gccrs: derive: Add proper derive(Clone) for unions

gcc/rust/ChangeLog:

	* ast/rust-ast-builder.cc (AstBuilder::struct_expr_struct): New function.
	(AstBuilder::let): Likewise.
	(AstBuilder::struct_expr): Likewise.
	(AstBuilder::struct_expr_field): Likewise.
	(AstBuilder::field_access): Likewise.
	(AstBuilder::wildcard): Likewise.
	* ast/rust-ast-builder.h: Likewise.
	* expand/rust-derive-clone.cc (DeriveClone::visit_union): Implement
	properly.

gcc/testsuite/ChangeLog:

	* rust/compile/derive_macro4.rs: New test.
	* rust/compile/derive_macro6.rs: New test.

2 files changed, 37 insertions, 0 deletions

diff --git a/gcc/testsuite/rust/compile/derive_macro4.rs b/gcc/testsuite/rust/compile/derive_macro4.rs
new file mode 100644
index 0000000..564555f
--- /dev/null
+++ b/gcc/testsuite/rust/compile/derive_macro4.rs
@@ -0,0 +1,16 @@
+pub trait Copy {}
+pub trait Clone {
+    fn clone(&self) -> Self;
+}
+
+struct PhantomData<T>;
+
+pub struct AssertParamIsCopy<T: Copy> {
+    _field: PhantomData<T>,
+}
+
+#[derive(Clone)] // { dg-error "bounds not satisfied for U .Copy. is not satisfied" }
+union U {
+    i: i32,
+    f: f64,
+}
diff --git a/gcc/testsuite/rust/compile/derive_macro6.rs b/gcc/testsuite/rust/compile/derive_macro6.rs
new file mode 100644
index 0000000..0254754
--- /dev/null
+++ b/gcc/testsuite/rust/compile/derive_macro6.rs
@@ -0,0 +1,21 @@
+pub trait Copy {}
+pub trait Clone {
+    fn clone(&self) -> Self;
+}
+
+#[lang = "phantom_data"]
+pub struct PhantomData<T>;
+
+pub struct AssertParamIsCopy<T: Copy> {
+    pub _field: PhantomData<T>,
+}
+
+impl Copy for i32 {}
+impl Copy for i64 {}
+impl Copy for U {}
+
+#[derive(Clone)]
+union U {
+    i: i32,
+    f: f64,
+}