gccrs: add missing coercion site code generation for block tail

Fixes #2179

gcc/rust/ChangeLog:

	* backend/rust-compile-base.cc (HIRCompileBase::compile_function_body):
	add missing coercion_site codegen

gcc/testsuite/ChangeLog:

	* rust/execute/torture/issue-2179.rs: New test.

Signed-off-by: Philip Herron <herron.philip@googlemail.com>

2 files changed, 42 insertions, 0 deletions

diff --git a/gcc/rust/backend/rust-compile-base.cc b/gcc/rust/backend/rust-compile-base.cc
index 4a7e04b..9d27e23 100644
--- a/gcc/rust/backend/rust-compile-base.cc
+++ b/gcc/rust/backend/rust-compile-base.cc
@@ -489,6 +489,19 @@ HIRCompileBase::compile_function_body (tree fndecl,
       // we can only return this if non unit value return type
       if (!fn_return_ty->is_unit ())
 	{
+	  HirId id = function_body.get_mappings ().get_hirid ();
+	  Location lvalue_locus = function_body.get_locus ();
+	  Location rvalue_locus = locus;
+
+	  TyTy::BaseType *expected = fn_return_ty;
+	  TyTy::BaseType *actual = nullptr;
+	  bool ok = ctx->get_tyctx ()->lookup_type (
+	    function_body.expr->get_mappings ().get_hirid (), &actual);
+	  rust_assert (ok);
+
+	  return_value = coercion_site (id, return_value, actual, expected,
+					lvalue_locus, rvalue_locus);
+
 	  tree return_stmt
 	    = ctx->get_backend ()->return_statement (fndecl, return_value,
 						     locus);
diff --git a/gcc/testsuite/rust/execute/torture/issue-2179.rs b/gcc/testsuite/rust/execute/torture/issue-2179.rs
new file mode 100644
index 0000000..53bacaa
--- /dev/null
+++ b/gcc/testsuite/rust/execute/torture/issue-2179.rs
@@ -0,0 +1,29 @@
+// { dg-output "123\n" }
+trait A {
+    fn get_int(&self) -> i32;
+}
+
+impl A for i32 {
+    fn get_int(&self) -> i32 {
+        *self
+    }
+}
+
+fn get_dyn_a(x: &i32) -> &dyn A {
+    x
+}
+
+extern "C" {
+    fn printf(s: *const i8, ...) -> i32;
+}
+
+fn main() -> i32 {
+    let x = 123;
+    let y = get_dyn_a(&x);
+    let value = y.get_int();
+    let fmt_string = "%d\n\0" as *const str as *const i8;
+    unsafe {
+        printf(fmt_string, value);
+    }
+    return 0;
+}