Change the error message for multiple unused print params

Author: perryprog

src/libsyntax_ext/format.rs

@@ -798,9 +798,13 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
             } else {
                 let mut diag = cx.ecx.struct_span_err(cx.fmtsp,
                     "multiple unused formatting arguments");
-                for (sp, msg) in errs {
-                    diag.span_note(sp, msg);
+
+                // Ignoring message, as it gets repetitive
+                // Then use MultiSpan to not clutter up errors
+                for (sp, _) in errs {
+                    diag.span_label(sp, "unused");
                 }
+
                 diag
             }
         };

src/test/ui/macros/format-foreign.stderr

@@ -2,23 +2,12 @@ error: multiple unused formatting arguments
   --> $DIR/format-foreign.rs:12:5
    |
 12 |     println!("%.*3$s %s!/n", "Hello,", "World", 4);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^--------^^-------^^-^^
+   |                              |         |        |
+   |                              |         |        unused
+   |                              |         unused
+   |                              unused
    |
-note: argument never used
-  --> $DIR/format-foreign.rs:12:30
-   |
-12 |     println!("%.*3$s %s!/n", "Hello,", "World", 4);
-   |                              ^^^^^^^^
-note: argument never used
-  --> $DIR/format-foreign.rs:12:40
-   |
-12 |     println!("%.*3$s %s!/n", "Hello,", "World", 4);
-   |                                        ^^^^^^^
-note: argument never used
-  --> $DIR/format-foreign.rs:12:49
-   |
-12 |     println!("%.*3$s %s!/n", "Hello,", "World", 4);
-   |                                                 ^
    = help: `%.*3$s` should be written as `{:.2$}`
    = help: `%s` should be written as `{}`
    = note: printf formatting not supported; see the documentation for `std::fmt`