Add localhost.txt and more test cases for external included expression

Author: relaxcn

tests/ui/ip_constant.fixed

@@ -102,17 +102,6 @@ fn macro_test() {
     // no lint
 }
 
-include!("ip_constant_included.rs");
-
-fn external_constant_test() {
-    use std::net::{Ipv4Addr, Ipv6Addr};
-
-    let _ = Ipv4Addr::LOCALHOST;
-    //~^ ip_constant
-
-    let _ = Ipv6Addr::LOCALHOST;
-}
-
 fn main() {
     // UI Test
 }

tests/ui/ip_constant.rs

@@ -122,27 +122,6 @@ fn macro_test() {
     // no lint
 }
 
-include!("ip_constant_included.rs");
-
-fn external_constant_test() {
-    use std::net::{Ipv4Addr, Ipv6Addr};
-
-    let _ = Ipv4Addr::new(EXTERNAL_CONST_U8_127, 0, 0, 1);
-    //~^ ip_constant
-
-    let _ = Ipv6Addr::new(
-        //~^ ip_constant
-        EXTERNAL_CONST_U16_0,
-        0,
-        0,
-        0,
-        0,
-        0,
-        0,
-        1,
-    );
-}
-
 fn main() {
     // UI Test
 }

tests/ui/ip_constant.stderr

@@ -165,24 +165,5 @@ error: use `Ipv6Addr::LOCALHOST` instead
 LL |     let _ = Ipv6Addr::new(0 + 0, 0, 0, 0, 0, { 2 - 1 - CONST_U16_1 }, 0, 1);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Ipv6Addr::LOCALHOST`
 
-error: use `Ipv4Addr::LOCALHOST` instead
-  --> tests/ui/ip_constant.rs:130:13
-   |
-LL |     let _ = Ipv4Addr::new(EXTERNAL_CONST_U8_127, 0, 0, 1);
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Ipv4Addr::LOCALHOST`
-
-error: use `Ipv6Addr::LOCALHOST` instead
-  --> tests/ui/ip_constant.rs:133:13
-   |
-LL |       let _ = Ipv6Addr::new(
-   |  _____________^
-LL | |
-LL | |         EXTERNAL_CONST_U16_0,
-LL | |         0,
-...  |
-LL | |         1,
-LL | |     );
-   | |_____^ help: try: `Ipv6Addr::LOCALHOST`
-
-error: aborting due to 27 previous errors
+error: aborting due to 25 previous errors
 

tests/ui/ip_constant_from_external.rs

@@ -0,0 +1,12 @@
+//@error-in-other-file: use `std::net::Ipv4Addr::LOCALHOST` instead
+//@no-rustfix
+#![warn(clippy::ip_constant)]
+
+fn external_constant_test() {
+    let _ = include!("localhost.txt");
+    // lint in external file `localhost.txt`
+}
+
+fn main() {
+    external_constant_test();
+}

tests/ui/ip_constant_from_external.stderr

@@ -0,0 +1,11 @@
+error: use `std::net::Ipv4Addr::LOCALHOST` instead
+  --> tests/ui/localhost.txt:1:1
+   |
+LL | std::net::Ipv4Addr::new(127, 0, 0, 1)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::net::Ipv4Addr::LOCALHOST`
+   |
+   = note: `-D clippy::ip-constant` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::ip_constant)]`
+
+error: aborting due to 1 previous error
+

tests/ui/ip_constant_included.rs

@@ -0,0 +1 @@
+std::net::Ipv4Addr::new(127, 0, 0, 1)