Revert shadowing change and remove no_effect allows

clippy_lints/src/no_effect.rs

@@ -14,7 +14,7 @@ declare_clippy_lint! {
     /// Checks for statements which have no effect.
     ///
     /// ### Why is this bad?
-    /// Similar to dead code, these statements are actually
+    /// Unlike dead code, these statements are actually
     /// executed. However, as they have no effect, all they do is make the code less
     /// readable.
     ///
@@ -32,7 +32,7 @@ declare_clippy_lint! {
     /// Checks for binding to underscore prefixed variable without side-effects.
     ///
     /// ### Why is this bad?
-    /// Similar to dead code, these bindings are actually
+    /// Unlike dead code, these bindings are actually
     /// executed. However, as they have no effect and shouldn't be used further on, all they
     /// do is make the code less readable.
     ///
@@ -80,7 +80,7 @@ impl<'tcx> LateLintPass<'tcx> for NoEffect {
 
 fn check_no_effect(cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) -> bool {
     if let StmtKind::Semi(expr) = stmt.kind {
-        if has_no_effect(cx, expr) && !is_lint_allowed(cx, NO_EFFECT, expr.hir_id) {
+        if has_no_effect(cx, expr) {
             span_lint_hir(cx, NO_EFFECT, expr.hir_id, stmt.span, "statement with no effect");
             return true;
         }

tests/ui-internal/if_chain_style.stderr

@@ -32,14 +32,6 @@ error: `let` expression should be inside `then { .. }`
 LL |         let x = "";
    |         ^^^^^^^^^^^
 
-error: unnecessary operation
-  --> $DIR/if_chain_style.rs:26:13
-   |
-LL |             ();
-   |             ^^^ help: statement can be reduced to
-   |
-   = note: `-D clippy::unnecessary-operation` implied by `-D warnings`
-
 error: this `if` can be part of the outer `if_chain!`
   --> $DIR/if_chain_style.rs:35:13
    |
@@ -89,23 +81,5 @@ LL | /             let x = "";
 LL | |             let x = "";
    | |_______________________^
 
-error: unnecessary operation
-  --> $DIR/if_chain_style.rs:57:9
-   |
-LL |         ();
-   |         ^^^ help: statement can be reduced to
-
-error: unnecessary operation
-  --> $DIR/if_chain_style.rs:61:20
-   |
-LL |             then { (); }
-   |                    ^^^ help: statement can be reduced to
-
-error: unnecessary operation
-  --> $DIR/if_chain_style.rs:68:16
-   |
-LL |         then { (); }
-   |                ^^^ help: statement can be reduced to
-
-error: aborting due to 11 previous errors
+error: aborting due to 7 previous errors
 

tests/ui/async_yields_async.fixed

@@ -2,7 +2,6 @@
 // edition:2018
 
 #![feature(async_closure)]
-#![allow(clippy::no_effect)]
 #![warn(clippy::async_yields_async)]
 
 use core::future::Future;

tests/ui/async_yields_async.rs

@@ -2,7 +2,6 @@
 // edition:2018
 
 #![feature(async_closure)]
-#![allow(clippy::no_effect)]
 #![warn(clippy::async_yields_async)]
 
 use core::future::Future;

tests/ui/async_yields_async.stderr

@@ -1,5 +1,5 @@
 error: an async construct yields a type which is itself awaitable
-  --> $DIR/async_yields_async.rs:41:9
+  --> $DIR/async_yields_async.rs:40:9
    |
 LL |        let _h = async {
    |   ____________________-
@@ -20,7 +20,7 @@ LL +         }.await
    |
 
 error: an async construct yields a type which is itself awaitable
-  --> $DIR/async_yields_async.rs:46:9
+  --> $DIR/async_yields_async.rs:45:9
    |
 LL |       let _i = async {
    |  ____________________-
@@ -33,7 +33,7 @@ LL | |     };
    | |_____- outer async construct
 
 error: an async construct yields a type which is itself awaitable
-  --> $DIR/async_yields_async.rs:52:9
+  --> $DIR/async_yields_async.rs:51:9
    |
 LL |        let _j = async || {
    |   _______________________-
@@ -53,7 +53,7 @@ LL +         }.await
    |
 
 error: an async construct yields a type which is itself awaitable
-  --> $DIR/async_yields_async.rs:57:9
+  --> $DIR/async_yields_async.rs:56:9
    |
 LL |       let _k = async || {
    |  _______________________-
@@ -66,7 +66,7 @@ LL | |     };
    | |_____- outer async construct
 
