Merge #1374

1374: Implement `cargo lint` and fix some clippy errors r=alanhdu a=alanhdu

This creates a `cargo lint` command that runs clippy with certain lints disabled. I've also gone ahead and fixed some of the lint errors, although there are many more still to go.

cc #848 

Co-authored-by: Alan Du <[email protected]>

11 files changed, 27 insertions, 23 deletions

diff --git a/crates/ra_ide_api/src/call_info.rs b/crates/ra_ide_api/src/call_info.rs
index 5d43282fd..bd08e183d 100644
--- a/crates/ra_ide_api/src/call_info.rs
+++ b/crates/ra_ide_api/src/call_info.rs
@@ -21,8 +21,7 @@ pub(crate) fn call_info(db: &RootDatabase, position: FilePosition) -> Option<Cal
     let function = match calling_node {
         FnCallNode::CallExpr(expr) => {
             //FIXME: apply subst
-            let (callable_def, _subst) =
-                analyzer.type_of(db, expr.expr()?.into())?.as_callable()?;
+            let (callable_def, _subst) = analyzer.type_of(db, expr.expr()?)?.as_callable()?;
             match callable_def {
                 hir::CallableDef::Function(it) => it,
                 //FIXME: handle other callables
@@ -64,7 +63,7 @@ pub(crate) fn call_info(db: &RootDatabase, position: FilePosition) -> Option<Cal
 
             // If we are in a method account for `self`
             if has_self {
-                param = param + 1;
+                param += 1;
             }
 
             call_info.active_parameter = Some(param);
diff --git a/crates/ra_ide_api/src/completion/complete_dot.rs b/crates/ra_ide_api/src/completion/complete_dot.rs
index 5bf289c63..0822a0e7e 100644
--- a/crates/ra_ide_api/src/completion/complete_dot.rs
+++ b/crates/ra_ide_api/src/completion/complete_dot.rs
@@ -16,8 +16,8 @@ pub(super) fn complete_dot(acc: &mut Completions, ctx: &CompletionContext) {
 
 fn complete_fields(acc: &mut Completions, ctx: &CompletionContext, receiver: Ty) {
     for receiver in receiver.autoderef(ctx.db) {
-        match receiver {
-            Ty::Apply(a_ty) => match a_ty.ctor {
+        if let Ty::Apply(a_ty) = receiver {
+            match a_ty.ctor {
                 TypeCtor::Adt(AdtDef::Struct(s)) => {
                     for field in s.fields(ctx.db) {
                         acc.add_field(ctx, field, &a_ty.parameters);
@@ -30,8 +30,7 @@ fn complete_fields(acc: &mut Completions, ctx: &CompletionContext, receiver: Ty)
                     }
                 }
                 _ => {}
-            },
-            _ => {}
+            }
         };
     }
 }
diff --git a/crates/ra_ide_api/src/completion/complete_pattern.rs b/crates/ra_ide_api/src/completion/complete_pattern.rs
index 74833a756..6655a05a7 100644
--- a/crates/ra_ide_api/src/completion/complete_pattern.rs
+++ b/crates/ra_ide_api/src/completion/complete_pattern.rs
@@ -10,7 +10,7 @@ pub(super) fn complete_pattern(acc: &mut Completions, ctx: &CompletionContext) {
     let names = ctx.analyzer.all_names(ctx.db);
     for (name, res) in names.into_iter() {
         let r = res.as_ref();
-        let def = match r.take_types().or(r.take_values()) {
+        let def = match r.take_types().or_else(|| r.take_values()) {
             Some(hir::Resolution::Def(def)) => def,
             _ => continue,
         };
diff --git a/crates/ra_ide_api/src/completion/complete_scope.rs b/crates/ra_ide_api/src/completion/complete_scope.rs
index 2473e58b4..0f8cfaae8 100644
--- a/crates/ra_ide_api/src/completion/complete_scope.rs
+++ b/crates/ra_ide_api/src/completion/complete_scope.rs
@@ -49,7 +49,7 @@ pub(super) fn complete_scope(acc: &mut Completions, ctx: &CompletionContext) {
     }
 }
 
-fn build_import_label(name: &str, path: &Vec<SmolStr>) -> String {
+fn build_import_label(name: &str, path: &[SmolStr]) -> String {
     let mut buf = String::with_capacity(64);
     buf.push_str(name);
     buf.push_str(" (");
@@ -58,7 +58,7 @@ fn build_import_label(name: &str, path: &Vec<SmolStr>) -> String {
     buf
 }
 
-fn fmt_import_path(path: &Vec<SmolStr>, buf: &mut String) {
+fn fmt_import_path(path: &[SmolStr], buf: &mut String) {
     let mut segments = path.iter();
     if let Some(s) = segments.next() {
         buf.push_str(&s);
diff --git a/crates/ra_ide_api/src/diagnostics.rs b/crates/ra_ide_api/src/diagnostics.rs
index a2a8c1e4f..35b3d77df 100644
--- a/crates/ra_ide_api/src/diagnostics.rs
+++ b/crates/ra_ide_api/src/diagnostics.rs
@@ -109,7 +109,7 @@ fn check_unnecessary_braces_in_use_statement(
 
         acc.push(Diagnostic {
             range,
-            message: format!("Unnecessary braces in use statement"),
+            message: "Unnecessary braces in use statement".to_string(),
             severity: Severity::WeakWarning,
             fix: Some(SourceChange::source_file_edit(
                 "Remove unnecessary braces",
@@ -155,7 +155,7 @@ fn check_struct_shorthand_initialization(
 
