fix clippy test

Author: RalfJung

src/tools/clippy/tests/ui/new_without_default.rs

@@ -1,4 +1,3 @@
-#![feature(const_fn)]
 #![allow(dead_code, clippy::missing_safety_doc)]
 #![warn(clippy::new_without_default)]
 

src/tools/clippy/tests/ui/new_without_default.stderr

@@ -1,5 +1,5 @@
 error: you should consider adding a `Default` implementation for `Foo`
-  --> $DIR/new_without_default.rs:8:5
+  --> $DIR/new_without_default.rs:7:5
    |
 LL | /     pub fn new() -> Foo {
 LL | |         Foo
@@ -17,7 +17,7 @@ LL | }
    |
 
 error: you should consider adding a `Default` implementation for `Bar`
-  --> $DIR/new_without_default.rs:16:5
+  --> $DIR/new_without_default.rs:15:5
    |
 LL | /     pub fn new() -> Self {
 LL | |         Bar
@@ -34,7 +34,7 @@ LL | }
    |
 
 error: you should consider adding a `Default` implementation for `LtKo<'c>`
-  --> $DIR/new_without_default.rs:80:5
+  --> $DIR/new_without_default.rs:79:5
    |
 LL | /     pub fn new() -> LtKo<'c> {
 LL | |         unimplemented!()
@@ -51,7 +51,7 @@ LL | }
    |
 
 error: you should consider adding a `Default` implementation for `NewNotEqualToDerive`
-  --> $DIR/new_without_default.rs:157:5
+  --> $DIR/new_without_default.rs:156:5
    |
 LL | /     pub fn new() -> Self {
 LL | |         NewNotEqualToDerive { foo: 1 }
@@ -68,7 +68,7 @@ LL | }
    |
 
 error: you should consider adding a `Default` implementation for `FooGenerics<T>`
-  --> $DIR/new_without_default.rs:165:5
+  --> $DIR/new_without_default.rs:164:5
    |
 LL | /     pub fn new() -> Self {
 LL | |         Self(Default::default())
@@ -85,7 +85,7 @@ LL | }
    |
 
 error: you should consider adding a `Default` implementation for `BarGenerics<T>`
-  --> $DIR/new_without_default.rs:172:5
+  --> $DIR/new_without_default.rs:171:5
    |
 LL | /     pub fn new() -> Self {
 LL | |         Self(Default::default())