Auto merge of #46857 - estebank:use-loop-sp, r=nikomatsakis

Point at `while true` span instead of entire block

src/librustc_lint/builtin.rs

@@ -102,11 +102,9 @@ fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
                 if let ast::LitKind::Bool(true) = lit.node {
                     if lit.span.ctxt() == SyntaxContext::empty() {
                         let msg = "denote infinite loops with `loop { ... }`";
-                        let mut err = cx.struct_span_lint(WHILE_TRUE, e.span, msg);
                         let condition_span = cx.tcx.sess.codemap().def_span(e.span);
-                        err.span_suggestion_short(condition_span,
-                                                  "use `loop`",
-                                                  "loop".to_owned());
+                        let mut err = cx.struct_span_lint(WHILE_TRUE, condition_span, msg);
+                        err.span_suggestion_short(condition_span, "use `loop`", "loop".to_owned());
                         err.emit();
                     }
                 }

src/test/ui/codemap_tests/unicode_3.stderr

@@ -2,9 +2,7 @@ warning: denote infinite loops with `loop { ... }`
   --> $DIR/unicode_3.rs:14:45
    |
 14 |     let s = "ZͨA͑ͦ͒͋ͤ͑̚L̄͑͋Ĝͨͥ̿͒̽̈́Oͥ͛ͭ!̏"; while true { break; }
-   |                       ----------^^^^^^^^^^^
-   |                       |
-   |                       help: use `loop`
+   |                       ^^^^^^^^^^ help: use `loop`
    |
    = note: #[warn(while_true)] on by default
 

src/test/ui/issue-1962.stderr

@@ -1,15 +1,8 @@
 error: denote infinite loops with `loop { ... }`
   --> $DIR/issue-1962.rs:14:3
    |
-14 |     while true  { //~ ERROR denote infinite loops with `loop
-   |     ^---------
-   |     |
-   |  ___help: use `loop`
-   | |
-15 | |     i += 1;
-16 | |     if i == 5 { break; }
-17 | |   }
-   | |___^
+14 |   while true  { //~ ERROR denote infinite loops with `loop
+   |   ^^^^^^^^^^ help: use `loop`
    |
    = note: requested on the command line with `-D while-true`
 

src/test/ui/lint/suggestions.stderr

@@ -75,18 +75,8 @@ warning: function is marked #[no_mangle], but not exported
 warning: denote infinite loops with `loop { ... }`
   --> $DIR/suggestions.rs:34:5
    |
-34 |       while true { // should suggest `loop`
-   |       ^---------
-   |       |
-   |  _____help: use `loop`
-   | |
-35 | |     //~^ WARN denote infinite loops
-36 | |         let mut a = (1); // should suggest no `mut`, no parens
-37 | |         //~^ WARN does not need to be mutable
-...  |
-44 | |         println!("{}", a);
-45 | |     }
-   | |_____^
+34 |     while true { // should suggest `loop`
+   |     ^^^^^^^^^^ help: use `loop`
    |
    = note: #[warn(while_true)] on by default