compiler: clippy::complexity fixes

useless_format
map_flatten
useless_conversion
needless_bool
filter_next
clone_on_copy
needless_option_as_deref

3 files changed, 3 insertions, 3 deletions

diff --git a/compiler/rustc_middle/src/middle/stability.rs b/compiler/rustc_middle/src/middle/stability.rs
index 6d531d3e7d6..d080405927b 100644
--- a/compiler/rustc_middle/src/middle/stability.rs
+++ b/compiler/rustc_middle/src/middle/stability.rs
@@ -198,7 +198,7 @@ fn deprecation_message(
     } else {
         let since = since.as_ref().map(Symbol::as_str);
 
-        if since.as_deref() == Some("TBD") {
+        if since == Some("TBD") {
             format!("use of {} `{}` that will be deprecated in a future Rust version", kind, path)
         } else {
             format!(
diff --git a/compiler/rustc_middle/src/ty/relate.rs b/compiler/rustc_middle/src/ty/relate.rs
index bb040acd270..e5d44a72421 100644
--- a/compiler/rustc_middle/src/ty/relate.rs
+++ b/compiler/rustc_middle/src/ty/relate.rs
@@ -855,7 +855,7 @@ impl<'tcx> Relate<'tcx> for ty::ProjectionPredicate<'tcx> {
     ) -> RelateResult<'tcx, ty::ProjectionPredicate<'tcx>> {
         Ok(ty::ProjectionPredicate {
             projection_ty: relation.relate(a.projection_ty, b.projection_ty)?,
-            term: relation.relate(a.term, b.term)?.into(),
+            term: relation.relate(a.term, b.term)?,
         })
     }
 }
diff --git a/compiler/rustc_middle/src/ty/trait_def.rs b/compiler/rustc_middle/src/ty/trait_def.rs
index 9e32c0162e6..0e9ece77da7 100644
--- a/compiler/rustc_middle/src/ty/trait_def.rs
+++ b/compiler/rustc_middle/src/ty/trait_def.rs
@@ -214,7 +214,7 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn all_impls(self, def_id: DefId) -> impl Iterator<Item = DefId> + 'tcx {
         let TraitImpls { blanket_impls, non_blanket_impls } = self.trait_impls_of(def_id);
 
-        blanket_impls.iter().chain(non_blanket_impls.iter().map(|(_, v)| v).flatten()).cloned()
+        blanket_impls.iter().chain(non_blanket_impls.iter().flat_map(|(_, v)| v)).cloned()
     }
 }