 error: an async construct yields a type which is itself awaitable
-  --> $DIR/async_yields_async.rs:59:23
+  --> $DIR/async_yields_async.rs:58:23
    |
 LL |     let _l = async || CustomFutureType;
    |                       ^^^^^^^^^^^^^^^^
@@ -76,7 +76,7 @@ LL |     let _l = async || CustomFutureType;
    |                       help: consider awaiting this value: `CustomFutureType.await`
 
 error: an async construct yields a type which is itself awaitable
-  --> $DIR/async_yields_async.rs:65:9
+  --> $DIR/async_yields_async.rs:64:9
    |
 LL |       let _m = async || {
    |  _______________________-

tests/ui/author/blocks.rs

@@ -1,4 +1,4 @@
-#![allow(redundant_semicolons, clippy::no_effect, clippy::unnecessary_operation)]
+#![allow(redundant_semicolons, clippy::no_effect)]
 
 #[rustfmt::skip]
 fn main() {

tests/ui/auxiliary/proc_macro_derive.rs

@@ -4,7 +4,7 @@
 #![crate_type = "proc-macro"]
 #![feature(repr128, proc_macro_quote)]
 #![allow(incomplete_features)]
-#![allow(clippy::field_reassign_with_default, clippy::no_effect)]
+#![allow(clippy::field_reassign_with_default)]
 #![allow(clippy::eq_op)]
 
 extern crate proc_macro;

tests/ui/crashes/ice-7340.rs

@@ -1,4 +1,4 @@
-#![allow(clippy::no_effect, clippy::unnecessary_operation)]
+#![allow(clippy::no_effect)]
 
 fn main() {
     const CONSTANT: usize = 8;

tests/ui/empty_line_after_outer_attribute.rs

@@ -1,6 +1,6 @@
 // aux-build:proc_macro_attr.rs
 #![warn(clippy::empty_line_after_outer_attr)]
-#![allow(clippy::assertions_on_constants, clippy::no_effect)]
+#![allow(clippy::assertions_on_constants)]
 #![feature(custom_inner_attributes)]
 #![rustfmt::skip]
 

tests/ui/erasing_op.stderr

@@ -1,11 +1,3 @@
-error: unnecessary operation
-  --> $DIR/erasing_op.rs:6:5
-   |
-LL |     x * 0;
-   |     ^^^^^^ help: statement can be reduced to: `x;0;`
-   |
-   = note: `-D clippy::unnecessary-operation` implied by `-D warnings`
-
 error: this operation will always return zero. This is likely not the intended outcome
   --> $DIR/erasing_op.rs:6:5
    |
@@ -14,29 +6,17 @@ LL |     x * 0;
    |
    = note: `-D clippy::erasing-op` implied by `-D warnings`
 
-error: unnecessary operation
-  --> $DIR/erasing_op.rs:7:5
-   |
-LL |     0 & x;
-   |     ^^^^^^ help: statement can be reduced to: `0;x;`
-
 error: this operation will always return zero. This is likely not the intended outcome
   --> $DIR/erasing_op.rs:7:5
    |
 LL |     0 & x;
    |     ^^^^^
 
-error: unnecessary operation
-  --> $DIR/erasing_op.rs:8:5
-   |
-LL |     0 / x;
-   |     ^^^^^^ help: statement can be reduced to: `0;x;`
-
 error: this operation will always return zero. This is likely not the intended outcome
   --> $DIR/erasing_op.rs:8:5
    |
 LL |     0 / x;
    |     ^^^^^
 
-error: aborting due to 6 previous errors
+error: aborting due to 3 previous errors
 

tests/ui/eta.fixed

@@ -29,7 +29,7 @@ macro_rules! closure_mac {
 
 fn main() {
     let a = Some(1u8).map(foo);
-    let c = Some(1u8).map(|a| {1;2; foo}(a));
+    let c = Some(1u8).map(|a| {1+2; foo}(a));
     true.then(|| mac!()); // don't lint function in macro expansion
     Some(1).map(closure_mac!()); // don't lint closure in macro expansion
     let _: Option<Vec<u8>> = true.then(std::vec::Vec::new); // special case vec!

tests/ui/eta.stderr

@@ -6,14 +6,6 @@ LL |     let a = Some(1u8).map(|a| foo(a));
    |
    = note: `-D clippy::redundant-closure` implied by `-D warnings`
 
-error: unnecessary operation
-  --> $DIR/eta.rs:32:32
-   |
-LL |     let c = Some(1u8).map(|a| {1+2; foo}(a));
-   |                                ^^^^ help: statement can be reduced to: `1;2;`
-   |
-   = note: `-D clippy::unnecessary-operation` implied by `-D warnings`
-
 error: redundant closure
   --> $DIR/eta.rs:35:40
    |
@@ -138,5 +130,5 @@ error: redundant closure
 LL |     map_str_to_path(|s| s.as_ref());
    |                     ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `std::convert::AsRef::as_ref`
 
