fix clippy::needless_return: remove unneeded return statements

library/test/src/helpers/concurrency.rs

@@ -4,7 +4,7 @@ use std::env;
 
 #[allow(deprecated)]
 pub fn get_concurrency() -> usize {
-    return match env::var("RUST_TEST_THREADS") {
+    match env::var("RUST_TEST_THREADS") {
         Ok(s) => {
             let opt_n: Option<usize> = s.parse().ok();
             match opt_n {
@@ -13,7 +13,7 @@ pub fn get_concurrency() -> usize {
             }
         }
         Err(..) => num_cpus(),
-    };
+    }
 }
 
 cfg_if::cfg_if! {

src/librustc_codegen_llvm/debuginfo/metadata.rs

@@ -960,7 +960,7 @@ fn pointer_type_metadata(
 fn param_type_metadata(cx: &CodegenCx<'ll, 'tcx>, t: Ty<'tcx>) -> &'ll DIType {
     debug!("param_type_metadata: {:?}", t);
     let name = format!("{:?}", t);
-    return unsafe {
+    unsafe {
         llvm::LLVMRustDIBuilderCreateBasicType(
             DIB(cx),
             name.as_ptr().cast(),
@@ -968,7 +968,7 @@ fn param_type_metadata(cx: &CodegenCx<'ll, 'tcx>, t: Ty<'tcx>) -> &'ll DIType {
             Size::ZERO.bits(),
             DW_ATE_unsigned,
         )
-    };
+    }
 }
 
 pub fn compile_unit_metadata(

src/librustc_infer/infer/region_constraints/leak_check.rs

@@ -288,9 +288,9 @@ impl<'me, 'tcx> LeakCheck<'me, 'tcx> {
     ) -> TypeError<'tcx> {
         debug!("error: placeholder={:?}, other_region={:?}", placeholder, other_region);
         if self.overly_polymorphic {
-            return TypeError::RegionsOverlyPolymorphic(placeholder.name, other_region);
+            TypeError::RegionsOverlyPolymorphic(placeholder.name, other_region)
         } else {
-            return TypeError::RegionsInsufficientlyPolymorphic(placeholder.name, other_region);
+            TypeError::RegionsInsufficientlyPolymorphic(placeholder.name, other_region)
         }
     }
 }

src/librustc_lint/types.rs

@@ -1074,7 +1074,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
             }
             // If `ty` is a `repr(transparent)` newtype, and the non-zero-sized type is a generic
             // argument, which after substitution, is `()`, then this branch can be hit.
-            FfiResult::FfiUnsafe { ty, .. } if is_return_type && ty.is_unit() => return,
+            FfiResult::FfiUnsafe { ty, .. } if is_return_type && ty.is_unit() => {}
             FfiResult::FfiUnsafe { ty, reason, help } => {
                 self.emit_ffi_unsafe_type_lint(ty, sp, &reason, help.as_deref());
             }

src/librustc_mir/borrow_check/diagnostics/mod.rs

@@ -868,7 +868,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 }
             }
         }
-        return normal_ret;
+        normal_ret
     }
 
     /// Finds the span of arguments of a closure (within `maybe_closure_span`)

src/librustc_mir/transform/simplify_try.rs

@@ -361,7 +361,7 @@ fn optimization_applies<'tcx>(
     }
 
     trace!("SUCCESS: optimization applies!");
-    return true;
+    true
 }
 
 impl<'tcx> MirPass<'tcx> for SimplifyArmIdentity {

src/librustc_span/hygiene.rs

@@ -1030,7 +1030,7 @@ pub fn decode_expn_id<
         drop(expns);
         expn_id
     });
-    return Ok(expn_id);
+    Ok(expn_id)
 }
 
 // Decodes `SyntaxContext`, using the provided `HygieneDecodeContext`
@@ -1103,7 +1103,7 @@ pub fn decode_syntax_context<
         assert_eq!(dummy.dollar_crate_name, kw::Invalid);
     });
 
-    return Ok(new_ctxt);
+    Ok(new_ctxt)
 }
 
 pub fn num_syntax_ctxts() -> usize {

src/librustc_traits/chalk/db.rs

@@ -174,7 +174,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
                 phantom_data: adt_def.is_phantom_data(),
             },
         });
-        return struct_datum;
+        struct_datum
     }
 
     fn fn_def_datum(

src/librustc_typeck/mem_categorization.rs

@@ -583,7 +583,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
                 self.tcx()
                     .sess
                     .delay_span_bug(span, "struct or tuple struct pattern not applied to an ADT");
-                return Err(());
+                Err(())
             }
         }
     }
@@ -596,7 +596,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
             ty::Tuple(substs) => Ok(substs.len()),
             _ => {
                 self.tcx().sess.delay_span_bug(span, "tuple pattern not applied to a tuple");
-                return Err(());
+                Err(())
             }
         }
     }