gccrs: derive(Hash): Add implementation.

gcc/rust/ChangeLog:

	* Make-lang.in: Compile it.
	* expand/rust-derive.cc (DeriveVisitor::derive): Call it.
	* expand/rust-derive-hash.cc: New file.
	* expand/rust-derive-hash.h: New file.

gcc/testsuite/ChangeLog:

	* rust/compile/derive-hash1.rs: New test.
	* rust/compile/nr2/exclude: Add testcase to exclusion list.

2 files changed, 92 insertions, 0 deletions

diff --git a/gcc/testsuite/rust/compile/derive-hash1.rs b/gcc/testsuite/rust/compile/derive-hash1.rs
new file mode 100644
index 0000000..80e1e2d
--- /dev/null
+++ b/gcc/testsuite/rust/compile/derive-hash1.rs
@@ -0,0 +1,91 @@
+#![feature(intrinsics)]
+
+#[lang = "sized"]
+trait Sized {}
+
+pub mod core {
+    pub mod intrinsics {
+        #[lang = "discriminant_kind"]
+        pub trait DiscriminantKind {
+            #[lang = "discriminant_type"]
+            type Discriminant;
+        }
+
+        extern "rust-intrinsic" {
+            pub fn discriminant_value<T>(v: &T) -> <T as DiscriminantKind>::Discriminant;
+        }
+    }
+
+    pub mod hash {
+        pub trait Hasher {}
+
+        pub trait Hash {
+            /// Feeds this value into the given [`Hasher`].
+            ///
+            /// # Examples
+            ///
+            /// ```
+            /// use std::collections::hash_map::DefaultHasher;
+            /// use std::hash::{Hash, Hasher};
+            ///
+            /// let mut hasher = DefaultHasher::new();
+            /// 7920.hash(&mut hasher);
+            /// println!("Hash is {:x}!", hasher.finish());
+            /// ```
+            #[stable(feature = "rust1", since = "1.0.0")]
+            fn hash<H: Hasher>(&self, state: &mut H);
+
+            /// Feeds a slice of this type into the given [`Hasher`].
+            ///
+            /// # Examples
+            ///
+            /// ```
+            /// use std::collections::hash_map::DefaultHasher;
+            /// use std::hash::{Hash, Hasher};
+            ///
+            /// let mut hasher = DefaultHasher::new();
+            /// let numbers = [6, 28, 496, 8128];
+            /// Hash::hash_slice(&numbers, &mut hasher);
+            /// println!("Hash is {:x}!", hasher.finish());
+            /// ```
+            #[stable(feature = "hash_slice", since = "1.3.0")]
+            fn hash_slice<H: Hasher>(data: &[Self], state: &mut H)
+            where
+                Self: Sized,
+            {
+                // for piece in data {
+                //     piece.hash(state);
+                // }
+            }
+        }
+    }
+}
+
+impl core::hash::Hash for i32 {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {}
+}
+
+impl core::hash::Hash for i64 {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {}
+}
+
+// for the discriminant value
+impl core::hash::Hash for isize {
+    fn hash<H: core::hash::Hasher>(&self, state: &mut H) {}
+}
+
+#[derive(Hash)]
+struct Foo { // { dg-warning "never constructed" }
+    a: i32,
+    b: i32,
+}
+
+#[derive(Hash)]
+struct Bar(i32, i64); // { dg-warning "never constructed" }
+
+#[derive(Hash)]
+enum Baz {
+    A,
+    B(i32),
+    C { a: i64 }
+}
diff --git a/gcc/testsuite/rust/compile/nr2/exclude b/gcc/testsuite/rust/compile/nr2/exclude
index 26b830e..345b1d5 100644
--- a/gcc/testsuite/rust/compile/nr2/exclude
+++ b/gcc/testsuite/rust/compile/nr2/exclude
@@ -77,4 +77,5 @@ for-loop2.rs
 issue-3403.rs
 derive-eq-invalid.rs
 derive-partialeq1.rs
+derive-hash1.rs
 # please don't delete the trailing newline