add warning for missing docs

Author: Dylan-DPC

src/test/ui/lint/lints-in-foreign-macros.rs

@@ -12,7 +12,7 @@
 // compile-pass
 
 #![warn(unused_imports)]
-#![warn(missing_docs)] //~ WARN: missing documentation for crate [missing_docs]
+#![warn(missing_docs)]
 
 #[macro_use]
 extern crate lints_in_foreign_macros;
@@ -25,5 +25,6 @@ mod a { foo!(); }
 mod b { bar!(); }
 mod c { baz!(use std::string::ToString;); } //~ WARN: unused import
 mod d { baz2!(use std::string::ToString;); } //~ WARN: unused import
+mod e { baz!(pub fn undocumented() {}); }//~ WARN: missing documentation for a function
 
 fn main() {}

src/test/ui/lint/lints-in-foreign-macros.stderr

@@ -29,17 +29,17 @@ warning: missing documentation for crate
   --> $DIR/lints-in-foreign-macros.rs:14:1
    |
 LL | / #![warn(unused_imports)]
-LL | | #![warn(missing_docs)] //~ WARN: missing documentation for crate [missing_docs]
+LL | | #![warn(missing_docs)]
 LL | |
 LL | | #[macro_use]
 ...  |
 LL | |
-LL | | fn main() {}
+LL | | fn main() {} //~ WARN: missing documentation for crate [missing_docs]
    | |____________^
    |
 note: lint level defined here
   --> $DIR/lints-in-foreign-macros.rs:15:9
    |
-LL | #![warn(missing_docs)] //~ WARN: missing documentation for crate [missing_docs]
+LL | #![warn(missing_docs)]
    |         ^^^^^^^^^^^^