Remove #[allow]s. Apply conversations from @Jarcho

clippy_lints/src/functions/impl_trait_in_params.rs

@@ -11,27 +11,20 @@ pub(super) fn check_fn<'tcx>(cx: &LateContext<'_>, kind: &'tcx FnKind<'_>, body:
     {
         if let FnKind::ItemFn(ident, generics, _) = kind {
             for param in generics.params {
-                if param.is_impl_trait()
-                    && !param.name.ident().as_str().contains('<')
-                    && !param.name.ident().as_str().contains('(')
-                {
+                if param.is_impl_trait() {
                     // No generics with nested generics, and no generics like FnMut(x)
                     span_lint_and_then(
                         cx,
                         IMPL_TRAIT_IN_PARAMS,
                         param.span,
-                        &format!("'{}' in the function's parameters", param.name.ident().as_str()),
+                        "'`impl Trait` used as a function parameter'",
                         |diag| {
                             let next_letter = next_valid_letter(generics);
                             if let Some(gen_span) = generics.span_for_param_suggestion() {
                                 diag.span_suggestion_with_style(
                                     gen_span,
-                                    format!(
-                                        "create a generic type here and replace that `{}` with `{}`",
-                                        param.name.ident().as_str(),
-                                        next_letter
-                                    ),
-                                    ", T: Trait",
+                                    "add a type paremeter, `{}`: `{}`",
+                                    format!(", {next_letter}: {}", &param.name.ident().as_str()[5..]),
                                     rustc_errors::Applicability::MaybeIncorrect,
                                     rustc_errors::SuggestionStyle::ShowAlways,
                                 );
@@ -46,12 +39,8 @@ pub(super) fn check_fn<'tcx>(cx: &LateContext<'_>, kind: &'tcx FnKind<'_>, body:
                                         ident.span.ctxt(),
                                         ident.span.parent(),
                                     ),
-                                    format!(
-                                        "create a generic type here and replace that '{}' with `{}`",
-                                        param.name.ident().as_str(),
-                                        next_letter
-                                    ),
-                                    "<T: Trait>",
+                                    "add a type paremeter",
+                                    format!("<{next_letter}: {}>", &param.name.ident().as_str()[5..]),
                                     rustc_errors::Applicability::MaybeIncorrect,
                                     rustc_errors::SuggestionStyle::ShowAlways,
                                 );

clippy_utils/src/ast_utils.rs

@@ -2,12 +2,7 @@
 //!
 //! - The `eq_foobar` functions test for semantic equality but ignores `NodeId`s and `Span`s.
 
-#![allow(
-    clippy::similar_names,
-    clippy::wildcard_imports,
-    clippy::enum_glob_use,
-    clippy::impl_trait_in_params
-)]
+#![allow(clippy::similar_names, clippy::wildcard_imports, clippy::enum_glob_use)]
 
 use crate::{both, over};
 use rustc_ast::ptr::P;

clippy_utils/src/check_proc_macro.rs

@@ -1,4 +1,3 @@
-#![allow(clippy::impl_trait_in_params)]
 //! This module handles checking if the span given is from a proc-macro or not.
 //!
 //! Proc-macros are capable of setting the span of every token they output to a few possible spans.

clippy_utils/src/hir_utils.rs

@@ -1,4 +1,3 @@
-#![allow(clippy::impl_trait_in_params)]
 use crate::consts::constant_simple;
 use crate::macros::macro_backtrace;
 use crate::source::snippet_opt;

clippy_utils/src/macros.rs

@@ -1,4 +1,4 @@
-#![allow(clippy::similar_names, clippy::impl_trait_in_params)] // `expr` and `expn`
+#![allow(clippy::similar_names)] // `expr` and `expn`
 
 use crate::is_path_diagnostic_item;
 use crate::source::snippet_opt;

clippy_utils/src/source.rs

@@ -1,6 +1,6 @@
 //! Utils for extracting, inspecting or transforming source code
 