                 acc.push(Diagnostic {
                     range: named_field.syntax().range(),
-                    message: format!("Shorthand struct initialization"),
+                    message: "Shorthand struct initialization".to_string(),
                     severity: Severity::WeakWarning,
                     fix: Some(SourceChange::source_file_edit(
                         "use struct shorthand initialization",
diff --git a/crates/ra_ide_api/src/extend_selection.rs b/crates/ra_ide_api/src/extend_selection.rs
index 00c445310..a713b762c 100644
--- a/crates/ra_ide_api/src/extend_selection.rs
+++ b/crates/ra_ide_api/src/extend_selection.rs
@@ -95,7 +95,7 @@ fn extend_single_word_in_comment_or_string(
     }
 
     let start_idx = before.rfind(non_word_char)? as u32;
-    let end_idx = after.find(non_word_char).unwrap_or(after.len()) as u32;
+    let end_idx = after.find(non_word_char).unwrap_or_else(|| after.len()) as u32;
 
     let from: TextUnit = (start_idx + 1).into();
     let to: TextUnit = (cursor_position + end_idx).into();
diff --git a/crates/ra_ide_api/src/folding_ranges.rs b/crates/ra_ide_api/src/folding_ranges.rs
index b50bbee38..4400ff232 100644
--- a/crates/ra_ide_api/src/folding_ranges.rs
+++ b/crates/ra_ide_api/src/folding_ranges.rs
@@ -205,7 +205,7 @@ mod tests {
             "The amount of fold kinds is different than the expected amount"
         );
         for ((fold, range), fold_kind) in
-            folds.into_iter().zip(ranges.into_iter()).zip(fold_kinds.into_iter())
+            folds.iter().zip(ranges.into_iter()).zip(fold_kinds.iter())
         {
             assert_eq!(fold.range.start(), range.start());
             assert_eq!(fold.range.end(), range.end());
diff --git a/crates/ra_ide_api/src/hover.rs b/crates/ra_ide_api/src/hover.rs
index 9c35db2a4..f56965ef5 100644
--- a/crates/ra_ide_api/src/hover.rs
+++ b/crates/ra_ide_api/src/hover.rs
@@ -18,6 +18,12 @@ pub struct HoverResult {
     exact: bool,
 }
 
+impl Default for HoverResult {
+    fn default() -> Self {
+        HoverResult::new()
+    }
+}
+
 impl HoverResult {
     pub fn new() -> HoverResult {
         HoverResult {
diff --git a/crates/ra_ide_api/src/line_index.rs b/crates/ra_ide_api/src/line_index.rs
index fd33d6767..087dfafed 100644
--- a/crates/ra_ide_api/src/line_index.rs
+++ b/crates/ra_ide_api/src/line_index.rs
@@ -41,7 +41,7 @@ impl LineIndex {
                 newlines.push(curr_row);
 
                 // Save any utf-16 characters seen in the previous line
-                if utf16_chars.len() > 0 {
+                if !utf16_chars.is_empty() {
                     utf16_lines.insert(line, utf16_chars);
                     utf16_chars = Vec::new();
                 }
@@ -61,7 +61,7 @@ impl LineIndex {
         }
 
         // Save any utf-16 characters seen in the last line
-        if utf16_chars.len() > 0 {
+        if !utf16_chars.is_empty() {
             utf16_lines.insert(line, utf16_chars);
         }
 
diff --git a/crates/ra_ide_api/src/line_index_utils.rs b/crates/ra_ide_api/src/line_index_utils.rs
index 799a920ad..a03467011 100644
--- a/crates/ra_ide_api/src/line_index_utils.rs
+++ b/crates/ra_ide_api/src/line_index_utils.rs
@@ -133,9 +133,9 @@ impl<'a> Edits<'a> {
     }
 
     fn next_steps(&mut self, step: &Step) -> NextSteps {
-        let step_pos = match step {
-            &Step::Newline(n) => n,
-            &Step::Utf16Char(r) => r.end(),
+        let step_pos = match *step {
+            Step::Newline(n) => n,
+            Step::Utf16Char(r) => r.end(),
         };
         let res = match &mut self.current {
             Some(edit) => {
@@ -181,9 +181,9 @@ impl<'a> Edits<'a> {
         if self.acc_diff == 0 {
             x.clone()
         } else {
-            match x {
-                &Step::Newline(n) => Step::Newline(self.translate(n)),
-                &Step::Utf16Char(r) => Step::Utf16Char(self.translate_range(r)),
+            match *x {
+                Step::Newline(n) => Step::Newline(self.translate(n)),
+                Step::Utf16Char(r) => Step::Utf16Char(self.translate_range(r)),
             }
         }
     }
diff --git a/crates/ra_ide_api/src/typing.rs b/crates/ra_ide_api/src/typing.rs
index 63bc0cf88..3e35d8352 100644
--- a/crates/ra_ide_api/src/typing.rs
+++ b/crates/ra_ide_api/src/typing.rs
@@ -110,7 +110,7 @@ pub(crate) fn on_dot_typed(db: &RootDatabase, position: FilePosition) -> Option<
     let mut edit = TextEditBuilder::default();
     edit.replace(
         TextRange::from_to(position.offset - current_indent_len, position.offset),
-        target_indent.into(),
+        target_indent,
     );
 
     let res = SourceChange::source_file_edit_from("reindent dot", position.file_id, edit.finish())