in which the liveness lint tests find a new home

In this commit, liveness-dead and liveness-unused are made into UI tests
(cf. #44844) rather than compile-fail tests, because then if some future
commit were to, say, change some of the spans in these lints, that
commit's diff would clearly show exactly what changed.

If. Hypothetically.

Author: zackmdavis

src/test/compile-fail/liveness-dead.rs renamed to src/test/ui/lint/liveness-dead.rs

@@ -8,33 +8,35 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// must-compile-successfully
+
 #![allow(dead_code)]
-#![deny(unused_assignments)]
+#![warn(unused_assignments)]
 
 fn f1(x: &mut isize) {
     *x = 1; // no error
 }
 
 fn f2() {
-    let mut x: isize = 3; //~ ERROR: value assigned to `x` is never read
+    let mut x: isize = 3; //~ WARN: value assigned to `x` is never read
     x = 4;
     x.clone();
 }
 
 fn f3() {
     let mut x: isize = 3;
     x.clone();
-    x = 4; //~ ERROR: value assigned to `x` is never read
+    x = 4; //~ WARN: value assigned to `x` is never read
 }
 
-fn f4(mut x: i32) { //~ ERROR: value passed to `x` is never read
+fn f4(mut x: i32) { //~ WARN: value passed to `x` is never read
     x = 4;
     x.clone();
 }
 
 fn f5(mut x: i32) {
     x.clone();
-    x = 4; //~ ERROR: value assigned to `x` is never read
+    x = 4; //~ WARN: value assigned to `x` is never read
 }
 
 fn main() {}

src/test/ui/lint/liveness-dead.stderr

@@ -0,0 +1,30 @@
+warning: value assigned to `x` is never read
+  --> $DIR/liveness-dead.rs:21:9
+   |
+LL |     let mut x: isize = 3; //~ WARN: value assigned to `x` is never read
+   |         ^^^^^
+   |
+note: lint level defined here
+  --> $DIR/liveness-dead.rs:14:9
+   |
+LL | #![warn(unused_assignments)]
+   |         ^^^^^^^^^^^^^^^^^^
+
+warning: value assigned to `x` is never read
+  --> $DIR/liveness-dead.rs:29:5
+   |
+LL |     x = 4; //~ WARN: value assigned to `x` is never read
+   |     ^
+
+warning: value passed to `x` is never read
+  --> $DIR/liveness-dead.rs:32:7
+   |
+LL | fn f4(mut x: i32) { //~ WARN: value passed to `x` is never read
+   |       ^^^^^
+
+warning: value assigned to `x` is never read
+  --> $DIR/liveness-dead.rs:39:5
+   |
+LL |     x = 4; //~ WARN: value assigned to `x` is never read
+   |     ^
+

src/test/compile-fail/liveness-unused.rs renamed to src/test/ui/lint/liveness-unused.rs

@@ -8,44 +8,44 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![warn(unused)]
-#![deny(unused_variables)]
-#![deny(unused_assignments)]
+// must-compile-successfully
+
+#![warn(unused_variables, unused_assignments, unreachable_code)]
 #![allow(dead_code, non_camel_case_types, trivial_numeric_casts)]
 
 use std::ops::AddAssign;
 
 fn f1(x: isize) {
-    //~^ ERROR unused variable: `x`
+    //~^ WARN unused variable: `x`
 }
 
 fn f1b(x: &mut isize) {
-    //~^ ERROR unused variable: `x`
+    //~^ WARN unused variable: `x`
 }
 
 #[allow(unused_variables)]
 fn f1c(x: isize) {}
 
 fn f1d() {
     let x: isize;
-    //~^ ERROR unused variable: `x`
+    //~^ WARN unused variable: `x`
 }
 
 fn f2() {
     let x = 3;
-    //~^ ERROR unused variable: `x`
+    //~^ WARN unused variable: `x`
 }
 
 fn f3() {
     let mut x = 3;
-    //~^ ERROR variable `x` is assigned to, but never used
+    //~^ WARN variable `x` is assigned to, but never used
     x += 4;
-    //~^ ERROR value assigned to `x` is never read
+    //~^ WARN value assigned to `x` is never read
 }
 
 fn f3b() {
     let mut z = 3;
-    //~^ ERROR variable `z` is assigned to, but never used
+    //~^ WARN variable `z` is assigned to, but never used
     loop {
         z += 4;
     }
@@ -67,7 +67,7 @@ fn f3d() {
 fn f4() {
     match Some(3) {
       Some(i) => {
-        //~^ ERROR unused variable: `i`
+        //~^ WARN unused variable: `i`
       }
       None => {}
     }
@@ -87,19 +87,19 @@ fn f4b() -> isize {
 
 fn f5a() {
     for x in 1..10 { }
-    //~^ ERROR unused variable: `x`
+    //~^ WARN unused variable: `x`
 }
 
 fn f5b() {
     for (x, _) in [1, 2, 3].iter().enumerate() { }
-    //~^ ERROR unused variable: `x`
+    //~^ WARN unused variable: `x`
 }
 
 fn f5c() {
     for (_, x) in [1, 2, 3].iter().enumerate() {
-    //~^ ERROR unused variable: `x`
+    //~^ WARN unused variable: `x`
         continue;
-        drop(*x as i32); //~ WARNING unreachable statement
+        drop(*x as i32); //~ WARN unreachable statement
     }
 }
 
