fix clippy::{clone_on_copy, useless_conversion}

Author: matthiaskrgr

Diff for: compiler/rustc_borrowck/src/lib.rs

@@ -528,7 +528,7 @@ impl<'cx, 'tcx> BorrowckInferCtxt<'cx, 'tcx> {
     where
         F: Fn() -> RegionCtxt,
     {
-        let next_region = self.infcx.next_nll_region_var(origin.clone());
+        let next_region = self.infcx.next_nll_region_var(origin);
         let vid = next_region.as_var();
 
         if cfg!(debug_assertions) && !self.inside_canonicalization_ctxt() {

Diff for: compiler/rustc_hir_analysis/src/collect/predicates_of.rs

@@ -645,9 +645,8 @@ pub(super) fn implied_predicates_with_filter(
     };
 
     // Combine the two lists to form the complete set of superbounds:
-    let implied_bounds = &*tcx
-        .arena
-        .alloc_from_iter(superbounds.predicates().into_iter().chain(where_bounds_that_match));
+    let implied_bounds =
+        &*tcx.arena.alloc_from_iter(superbounds.predicates().chain(where_bounds_that_match));
     debug!(?implied_bounds);
 
     // Now require that immediate supertraits are converted,

Diff for: compiler/rustc_query_impl/src/profiling_support.rs

@@ -231,7 +231,7 @@ pub(crate) fn alloc_self_profile_query_strings_for_query_cache<'tcx, C>(
             // locked while doing so. Instead we copy out the
             // `(query_key, dep_node_index)` pairs and release the lock again.
             let mut query_keys_and_indices = Vec::new();
-            query_cache.iter(&mut |k, _, i| query_keys_and_indices.push((k.clone(), i)));
+            query_cache.iter(&mut |k, _, i| query_keys_and_indices.push((*k, i)));
 
             // Now actually allocate the strings. If allocating the strings
             // generates new entries in the query cache, we'll miss them but