Add `wasm_c_abi` `future-incompat` lint

1 files changed, 39 insertions, 0 deletions

diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 6506aa33431..3391cd8e40a 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -130,6 +130,7 @@ declare_lint_pass! {
         UNUSED_VARIABLES,
         USELESS_DEPRECATED,
         WARNINGS,
+        WASM_C_ABI,
         WHERE_CLAUSES_OBJECT_SAFETY,
         WRITES_THROUGH_IMMUTABLE_POINTER,
         // tidy-alphabetical-end
@@ -4564,3 +4565,41 @@ declare_lint! {
         reference: "issue #120192 <https://github.com/rust-lang/rust/issues/120192>",
     };
 }
+
+declare_lint! {
+    /// The `wasm_c_abi` lint detects crate dependencies that are incompatible
+    /// with future versions of Rust that will emit spec-compliant C ABI.
+    ///
+    /// ### Example
+    ///
+    /// ```rust,ignore (needs extern crate)
+    /// #![deny(wasm_c_abi)]
+    /// ```
+    ///
+    /// This will produce:
+    ///
+    /// ```text
+    /// error: the following packages contain code that will be rejected by a future version of Rust: wasm-bindgen v0.2.87
+    ///   |
+    /// note: the lint level is defined here
+    ///  --> src/lib.rs:1:9
+    ///   |
+    /// 1 | #![deny(wasm_c_abi)]
+    ///   |         ^^^^^^^^^^
+    /// ```
+    ///
+    /// ### Explanation
+    ///
+    /// Rust has historically emitted non-spec-compliant C ABI. This has caused
+    /// incompatibilities between other compilers and Wasm targets. In a future
+    /// version of Rust this will be fixed and therefore dependencies relying
+    /// on the non-spec-compliant C ABI will stop functioning.
+    pub WASM_C_ABI,
+    Warn,
+    "detects dependencies that are incompatible with the Wasm C ABI",
+    @future_incompatible = FutureIncompatibleInfo {
+        reason: FutureIncompatibilityReason::FutureReleaseErrorReportInDeps,
+        reference: "issue #71871 <https://github.com/rust-lang/rust/issues/71871>",
+    };
+    crate_level_only
+}