-#![allow(clippy::module_name_repetitions, clippy::impl_trait_in_params)]
+#![allow(clippy::module_name_repetitions)]
 
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};

tests/ui/borrow_box.rs

@@ -1,10 +1,6 @@
 #![deny(clippy::borrowed_box)]
 #![allow(dead_code, unused_variables)]
-#![allow(
-    clippy::uninlined_format_args,
-    clippy::disallowed_names,
-    clippy::impl_trait_in_params
-)]
+#![allow(clippy::uninlined_format_args, clippy::disallowed_names)]
 
 use std::fmt::Display;
 

tests/ui/borrow_box.stderr

@@ -1,5 +1,5 @@
 error: you seem to be trying to use `&Box<T>`. Consider using just `&T`
-  --> $DIR/borrow_box.rs:24:14
+  --> $DIR/borrow_box.rs:20:14
    |
 LL |     let foo: &Box<bool>;
    |              ^^^^^^^^^^ help: try: `&bool`
@@ -11,55 +11,55 @@ LL | #![deny(clippy::borrowed_box)]
    |         ^^^^^^^^^^^^^^^^^^^^
 
 error: you seem to be trying to use `&Box<T>`. Consider using just `&T`
-  --> $DIR/borrow_box.rs:28:10
+  --> $DIR/borrow_box.rs:24:10
    |
 LL |     foo: &'a Box<bool>,
    |          ^^^^^^^^^^^^^ help: try: `&'a bool`
 
 error: you seem to be trying to use `&Box<T>`. Consider using just `&T`
-  --> $DIR/borrow_box.rs:32:17
+  --> $DIR/borrow_box.rs:28:17
    |
 LL |     fn test4(a: &Box<bool>);
    |                 ^^^^^^^^^^ help: try: `&bool`
 
 error: you seem to be trying to use `&Box<T>`. Consider using just `&T`
-  --> $DIR/borrow_box.rs:98:25
+  --> $DIR/borrow_box.rs:94:25
    |
 LL | pub fn test14(_display: &Box<dyn Display>) {}
    |                         ^^^^^^^^^^^^^^^^^ help: try: `&dyn Display`
 
 error: you seem to be trying to use `&Box<T>`. Consider using just `&T`
-  --> $DIR/borrow_box.rs:99:25
+  --> $DIR/borrow_box.rs:95:25
    |
 LL | pub fn test15(_display: &Box<dyn Display + Send>) {}
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&(dyn Display + Send)`
 
 error: you seem to be trying to use `&Box<T>`. Consider using just `&T`
-  --> $DIR/borrow_box.rs:100:29
+  --> $DIR/borrow_box.rs:96:29
    |
 LL | pub fn test16<'a>(_display: &'a Box<dyn Display + 'a>) {}
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&'a (dyn Display + 'a)`
 
 error: you seem to be trying to use `&Box<T>`. Consider using just `&T`
-  --> $DIR/borrow_box.rs:102:25
+  --> $DIR/borrow_box.rs:98:25
    |
 LL | pub fn test17(_display: &Box<impl Display>) {}
    |                         ^^^^^^^^^^^^^^^^^^ help: try: `&impl Display`
 
 error: you seem to be trying to use `&Box<T>`. Consider using just `&T`
-  --> $DIR/borrow_box.rs:103:25
+  --> $DIR/borrow_box.rs:99:25
    |
 LL | pub fn test18(_display: &Box<impl Display + Send>) {}
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&(impl Display + Send)`
 
 error: you seem to be trying to use `&Box<T>`. Consider using just `&T`
-  --> $DIR/borrow_box.rs:104:29
+  --> $DIR/borrow_box.rs:100:29
    |
 LL | pub fn test19<'a>(_display: &'a Box<impl Display + 'a>) {}
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&'a (impl Display + 'a)`
 
 error: you seem to be trying to use `&Box<T>`. Consider using just `&T`
-  --> $DIR/borrow_box.rs:109:25
+  --> $DIR/borrow_box.rs:105:25
    |
 LL | pub fn test20(_display: &Box<(dyn Display + Send)>) {}
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `&(dyn Display + Send)`

