Deprecate Rust targets lower or equal than `1.30` (#2356)

3 files changed, 21 insertions, 10 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0664a6d8..387d8e94 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -159,6 +159,9 @@
 
  * Replace the `name: &str` argument for `ParseCallbacks::add_derives` by
    `info: DeriveInfo`.
+ * All the rust targets equal or lower than `1.30` are being deprecated and
+   will be removed in the future. If you have a good reason to use any of these
+   targets, please report it in the issue tracker.
 
 ## Removed
 
diff --git a/bindgen/features.rs b/bindgen/features.rs
index 9f6535aa..4fee5d63 100644
--- a/bindgen/features.rs
+++ b/bindgen/features.rs
@@ -2,6 +2,7 @@
 
 #![deny(missing_docs)]
 #![deny(unused_extern_crates)]
+#![allow(deprecated)]
 
 use std::io;
 use std::str::FromStr;
@@ -86,35 +87,35 @@ macro_rules! rust_target_base {
     ( $x_macro:ident ) => {
         $x_macro!(
             /// Rust stable 1.0
-            => Stable_1_0 => 1.0;
+            #[deprecated = "This rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues"] => Stable_1_0 => 1.0;
             /// Rust stable 1.17
             ///  * Static lifetime elision ([RFC 1623](https://github.com/rust-lang/rfcs/blob/master/text/1623-static.md))
-            => Stable_1_17 => 1.17;
+            #[deprecated = "This rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues"] => Stable_1_17 => 1.17;
             /// Rust stable 1.19
             ///  * Untagged unions ([RFC 1444](https://github.com/rust-lang/rfcs/blob/master/text/1444-union.md))
-            => Stable_1_19 => 1.19;
+            #[deprecated = "This rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues"] => Stable_1_19 => 1.19;
             /// Rust stable 1.20
             ///  * Associated constants ([PR](https://github.com/rust-lang/rust/pull/42809))
-            => Stable_1_20 => 1.20;
+            #[deprecated = "This rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues"] => Stable_1_20 => 1.20;
             /// Rust stable 1.21
             ///  * Builtin impls for `Clone` ([PR](https://github.com/rust-lang/rust/pull/43690))
-            => Stable_1_21 => 1.21;
+            #[deprecated = "This rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues"] => Stable_1_21 => 1.21;
             /// Rust stable 1.25
             ///  * `repr(align)` ([PR](https://github.com/rust-lang/rust/pull/47006))
-            => Stable_1_25 => 1.25;
+            #[deprecated = "This rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues"] => Stable_1_25 => 1.25;
             /// Rust stable 1.26
             ///  * [i128 / u128 support](https://doc.rust-lang.org/std/primitive.i128.html)
-            => Stable_1_26 => 1.26;
+            #[deprecated = "This rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues"] => Stable_1_26 => 1.26;
             /// Rust stable 1.27
             ///  * `must_use` attribute on functions ([PR](https://github.com/rust-lang/rust/pull/48925))
-            => Stable_1_27 => 1.27;
+            #[deprecated = "This rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues"] => Stable_1_27 => 1.27;
             /// Rust stable 1.28
             ///  * `repr(transparent)` ([PR](https://github.com/rust-lang/rust/pull/51562))
-            => Stable_1_28 => 1.28;
+            #[deprecated = "This rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues"] => Stable_1_28 => 1.28;
             /// Rust stable 1.30
             ///  * `const fn` support for limited cases ([PR](https://github.com/rust-lang/rust/pull/54835/)
             /// *  [c_void available in core](https://doc.rust-lang.org/core/ffi/enum.c_void.html)
-            => Stable_1_30 => 1.30;
+            #[deprecated = "This rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues"] => Stable_1_30 => 1.30;
             /// Rust stable 1.33
             ///  * repr(packed(N)) ([PR](https://github.com/rust-lang/rust/pull/57049))
             => Stable_1_33 => 1.33;
diff --git a/bindgen/lib.rs b/bindgen/lib.rs
index 53bbd887..4b71fb97 100644
--- a/bindgen/lib.rs
+++ b/bindgen/lib.rs
@@ -731,6 +731,13 @@ impl Builder {
     ///
     /// The default is the latest stable Rust version
     pub fn rust_target(mut self, rust_target: RustTarget) -> Self {
+        #[allow(deprecated)]
+        if rust_target <= RustTarget::Stable_1_30 {
+            warn!(
+                "The {} rust target is deprecated. If you have a good reason to use this target please report it at https://github.com/rust-lang/rust-bindgen/issues",
+                String::from(rust_target)
+            );
+        }
         self.options.set_rust_target(rust_target);
         self
     }