Auto merge of rust-lang#106916 - lukas-code:overlapping-substs, r=estebank

Remove overlapping parts of multipart suggestions

This PR adds a debug assertion that the parts of a single substitution cannot overlap, fixes a overlapping substitution from the testsuite, and fixes rust-lang#106870.

Note that a single suggestion can still have multiple overlapping substitutions / possible edits, we just don't suggest overlapping replacements in a single edit anymore.

I've also included a fix for an unrelated bug where rustfix for `explicit_outlives_requirements` would produce multiple trailing commas for a where clause.

Author: bors

clippy_lints/src/format_args.rs

@@ -311,6 +311,10 @@ fn check_uninlined_args(
     // in those cases, make the code suggestion hidden
     let multiline_fix = fixes.iter().any(|(span, _)| cx.sess().source_map().is_multiline(*span));
 
+    // Suggest removing each argument only once, for example in `format!("{0} {0}", arg)`.
+    fixes.sort_unstable_by_key(|(span, _)| *span);
+    fixes.dedup_by_key(|(span, _)| *span);
+
     span_lint_and_then(
         cx,
         UNINLINED_FORMAT_ARGS,