Address lints from clippy for beta/nightly (#5709)

* Fix clippy lints in tests

* Replace `format!` in `.push_str()` with `write!`

Stylistically that might be a bit rough but elides an allocation.

Fallibility of allocation is more explicit, but ignored with `let _ =`
like in the clippy example:

https://rust-lang.github.io/rust-clippy/master/index.html#format_push_string

* Remove unused lifetime

* Fix macro crate relative import

* Derive `Eq` for `PartialEq` with `Eq` members

https://rust-lang.github.io/rust-clippy/master/index.html#derive_partial_eq_without_eq

* Remove unnnecessary `.to_string()` for Cow<str>

* Remove `.to_string()` for `tendril::Tendril`

Implements `Deref<Target = str>`

crates/nu-cli/src/menus/help_completions.rs

@@ -1,6 +1,7 @@
 use nu_engine::documentation::get_flags_section;
 use nu_protocol::{engine::EngineState, levenshtein_distance};
 use reedline::{Completer, Suggestion};
+use std::fmt::Write;
 use std::sync::Arc;
 
 pub struct NuHelpCompleter(Arc<EngineState>);
@@ -53,7 +54,7 @@ impl NuHelpCompleter {
                     long_desc.push_str("\r\n\r\n");
                 }
 
-                long_desc.push_str(&format!("Usage:\r\n  > {}\r\n", sig.call_signature()));
+                let _ = write!(long_desc, "Usage:\r\n  > {}\r\n", sig.call_signature());
 
                 if !sig.named.is_empty() {
                     long_desc.push_str(&get_flags_section(sig))
@@ -65,21 +66,22 @@ impl NuHelpCompleter {
                 {
                     long_desc.push_str("\r\nParameters:\r\n");
                     for positional in &sig.required_positional {
-                        long_desc
-                            .push_str(&format!("  {}: {}\r\n", positional.name, positional.desc));
+                        let _ = write!(long_desc, "  {}: {}\r\n", positional.name, positional.desc);
                     }
                     for positional in &sig.optional_positional {
-                        long_desc.push_str(&format!(
+                        let _ = write!(
+                            long_desc,
                             "  (optional) {}: {}\r\n",
                             positional.name, positional.desc
-                        ));
+                        );
                     }
 
                     if let Some(rest_positional) = &sig.rest_positional {
-                        long_desc.push_str(&format!(
+                        let _ = write!(
+                            long_desc,
                             "  ...{}: {}\r\n",
                             rest_positional.name, rest_positional.desc
-                        ));
+                        );
                     }
                 }
 

crates/nu-cli/tests/custom_completions.rs

@@ -18,7 +18,7 @@ fn variables_completions() {
     let mut completer = NuCompleter::new(std::sync::Arc::new(engine), stack);
 
     // Test completions for $nu
-    let suggestions = completer.complete("my-command ".into(), 11);
+    let suggestions = completer.complete("my-command ", 11);
 
     assert_eq!(3, suggestions.len());
 

crates/nu-cli/tests/flag_completions.rs

@@ -12,7 +12,7 @@ fn flag_completions() {
     // Instatiate a new completer
     let mut completer = NuCompleter::new(std::sync::Arc::new(engine), stack);
     // Test completions for the 'ls' flags
-    let suggestions = completer.complete("ls -".into(), 4);
+    let suggestions = completer.complete("ls -", 4);
 
     assert_eq!(12, suggestions.len());
 

crates/nu-cli/tests/support/completions_helpers.rs

@@ -89,7 +89,7 @@ pub fn merge_input(
     dir: PathBuf,
 ) -> Result<(), ShellError> {
     let (block, delta) = {
-        let mut working_set = StateWorkingSet::new(&engine_state);
+        let mut working_set = StateWorkingSet::new(engine_state);
 
         let (block, err) = parse(&mut working_set, None, input, false, &[]);
 
@@ -98,7 +98,7 @@ pub fn merge_input(
         (block, working_set.render())
     };
     assert!(eval_block(
-        &engine_state,
+        engine_state,
         stack,
         &block,
         PipelineData::Value(

crates/nu-cli/tests/variables_completions.rs

@@ -17,7 +17,7 @@ fn variables_completions() {
     let mut completer = NuCompleter::new(std::sync::Arc::new(engine), stack);
 
     // Test completions for $nu
-    let suggestions = completer.complete("$nu.".into(), 4);
+    let suggestions = completer.complete("$nu.", 4);
 
     assert_eq!(8, suggestions.len());
 
@@ -36,7 +36,7 @@ fn variables_completions() {
     match_suggestions(expected, suggestions);
 
     // Test completions for $nu.h (filter)
-    let suggestions = completer.complete("$nu.h".into(), 5);
+    let suggestions = completer.complete("$nu.h", 5);
 
     assert_eq!(2, suggestions.len());
 
@@ -46,7 +46,7 @@ fn variables_completions() {
     match_suggestions(expected, suggestions);
 
     // Test completions for custom var
-    let suggestions = completer.complete("$actor.".into(), 7);
+    let suggestions = completer.complete("$actor.", 7);
 
     assert_eq!(2, suggestions.len());
 
@@ -56,7 +56,7 @@ fn variables_completions() {
     match_suggestions(expected, suggestions);
 
     // Test completions for custom var (filtering)
-    let suggestions = completer.complete("$actor.n".into(), 7);
+    let suggestions = completer.complete("$actor.n", 7);
 
     assert_eq!(1, suggestions.len());
 
@@ -66,7 +66,7 @@ fn variables_completions() {
     match_suggestions(expected, suggestions);
 
     // Test completions for $env
-    let suggestions = completer.complete("$env.".into(), 5);
+    let suggestions = completer.complete("$env.", 5);
 
     assert_eq!(2, suggestions.len());
 
@@ -76,7 +76,7 @@ fn variables_completions() {
     match_suggestions(expected, suggestions);
 
     // Test completions for $env
-    let suggestions = completer.complete("$env.T".into(), 5);
+    let suggestions = completer.complete("$env.T", 5);
 
     assert_eq!(1, suggestions.len());