@@ -120,10 +120,10 @@ fn f6() {
     // ensure an error shows up for x even if lhs of an overloaded add assign
 
     let x;
-    //~^ ERROR variable `x` is assigned to, but never used
+    //~^ WARN variable `x` is assigned to, but never used
 
     *({
-        x = 0;  //~ ERROR value assigned to `x` is never read
+        x = 0;  //~ WARN value assigned to `x` is never read
         &mut v
     }) += 1;
 }

src/test/ui/lint/liveness-unused.stderr

@@ -0,0 +1,108 @@
+warning: unreachable statement
+  --> $DIR/liveness-unused.rs:102:9
+   |
+LL |         drop(*x as i32); //~ WARN unreachable statement
+   |         ^^^^^^^^^^^^^^^^
+   |
+note: lint level defined here
+  --> $DIR/liveness-unused.rs:13:47
+   |
+LL | #![warn(unused_variables, unused_assignments, unreachable_code)]
+   |                                               ^^^^^^^^^^^^^^^^
+
+warning: unused variable: `x`
+  --> $DIR/liveness-unused.rs:18:7
+   |
+LL | fn f1(x: isize) {
+   |       ^ help: consider using `_x` instead
+   |
+note: lint level defined here
+  --> $DIR/liveness-unused.rs:13:9
+   |
+LL | #![warn(unused_variables, unused_assignments, unreachable_code)]
+   |         ^^^^^^^^^^^^^^^^
+
+warning: unused variable: `x`
+  --> $DIR/liveness-unused.rs:22:8
+   |
+LL | fn f1b(x: &mut isize) {
+   |        ^ help: consider using `_x` instead
+
+warning: unused variable: `x`
+  --> $DIR/liveness-unused.rs:30:9
+   |
+LL |     let x: isize;
+   |         ^ help: consider using `_x` instead
+
+warning: unused variable: `x`
+  --> $DIR/liveness-unused.rs:35:9
+   |
+LL |     let x = 3;
+   |         ^ help: consider using `_x` instead
+
+warning: variable `x` is assigned to, but never used
+  --> $DIR/liveness-unused.rs:40:9
+   |
+LL |     let mut x = 3;
+   |         ^^^^^
+   |
+   = note: consider using `_x` instead
+
+warning: value assigned to `x` is never read
+  --> $DIR/liveness-unused.rs:42:5
+   |
+LL |     x += 4;
+   |     ^
+   |
+note: lint level defined here
+  --> $DIR/liveness-unused.rs:13:27
+   |
+LL | #![warn(unused_variables, unused_assignments, unreachable_code)]
+   |                           ^^^^^^^^^^^^^^^^^^
+
+warning: variable `z` is assigned to, but never used
+  --> $DIR/liveness-unused.rs:47:9
+   |
+LL |     let mut z = 3;
+   |         ^^^^^
+   |
+   = note: consider using `_z` instead
+
+warning: unused variable: `i`
+  --> $DIR/liveness-unused.rs:69:12
+   |
+LL |       Some(i) => {
+   |            ^ help: consider using `_i` instead
+
+warning: unused variable: `x`
+  --> $DIR/liveness-unused.rs:89:9
+   |
+LL |     for x in 1..10 { }
+   |         ^ help: consider using `_x` instead
+
+warning: unused variable: `x`
+  --> $DIR/liveness-unused.rs:94:10
+   |
+LL |     for (x, _) in [1, 2, 3].iter().enumerate() { }
+   |          ^ help: consider using `_x` instead
+
+warning: unused variable: `x`
+  --> $DIR/liveness-unused.rs:99:13
+   |
+LL |     for (_, x) in [1, 2, 3].iter().enumerate() {
+   |             ^ help: consider using `_x` instead
+
+warning: variable `x` is assigned to, but never used
+  --> $DIR/liveness-unused.rs:122:9
+   |
+LL |     let x;
+   |         ^
+   |
+   = note: consider using `_x` instead
+
+warning: value assigned to `x` is never read
+  --> $DIR/liveness-unused.rs:126:9
+   |
+LL |         x = 0;  //~ WARN value assigned to `x` is never read
+   |         ^
+