tests/ui/eta.fixed

@@ -7,8 +7,7 @@
     clippy::no_effect,
     clippy::option_map_unit_fn,
     clippy::redundant_closure_call,
-    clippy::uninlined_format_args,
-    clippy::impl_trait_in_params
+    clippy::uninlined_format_args
 )]
 
 use std::path::{Path, PathBuf};

tests/ui/eta.rs

@@ -7,8 +7,7 @@
     clippy::no_effect,
     clippy::option_map_unit_fn,
     clippy::redundant_closure_call,
-    clippy::uninlined_format_args,
-    clippy::impl_trait_in_params
+    clippy::uninlined_format_args
 )]
 
 use std::path::{Path, PathBuf};

tests/ui/eta.stderr

@@ -1,159 +1,159 @@
 error: redundant closure
-  --> $DIR/eta.rs:29:27
+  --> $DIR/eta.rs:28:27
    |
 LL |     let a = Some(1u8).map(|a| foo(a));
    |                           ^^^^^^^^^^ help: replace the closure with the function itself: `foo`
    |
    = note: `-D clippy::redundant-closure` implied by `-D warnings`
 
 error: redundant closure
-  --> $DIR/eta.rs:33:40
+  --> $DIR/eta.rs:32:40
    |
 LL |     let _: Option<Vec<u8>> = true.then(|| vec![]); // special case vec!
    |                                        ^^^^^^^^^ help: replace the closure with `Vec::new`: `std::vec::Vec::new`
 
 error: redundant closure
-  --> $DIR/eta.rs:34:35
+  --> $DIR/eta.rs:33:35
    |
 LL |     let d = Some(1u8).map(|a| foo((|b| foo2(b))(a))); //is adjusted?
    |                                   ^^^^^^^^^^^^^ help: replace the closure with the function itself: `foo2`
 
 error: redundant closure
-  --> $DIR/eta.rs:35:26
+  --> $DIR/eta.rs:34:26
    |
 LL |     all(&[1, 2, 3], &&2, |x, y| below(x, y)); //is adjusted
    |                          ^^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `below`
 
 error: redundant closure
-  --> $DIR/eta.rs:42:27
+  --> $DIR/eta.rs:41:27
    |
 LL |     let e = Some(1u8).map(|a| generic(a));
    |                           ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `generic`
 
 error: redundant closure
-  --> $DIR/eta.rs:88:51
+  --> $DIR/eta.rs:87:51
    |
 LL |     let e = Some(TestStruct { some_ref: &i }).map(|a| a.foo());
    |                                                   ^^^^^^^^^^^ help: replace the closure with the method itself: `TestStruct::foo`
    |
    = note: `-D clippy::redundant-closure-for-method-calls` implied by `-D warnings`
 
 error: redundant closure
-  --> $DIR/eta.rs:89:51
+  --> $DIR/eta.rs:88:51
    |
 LL |     let e = Some(TestStruct { some_ref: &i }).map(|a| a.trait_foo());
    |                                                   ^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `TestTrait::trait_foo`
 
 error: redundant closure
-  --> $DIR/eta.rs:91:42
+  --> $DIR/eta.rs:90:42
    |
 LL |     let e = Some(&mut vec![1, 2, 3]).map(|v| v.clear());
    |                                          ^^^^^^^^^^^^^ help: replace the closure with the method itself: `std::vec::Vec::clear`
 
 error: redundant closure
-  --> $DIR/eta.rs:95:29
+  --> $DIR/eta.rs:94:29
    |
 LL |     let e = Some("str").map(|s| s.to_string());
    |                             ^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `std::string::ToString::to_string`
 
 error: redundant closure
-  --> $DIR/eta.rs:96:27
+  --> $DIR/eta.rs:95:27
    |
 LL |     let e = Some('a').map(|s| s.to_uppercase());
    |                           ^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `char::to_uppercase`
 
