test that extern lits accept raw strings annd escapes

Author: Centril

src/test/ui/parser/extern-abi-raw-strings.rs

@@ -0,0 +1,13 @@
+// check-pass
+
+// Check that the string literal in `extern lit` will accept raw strings.
+
+fn main() {}
+
+extern r#"C"# fn foo() {}
+
+extern r#"C"# {
+    fn bar();
+}
+
+type T = extern r#"C"# fn();

src/test/ui/parser/extern-abi-string-escaping.rs

@@ -0,0 +1,13 @@
+// check-pass
+
+// Check that the string literal in `extern lit` will escapes.
+
+fn main() {}
+
+extern "\x43" fn foo() {}
+
+extern "\x43" {
+    fn bar();
+}
+
+type T = extern "\x43" fn();