11,7 +11,7 @@ LL | |     }
    = help: to override `-D warnings` add `#[allow(clippy::non_canonical_clone_impl)]`
 
 error: unnecessary implementation of `clone_from` on a `Copy` type
-  --> tests/ui/non_canonical_clone_impl.rs:14:5
+  --> tests/ui/non_canonical_clone_impl.rs:15:5
    |
 LL | /     fn clone_from(&mut self, source: &Self) {
 LL | |         source.clone();
@@ -20,7 +20,7 @@ LL | |     }
    | |_____^ help: remove it
 
 error: non-canonical implementation of `clone` on a `Copy` type
-  --> tests/ui/non_canonical_clone_impl.rs:81:29
+  --> tests/ui/non_canonical_clone_impl.rs:82:29
    |
 LL |       fn clone(&self) -> Self {
    |  _____________________________^
@@ -29,7 +29,7 @@ LL | |     }
    | |_____^ help: change this to: `{ *self }`
 
 error: unnecessary implementation of `clone_from` on a `Copy` type
-  --> tests/ui/non_canonical_clone_impl.rs:85:5
+  --> tests/ui/non_canonical_clone_impl.rs:86:5
    |
 LL | /     fn clone_from(&mut self, source: &Self) {
 LL | |         source.clone();