Add UI test for duplicate asm! options warning

Author: camelid

src/test/ui/asm/duplicate-options.rs

@@ -0,0 +1,19 @@
+// only-x86_64
+// build-pass
+
+#![feature(asm)]
+
+fn main() {
+    unsafe {
+        asm!("", options(nomem, nomem));
+        //~^ WARNING the `nomem` option was already provided
+        asm!("", options(att_syntax, att_syntax));
+        //~^ WARNING the `att_syntax` option was already provided
+        asm!("", options(nostack, att_syntax), options(nostack));
+        //~^ WARNING the `nostack` option was already provided
+        asm!("", options(nostack, nostack), options(nostack), options(nostack));
+        //~^ WARNING the `nostack` option was already provided
+        //~| WARNING the `nostack` option was already provided
+        //~| WARNING the `nostack` option was already provided
+    }
+}

src/test/ui/asm/duplicate-options.stderr

@@ -0,0 +1,38 @@
+warning: the `nomem` option was already provided
+  --> $DIR/duplicate-options.rs:8:33
+   |
+LL |         asm!("", options(nomem, nomem));
+   |                                 ^^^^^ help: remove this option
+
+warning: the `att_syntax` option was already provided
+  --> $DIR/duplicate-options.rs:10:38
+   |
+LL |         asm!("", options(att_syntax, att_syntax));
+   |                                      ^^^^^^^^^^ help: remove this option
+
+warning: the `nostack` option was already provided
+  --> $DIR/duplicate-options.rs:12:56
+   |
+LL |         asm!("", options(nostack, att_syntax), options(nostack));
+   |                                                        ^^^^^^^ help: remove this option
+
+warning: the `nostack` option was already provided
+  --> $DIR/duplicate-options.rs:14:35
+   |
+LL |         asm!("", options(nostack, nostack), options(nostack), options(nostack));
+   |                                   ^^^^^^^ help: remove this option
+
+warning: the `nostack` option was already provided
+  --> $DIR/duplicate-options.rs:14:53
+   |
+LL |         asm!("", options(nostack, nostack), options(nostack), options(nostack));
+   |                                                     ^^^^^^^ help: remove this option
+
+warning: the `nostack` option was already provided
+  --> $DIR/duplicate-options.rs:14:71
+   |
+LL |         asm!("", options(nostack, nostack), options(nostack), options(nostack));
+   |                                                                       ^^^^^^^ help: remove this option
+
+warning: 6 warnings emitted
+