Add some more tests

Author: petrochenkov

src/test/ui/asm/asm-literal-escaping.rs

@@ -0,0 +1,12 @@
+// build-pass
+// only-x86_64
+
+#![feature(asm)]
+
+fn main() {
+    unsafe {
+        // "nop" :: "r"(x) : "eax" : "volatile"
+        let x = 10;
+        asm!("\x6Eop" :: "\x72"(x) : "\x65ax" : "\x76olatile");
+    }
+}

src/test/ui/proc-macro/span-preservation.rs

@@ -44,4 +44,14 @@ extern "C" fn baz() {
     0 //~ ERROR mismatched types
 }
 
+#[recollect_attr]
+extern "Rust" fn rust_abi() {
+    0 //~ ERROR mismatched types
+}
+
+#[recollect_attr]
+extern "\x43" fn c_abi_escaped() {
+    0 //~ ERROR mismatched types
+}
+
 fn main() {}

src/test/ui/proc-macro/span-preservation.stderr

@@ -52,7 +52,29 @@ LL |     0
    = note: expected type `()`
               found type `{integer}`
 
-error: aborting due to 6 previous errors
+error[E0308]: mismatched types
+  --> $DIR/span-preservation.rs:49:5
+   |
+LL | extern "Rust" fn rust_abi() {
+   |                             - possibly return type missing here?
+LL |     0
+   |     ^ expected (), found integer
+   |
+   = note: expected type `()`
+              found type `{integer}`
+
+error[E0308]: mismatched types
+  --> $DIR/span-preservation.rs:54:5
+   |
+LL | extern "\x43" fn c_abi_escaped() {
+   |                                  - possibly return type missing here?
+LL |     0
+   |     ^ expected (), found integer
+   |
+   = note: expected type `()`
+              found type `{integer}`
+
+error: aborting due to 8 previous errors
 
 Some errors have detailed explanations: E0308, E0560.
 For more information about an error, try `rustc --explain E0308`.