 error: redundant closure
-  --> $DIR/eta.rs:98:65
+  --> $DIR/eta.rs:97:65
    |
 LL |     let e: std::vec::Vec<char> = vec!['a', 'b', 'c'].iter().map(|c| c.to_ascii_uppercase()).collect();
    |                                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `char::to_ascii_uppercase`
 
 error: redundant closure
-  --> $DIR/eta.rs:161:22
+  --> $DIR/eta.rs:160:22
    |
 LL |     requires_fn_once(|| x());
    |                      ^^^^^^ help: replace the closure with the function itself: `x`
 
 error: redundant closure
-  --> $DIR/eta.rs:168:27
+  --> $DIR/eta.rs:167:27
    |
 LL |     let a = Some(1u8).map(|a| foo_ptr(a));
    |                           ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `foo_ptr`
 
 error: redundant closure
-  --> $DIR/eta.rs:173:27
+  --> $DIR/eta.rs:172:27
    |
 LL |     let a = Some(1u8).map(|a| closure(a));
    |                           ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `closure`
 
 error: redundant closure
-  --> $DIR/eta.rs:205:28
+  --> $DIR/eta.rs:204:28
    |
 LL |     x.into_iter().for_each(|x| add_to_res(x));
    |                            ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut add_to_res`
 
 error: redundant closure
-  --> $DIR/eta.rs:206:28
+  --> $DIR/eta.rs:205:28
    |
 LL |     y.into_iter().for_each(|x| add_to_res(x));
    |                            ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut add_to_res`
 
 error: redundant closure
-  --> $DIR/eta.rs:207:28
+  --> $DIR/eta.rs:206:28
    |
 LL |     z.into_iter().for_each(|x| add_to_res(x));
    |                            ^^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `add_to_res`
 
 error: redundant closure
-  --> $DIR/eta.rs:214:21
+  --> $DIR/eta.rs:213:21
    |
 LL |         Some(1).map(|n| closure(n));
    |                     ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut closure`
 
 error: redundant closure
-  --> $DIR/eta.rs:218:21
+  --> $DIR/eta.rs:217:21
    |
 LL |         Some(1).map(|n| in_loop(n));
    |                     ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `in_loop`
 
 error: redundant closure
-  --> $DIR/eta.rs:311:18
+  --> $DIR/eta.rs:310:18
    |
 LL |     takes_fn_mut(|| f());
    |                  ^^^^^^ help: replace the closure with the function itself: `&mut f`
 
 error: redundant closure
-  --> $DIR/eta.rs:314:19
+  --> $DIR/eta.rs:313:19
    |
 LL |     takes_fn_once(|| f());
    |                   ^^^^^^ help: replace the closure with the function itself: `&mut f`
 
 error: redundant closure
-  --> $DIR/eta.rs:318:26
+  --> $DIR/eta.rs:317:26
    |
 LL |     move || takes_fn_mut(|| f_used_once())
    |                          ^^^^^^^^^^^^^^^^ help: replace the closure with the function itself: `&mut f_used_once`
 
 error: redundant closure
-  --> $DIR/eta.rs:330:19
+  --> $DIR/eta.rs:329:19
    |
 LL |     array_opt.map(|a| a.as_slice());
    |                   ^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<[u8; 3]>::as_slice`
 
 error: redundant closure
-  --> $DIR/eta.rs:333:19
+  --> $DIR/eta.rs:332:19
    |
 LL |     slice_opt.map(|s| s.len());
    |                   ^^^^^^^^^^^ help: replace the closure with the method itself: `<[u8]>::len`
 
 error: redundant closure
-  --> $DIR/eta.rs:336:17
+  --> $DIR/eta.rs:335:17
    |
 LL |     ptr_opt.map(|p| p.is_null());
    |                 ^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<*const usize>::is_null`
 
 error: redundant closure
-  --> $DIR/eta.rs:340:17
+  --> $DIR/eta.rs:339:17
    |
 LL |     dyn_opt.map(|d| d.method_on_dyn());
    |                 ^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `<dyn TestTrait>::method_on_dyn`