-error: aborting due to 22 previous errors
+error: aborting due to 21 previous errors
 

tests/ui/for_loop_fixable.fixed

@@ -1,6 +1,5 @@
 // run-rustfix
 
-#![allow(clippy::no_effect)]
 #![allow(dead_code, unused)]
 
 use std::collections::*;

tests/ui/for_loop_fixable.rs

@@ -1,6 +1,5 @@
 // run-rustfix
 
-#![allow(clippy::no_effect)]
 #![allow(dead_code, unused)]
 
 use std::collections::*;

tests/ui/for_loop_fixable.stderr

@@ -1,93 +1,93 @@
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:39:15
+  --> $DIR/for_loop_fixable.rs:38:15
    |
 LL |     for _v in vec.iter() {}
    |               ^^^^^^^^^^ help: to write this more concisely, try: `&vec`
    |
    = note: `-D clippy::explicit-iter-loop` implied by `-D warnings`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:41:15
+  --> $DIR/for_loop_fixable.rs:40:15
    |
 LL |     for _v in vec.iter_mut() {}
    |               ^^^^^^^^^^^^^^ help: to write this more concisely, try: `&mut vec`
 
 error: it is more concise to loop over containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:44:15
+  --> $DIR/for_loop_fixable.rs:43:15
    |
 LL |     for _v in out_vec.into_iter() {}
    |               ^^^^^^^^^^^^^^^^^^^ help: to write this more concisely, try: `out_vec`
    |
    = note: `-D clippy::explicit-into-iter-loop` implied by `-D warnings`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:49:15
+  --> $DIR/for_loop_fixable.rs:48:15
    |
 LL |     for _v in [1, 2, 3].iter() {}
    |               ^^^^^^^^^^^^^^^^ help: to write this more concisely, try: `&[1, 2, 3]`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:53:15
+  --> $DIR/for_loop_fixable.rs:52:15
    |
 LL |     for _v in [0; 32].iter() {}
    |               ^^^^^^^^^^^^^^ help: to write this more concisely, try: `&[0; 32]`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:58:15
+  --> $DIR/for_loop_fixable.rs:57:15
    |
 LL |     for _v in ll.iter() {}
    |               ^^^^^^^^^ help: to write this more concisely, try: `&ll`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:61:15
+  --> $DIR/for_loop_fixable.rs:60:15
    |
 LL |     for _v in vd.iter() {}
    |               ^^^^^^^^^ help: to write this more concisely, try: `&vd`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:64:15
+  --> $DIR/for_loop_fixable.rs:63:15
    |
 LL |     for _v in bh.iter() {}
    |               ^^^^^^^^^ help: to write this more concisely, try: `&bh`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:67:15
+  --> $DIR/for_loop_fixable.rs:66:15
    |
 LL |     for _v in hm.iter() {}
    |               ^^^^^^^^^ help: to write this more concisely, try: `&hm`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:70:15
+  --> $DIR/for_loop_fixable.rs:69:15
    |
 LL |     for _v in bt.iter() {}
    |               ^^^^^^^^^ help: to write this more concisely, try: `&bt`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:73:15
+  --> $DIR/for_loop_fixable.rs:72:15
    |
 LL |     for _v in hs.iter() {}
    |               ^^^^^^^^^ help: to write this more concisely, try: `&hs`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:76:15
+  --> $DIR/for_loop_fixable.rs:75:15
    |
 LL |     for _v in bs.iter() {}
    |               ^^^^^^^^^ help: to write this more concisely, try: `&bs`
 
 error: it is more concise to loop over containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:251:18
+  --> $DIR/for_loop_fixable.rs:250:18
    |
 LL |         for i in iterator.into_iter() {
    |                  ^^^^^^^^^^^^^^^^^^^^ help: to write this more concisely, try: `iterator`
 
 error: it is more concise to loop over references to containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:271:18
+  --> $DIR/for_loop_fixable.rs:270:18
    |
 LL |         for _ in t.into_iter() {}
    |                  ^^^^^^^^^^^^^ help: to write this more concisely, try: `&t`
 
 error: it is more concise to loop over containers instead of using explicit iteration methods
-  --> $DIR/for_loop_fixable.rs:273:18
+  --> $DIR/for_loop_fixable.rs:272:18
    |
 LL |         for _ in r.into_iter() {}
    |                  ^^^^^^^^^^^^^ help: to write this more concisely, try: `r`