diff --git a/library/core/src/any.rs b/library/core/src/any.rs
index bb93ea509d8ee..d1c1ae6526b6e 100644
--- a/library/core/src/any.rs
+++ b/library/core/src/any.rs
@@ -866,7 +866,7 @@ where
 ///
 /// A data provider provides values by calling this type's provide methods.
 #[unstable(feature = "provide_any", issue = "96024")]
-#[repr(transparent)]
+#[cfg_attr(not(doc), repr(transparent))] // work around https://github.com/rust-lang/rust/issues/90435
 pub struct Demand<'a>(dyn Erased<'a> + 'a);
 
 impl<'a> Demand<'a> {
diff --git a/library/core/src/ffi/mod.rs b/library/core/src/ffi/mod.rs
index b85894259f1f3..b73abbbaca7ad 100644
--- a/library/core/src/ffi/mod.rs
+++ b/library/core/src/ffi/mod.rs
@@ -203,7 +203,7 @@ mod c_long_definition {
 //     be UB.
 #[doc = include_str!("c_void.md")]
 #[cfg_attr(not(bootstrap), lang = "c_void")]
-#[repr(u8)]
+#[cfg_attr(not(doc), repr(u8))] // work around https://github.com/rust-lang/rust/issues/90435
 #[stable(feature = "core_c_void", since = "1.30.0")]
 pub enum c_void {
     #[unstable(
@@ -244,7 +244,7 @@ impl fmt::Debug for c_void {
     target_os = "uefi",
     windows,
 ))]
-#[repr(transparent)]
+#[cfg_attr(not(doc), repr(transparent))] // work around https://github.com/rust-lang/rust/issues/90435
 #[unstable(
     feature = "c_variadic",
     reason = "the `c_variadic` feature has not been properly tested on \
@@ -296,7 +296,7 @@ impl<'f> fmt::Debug for VaListImpl<'f> {
     not(target_os = "uefi"),
     not(windows),
 ))]
-#[repr(C)]
+#[cfg_attr(not(doc), repr(C))] // work around https://github.com/rust-lang/rust/issues/66401
 #[derive(Debug)]
 #[unstable(
     feature = "c_variadic",
@@ -316,7 +316,7 @@ pub struct VaListImpl<'f> {
 
 /// PowerPC ABI implementation of a `va_list`.
 #[cfg(all(target_arch = "powerpc", not(target_os = "uefi"), not(windows)))]
-#[repr(C)]
+#[cfg_attr(not(doc), repr(C))] // work around https://github.com/rust-lang/rust/issues/66401
 #[derive(Debug)]
 #[unstable(
     feature = "c_variadic",
@@ -336,7 +336,7 @@ pub struct VaListImpl<'f> {
 
 /// s390x ABI implementation of a `va_list`.
 #[cfg(target_arch = "s390x")]
-#[repr(C)]
+#[cfg_attr(not(doc), repr(C))] // work around https://github.com/rust-lang/rust/issues/66401
 #[derive(Debug)]
 #[unstable(
     feature = "c_variadic",
@@ -355,7 +355,7 @@ pub struct VaListImpl<'f> {
 
 /// x86_64 ABI implementation of a `va_list`.
 #[cfg(all(target_arch = "x86_64", not(target_os = "uefi"), not(windows)))]
-#[repr(C)]
+#[cfg_attr(not(doc), repr(C))] // work around https://github.com/rust-lang/rust/issues/66401
 #[derive(Debug)]
 #[unstable(
     feature = "c_variadic",
@@ -373,7 +373,7 @@ pub struct VaListImpl<'f> {
 }
 
 /// A wrapper for a `va_list`
-#[repr(transparent)]
+#[cfg_attr(not(doc), repr(transparent))] // work around https://github.com/rust-lang/rust/issues/90435
 #[derive(Debug)]
 #[unstable(
     feature = "c_variadic",
diff --git a/library/core/src/task/wake.rs b/library/core/src/task/wake.rs
index 808825326aef5..7043ab5ff2b41 100644
--- a/library/core/src/task/wake.rs
+++ b/library/core/src/task/wake.rs
@@ -232,7 +232,7 @@ impl fmt::Debug for Context<'_> {
 ///
 /// [`Future::poll()`]: core::future::Future::poll
 /// [`Poll::Pending`]: core::task::Poll::Pending
-#[repr(transparent)]
+#[cfg_attr(not(doc), repr(transparent))] // work around https://github.com/rust-lang/rust/issues/66401
 #[stable(feature = "futures_api", since = "1.36.0")]
 pub struct Waker {
     waker: RawWaker,
diff --git a/library/portable-simd/crates/core_simd/src/masks.rs b/library/portable-simd/crates/core_simd/src/masks.rs
index e58df80fca8b5..e0f3c7beef689 100644
--- a/library/portable-simd/crates/core_simd/src/masks.rs
+++ b/library/portable-simd/crates/core_simd/src/masks.rs
@@ -88,7 +88,7 @@ impl_element! { isize }
 /// The layout of this type is unspecified, and may change between platforms
 /// and/or Rust versions, and code should not assume that it is equivalent to
 /// `[T; LANES]`.
-#[repr(transparent)]
+#[cfg_attr(not(doc), repr(transparent))] // work around https://github.com/rust-lang/rust/issues/90435
 pub struct Mask<T, const LANES: usize>(mask_impl::Mask<T, LANES>)
 where
     T: MaskElement,