Remove unnecessary #[allow(...)] annotations (#6870)

* Remove unnecessary `#[allow]` annots

Reduce the number of lint exceptions that are not necessary with the
current state of the code (or more recent toolchain)

* Remove dead code from `FileStructure` in nu-command

* Replace `allow(unused)` with relevant feature switch

* Deal with `needless_collect` with annotations

* Change hack for needless_collect in `from json`

This change obviates the need for `allow(needless_collect)`
Removes a pessimistic allocation for empty strings, but increases
allocation size to `Value`

Probably not really worth it.

* Revert "Deal with `needless_collect` with annotations"

This reverts commit 05aca98445.

The previous state seems to better from a performance perspective as a
`Vec<String>` is lighter weight than `Vec<Value>`

crates/nu-command/src/dataframe/eager/columns.rs

@@ -55,7 +55,6 @@ impl Command for ColumnsDF {
     }
 }
 
-#[allow(clippy::needless_collect)]
 fn command(
     _engine_state: &EngineState,
     _stack: &mut Stack,

crates/nu-command/src/dataframe/eager/dtypes.rs

@@ -56,7 +56,6 @@ impl Command for DataTypes {
     }
 }
 
-#[allow(clippy::needless_collect)]
 fn command(
     _engine_state: &EngineState,
     _stack: &mut Stack,

crates/nu-command/src/filesystem/cp.rs

@@ -25,7 +25,6 @@ const GLOB_PARAMS: nu_glob::MatchOptions = nu_glob::MatchOptions {
 #[derive(Clone)]
 pub struct Cp;
 
-#[allow(unused_must_use)]
 impl Command for Cp {
     fn name(&self) -> &str {
         "cp"

crates/nu-command/src/filesystem/mv.rs

@@ -20,7 +20,6 @@ const GLOB_PARAMS: nu_glob::MatchOptions = nu_glob::MatchOptions {
 #[derive(Clone)]
 pub struct Mv;
 
-#[allow(unused_must_use)]
 impl Command for Mv {
     fn name(&self) -> &str {
         "mv"

crates/nu-command/src/filesystem/util.rs

@@ -14,20 +14,11 @@ pub struct FileStructure {
     pub resources: Vec<Resource>,
 }
 
-#[allow(dead_code)]
 impl FileStructure {
     pub fn new() -> FileStructure {
         FileStructure { resources: vec![] }
     }
 
-    pub fn contains_more_than_one_file(&self) -> bool {
-        self.resources.len() > 1
-    }
-
-    pub fn contains_files(&self) -> bool {
-        !self.resources.is_empty()
-    }
-
     pub fn paths_applying_with<F>(
         &mut self,
         to: F,

crates/nu-command/src/filters/group_by.rs

@@ -38,7 +38,6 @@ impl Command for GroupBy {
         group_by(engine_state, stack, call, input)
     }
 
-    #[allow(clippy::unwrap_used)]
     fn examples(&self) -> Vec<Example> {
         vec![
             Example {

crates/nu-command/src/filters/split_by.rs

@@ -35,7 +35,6 @@ impl Command for SplitBy {
         split_by(engine_state, stack, call, input)
     }
 
-    #[allow(clippy::unwrap_used)]
     fn examples(&self) -> Vec<Example> {
         vec![Example {
             description: "split items by column named \"lang\"",

crates/nu-command/src/formats/from/json.rs

@@ -84,21 +84,20 @@ impl Command for FromJson {
 
         // TODO: turn this into a structured underline of the nu_json error
         if call.has_flag("objects") {
-            #[allow(clippy::needless_collect)]
-            let lines: Vec<String> = string_input.lines().map(|x| x.to_string()).collect();
-            Ok(lines
-                .into_iter()
+            let converted_lines: Vec<Value> = string_input
+                .lines()
                 .filter_map(move |x| {
                     if x.trim() == "" {
                         None
                     } else {
-                        match convert_string_to_value(x, span) {
+                        match convert_string_to_value(x.to_string(), span) {
                             Ok(v) => Some(v),
                             Err(error) => Some(Value::Error { error }),
                         }
                     }
                 })
-                .into_pipeline_data(engine_state.ctrlc.clone()))
+                .collect();
+            Ok(converted_lines.into_pipeline_data(engine_state.ctrlc.clone()))
         } else {
             Ok(convert_string_to_value(string_input, span)?.into_pipeline_data())
         }

crates/nu-command/src/formats/to/md.rs

@@ -270,15 +270,10 @@ fn get_output_string(
 
         output_string.push_str("\n|");
 
-        #[allow(clippy::needless_range_loop)]
-        for i in 0..headers.len() {
+        for &col_width in column_widths.iter().take(headers.len()) {
             if pretty {
                 output_string.push(' ');
-                output_string.push_str(&get_padded_string(
-                    String::from("-"),
-                    column_widths[i],
-                    '-',
-                ));
+                output_string.push_str(&get_padded_string(String::from("-"), col_width, '-'));
                 output_string.push(' ');
             } else {
                 output_string.push('-');

crates/nu-command/src/math/reducers.rs

@@ -1,7 +1,6 @@
 use nu_protocol::{ShellError, Span, Value};
 use std::cmp::Ordering;
 
-#[allow(dead_code)]
 pub enum Reduce {
     Summation,
     Product,

crates/nu-command/src/viewers/table.rs

@@ -774,7 +774,6 @@ fn convert_to_table(
 }
 
 #[allow(clippy::too_many_arguments)]
-#[allow(clippy::into_iter_on_ref)]
 fn convert_to_table2<'a>(
     row_offset: usize,
     input: impl Iterator<Item = &'a Value> + ExactSizeIterator + Clone,

crates/nu-command/tests/commands/where_.rs

@@ -1,5 +1,5 @@
 use nu_test_support::nu;
-#[allow(unused)]
+#[cfg(feature = "database")]
 use nu_test_support::pipeline;
 
 #[test]

crates/nu-glob/src/lib.rs

@@ -863,7 +863,6 @@ fn chars_eq(a: char, b: char, case_sensitive: bool) -> bool {
 }
 
 /// Configuration options to modify the behaviour of `Pattern::matches_with(..)`.
-#[allow(missing_copy_implementations)]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
 pub struct MatchOptions {
     /// Whether or not patterns should be matched in a case-sensitive manner.

crates/nu-parser/src/parser.rs

@@ -1604,7 +1604,6 @@ pub fn parse_string_interpolation(
 
     let mut b = start;
 
-    #[allow(clippy::needless_range_loop)]
     while b != end {
         if contents[b - start] == b'('
             && (if double_quote && (b - start) > 0 {

src/main.rs

@@ -606,7 +606,6 @@ fn parse_commandline_args(
 
 struct NushellCliArgs {
     redirect_stdin: Option<Spanned<String>>,
-    #[allow(dead_code)]
     login_shell: Option<Spanned<String>>,
     interactive_shell: Option<Spanned<String>>,
     commands: Option<Spanned<String>>,