Auto merge of rust-lang#120558 - oli-obk:missing_impl_item_ice, r=estebank

Stop bailing out from compilation just because there were incoherent traits

fixes rust-lang#120343

but also has a lot of "type annotations needed" fallout. Some are fixed in the second commit.

Author: bors

core/src/primitive_docs.rs

@@ -448,22 +448,6 @@ mod prim_unit {}
 #[doc(hidden)]
 impl () {}
 
-// Fake impl that's only really used for docs.
-#[cfg(doc)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Clone for () {
-    fn clone(&self) -> Self {
-        loop {}
-    }
-}
-
-// Fake impl that's only really used for docs.
-#[cfg(doc)]
-#[stable(feature = "rust1", since = "1.0.0")]
-impl Copy for () {
-    // empty
-}
-
 #[rustc_doc_primitive = "pointer"]
 #[doc(alias = "ptr")]
 #[doc(alias = "*")]
@@ -1690,23 +1674,3 @@ mod prim_fn {}
 // See src/librustdoc/passes/collect_trait_impls.rs:collect_trait_impls
 #[doc(hidden)]
 impl<Ret, T> fn(T) -> Ret {}
-
-// Fake impl that's only really used for docs.
-#[cfg(doc)]
-#[stable(feature = "rust1", since = "1.0.0")]
-#[doc(fake_variadic)]
-/// This trait is implemented on function pointers with any number of arguments.
-impl<Ret, T> Clone for fn(T) -> Ret {
-    fn clone(&self) -> Self {
-        loop {}
-    }
-}
-
-// Fake impl that's only really used for docs.
-#[cfg(doc)]
-#[stable(feature = "rust1", since = "1.0.0")]
-#[doc(fake_variadic)]
-/// This trait is implemented on function pointers with any number of arguments.
-impl<Ret, T> Copy for fn(T) -> Ret {
-    // empty
-}