1 files changed, 56 insertions, 8 deletions

diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index f00165cd3..e5dfda24d 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -3094,7 +3094,7 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust
+    /// ```rust,compile_fail
     /// #![cfg_attr(debug_assertions, crate_type = "lib")]
     /// ```
     ///
@@ -3114,7 +3114,7 @@ declare_lint! {
     /// rustc instead of `#![cfg_attr(..., crate_type = "...")]` and
     /// `--crate-name` instead of `#![cfg_attr(..., crate_name = "...")]`.
     pub DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
-    Warn,
+    Deny,
     "detects usage of `#![cfg_attr(..., crate_type/crate_name = \"...\")]`",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #91632 <https://github.com/rust-lang/rust/issues/91632>",
@@ -3206,12 +3206,62 @@ declare_lint! {
     /// [future-incompatible]: ../index.md#future-incompatible-lints
     pub REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS,
     Warn,
-    "tranparent type contains an external ZST that is marked #[non_exhaustive] or contains private fields",
+    "transparent type contains an external ZST that is marked #[non_exhaustive] or contains private fields",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #78586 <https://github.com/rust-lang/rust/issues/78586>",
     };
 }
 
+declare_lint! {
+    /// The `unstable_syntax_pre_expansion` lint detects the use of unstable
+    /// syntax that is discarded during attribute expansion.
+    ///
+    /// ### Example
+    ///
+    /// ```rust
+    /// #[cfg(FALSE)]
+    /// macro foo() {}
+    /// ```
+    ///
+    /// {{produces}}
+    ///
+    /// ### Explanation
+    ///
+    /// The input to active attributes such as `#[cfg]` or procedural macro
+    /// attributes is required to be valid syntax. Previously, the compiler only
+    /// gated the use of unstable syntax features after resolving `#[cfg]` gates
+    /// and expanding procedural macros.
+    ///
+    /// To avoid relying on unstable syntax, move the use of unstable syntax
+    /// into a position where the compiler does not parse the syntax, such as a
+    /// functionlike macro.
+    ///
+    /// ```rust
+    /// # #![deny(unstable_syntax_pre_expansion)]
+    ///
+    /// macro_rules! identity {
+    ///    ( $($tokens:tt)* ) => { $($tokens)* }
+    /// }
+    ///
+    /// #[cfg(FALSE)]
+    /// identity! {
+    ///    macro foo() {}
+    /// }
+    /// ```
+    ///
+    /// This is a [future-incompatible] lint to transition this
+    /// to a hard error in the future. See [issue #65860] for more details.
+    ///
+    /// [issue #65860]: https://github.com/rust-lang/rust/issues/65860
+    /// [future-incompatible]: ../index.md#future-incompatible-lints
+    pub UNSTABLE_SYNTAX_PRE_EXPANSION,
+    Warn,
+    "unstable syntax can change at any point in the future, causing a hard error!",
+    @future_incompatible = FutureIncompatibleInfo {
+        reference: "issue #65860 <https://github.com/rust-lang/rust/issues/65860>",
+    };
+}
+
 declare_lint_pass! {
     /// Does nothing as a lint pass, but registers some `Lint`s
     /// that are used by other parts of the compiler.
@@ -3280,6 +3330,7 @@ declare_lint_pass! {
         POINTER_STRUCTURAL_MATCH,
         NONTRIVIAL_STRUCTURAL_MATCH,
         SOFT_UNSTABLE,
+        UNSTABLE_SYNTAX_PRE_EXPANSION,
         INLINE_NO_SANITIZE,
         BAD_ASM_STYLE,
         ASM_SUB_REGISTER,
@@ -3314,7 +3365,6 @@ declare_lint_pass! {
         DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
         DUPLICATE_MACRO_ATTRIBUTES,
         SUSPICIOUS_AUTO_TRAIT_IMPLS,
-        UNEXPECTED_CFGS,
         DEPRECATED_WHERE_CLAUSE_LOCATION,
         TEST_UNSTABLE_LINT,
         FFI_UNWIND_CALLS,
@@ -3357,7 +3407,7 @@ declare_lint! {
     ///
     /// ### Example of drop reorder
     ///
-    /// ```rust,compile_fail
+    /// ```rust,edition2018,compile_fail
     /// #![deny(rust_2021_incompatible_closure_captures)]
     /// # #![allow(unused)]
     ///
@@ -3393,7 +3443,7 @@ declare_lint! {
     ///
     /// ### Example of auto-trait
     ///
-    /// ```rust,compile_fail
+    /// ```rust,edition2018,compile_fail
     /// #![deny(rust_2021_incompatible_closure_captures)]
     /// use std::thread;
     ///
@@ -3938,8 +3988,6 @@ declare_lint! {
     /// ### Example
     ///
     /// ```rust
-    /// #![feature(generic_associated_types)]
-    ///
     /// trait Trait {
     ///   type Assoc<'a> where Self: 'a;
     /// }