diff --git a/gcc/rust/util/rust-attributes.cc b/gcc/rust/util/rust-attributes.cc
index bf7f3d9827d6..a58336ef9e3d 100644
--- a/gcc/rust/util/rust-attributes.cc
+++ b/gcc/rust/util/rust-attributes.cc
@@ -885,6 +885,13 @@ AttributeChecker::visit (AST::Function &fun)
 			   "must be of the form: %<#[target_feature(enable = "
 			   "\"name\")]%>");
 	    }
+	  else if (!fun.get_qualifiers ().is_unsafe ())
+	    {
+	      rust_error_at (
+		attribute.get_locus (),
+		"the %<#[target_feature]%> attribute can only be applied "
+		"to %<unsafe%> functions");
+	    }
 	}
       else if (result.name == "no_mangle")
 	{
diff --git a/gcc/testsuite/rust/compile/issue-4234.rs b/gcc/testsuite/rust/compile/issue-4234.rs
new file mode 100644
index 000000000000..bb60e35ace64
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-4234.rs
@@ -0,0 +1,3 @@
+// { dg-options "-w" }
+#[target_feature(sse)] // { dg-error "attribute can only be applied" }
+fn foo() {}
\ No newline at end of file
diff --git a/gcc/testsuite/rust/compile/unsafe11.rs b/gcc/testsuite/rust/compile/unsafe11.rs
index c87902fcd5f1..e6657a6d6cbf 100644
--- a/gcc/testsuite/rust/compile/unsafe11.rs
+++ b/gcc/testsuite/rust/compile/unsafe11.rs
@@ -1,8 +1,9 @@
 #[target_feature(sse)]
-fn foo() {
+unsafe fn foo() {
     let a: usize = 0;
 }
 
 fn main() {
-    foo() // { dg-error "requires unsafe function or block" }
+    foo(); // { dg-error "requires unsafe function or block" }
+    unsafe { foo(); }
 }