removed some feature gates for let_chains and reverted function names

Author: Kivooeo

tests/ui/mir/mir_match_guard_let_chains_drop_order.rs

@@ -6,7 +6,6 @@
 
 // See `mir_drop_order.rs` for more information
 
-#![cfg_attr(edition2021, feature(let_chains))]
 #![allow(irrefutable_let_patterns)]
 
 use std::cell::RefCell;

tests/ui/nll/match-guards-partially-borrow.rs

@@ -14,7 +14,7 @@ fn ok_mutation_in_if_guard(mut q: i32) {
     }
 }
 
-fn ok_mutation_in_(mut q: i32) {
+fn ok_mutation_in_if_let_guard(mut q: i32) {
     match q {
         // OK, mutation doesn't change which patterns g matches
         _ if let Some(()) = { q = 1; None } => (),
@@ -81,7 +81,7 @@ fn ok_indirect_mutation_in_if_guard(mut p: &bool) {
     }
 }
 
-fn ok_indirect_mutation_in_(mut p: &bool) {
+fn ok_indirect_mutation_in_if_let_guard(mut p: &bool) {
     match *p {
         // OK, mutation doesn't change which patterns s matches
         _ if let Some(()) = {
@@ -103,7 +103,7 @@ fn mutation_invalidates_pattern_in_if_guard(mut q: bool) {
     }
 }
 
-fn mutation_invalidates_pattern_in_(mut q: bool) {
+fn mutation_invalidates_pattern_in_if_let_guard(mut q: bool) {
     match q {
         // q doesn't match the pattern with the guard by the end of the guard.
         false if let Some(()) = {
@@ -126,7 +126,7 @@ fn mutation_invalidates_previous_pattern_in_if_guard(mut r: bool) {
     }
 }
 
-fn mutation_invalidates_previous_pattern_in_(mut r: bool) {
+fn mutation_invalidates_previous_pattern_in_if_let_guard(mut r: bool) {
     match r {
         // r matches a previous pattern by the end of the guard.
         true => (),
@@ -151,7 +151,7 @@ fn match_on_borrowed_early_end_if_guard(mut s: bool) {
     }
 }
 
-fn match_on_borrowed_early_end_(mut s: bool) {
+fn match_on_borrowed_early_end_if_let_guard(mut s: bool) {
     let h = &mut s;
     // OK value of s is unused before modification.
     match s {
@@ -175,7 +175,7 @@ fn bad_mutation_in_if_guard(mut t: bool) {
     }
 }
 
-fn bad_mutation_in_(mut t: bool) {
+fn bad_mutation_in_if_let_guard(mut t: bool) {
     match t {
         true => (),
         false if let Some(()) = {
@@ -249,7 +249,7 @@ fn bad_indirect_mutation_in_if_guard(mut y: &bool) {
     }
 }
 
-fn bad_indirect_mutation_in_(mut y: &bool) {
+fn bad_indirect_mutation_in_if_let_guard(mut y: &bool) {
     match *y {
         true => (),
         false if let Some(()) = {

tests/ui/rfcs/rfc-2294-if-let-guard/shadowing.rs

@@ -5,8 +5,6 @@
 //@[edition2021] edition:2021
 //@[edition2024] edition:2024
 
-#![cfg_attr(edition2021, feature(let_chains))]
-
 fn main() {
     let x: Option<Option<i32>> = Some(Some(6));
     match x {

tests/ui/rfcs/rfc-2294-if-let-guard/temporary-early-drop.rs

@@ -5,7 +5,6 @@
 //@ check-pass
 
 #![allow(irrefutable_let_patterns)]
-#![cfg_attr(edition2021, feature(let_chains))]
 
 struct Pd;