remove useless conversions

crates/hir-def/src/nameres/collector.rs

@@ -67,7 +67,7 @@ pub(super) fn collect_defs(db: &dyn DefDatabase, mut def_map: DefMap, tree_id: T
         let dep_def_map = db.crate_def_map(dep.crate_id);
         let dep_root = dep_def_map.module_id(dep_def_map.root);
 
-        deps.insert(dep.as_name(), dep_root.into());
+        deps.insert(dep.as_name(), dep_root);
 
         if dep.is_prelude() && !tree_id.is_block() {
             def_map.extern_prelude.insert(dep.as_name(), dep_root);
@@ -2085,7 +2085,7 @@ impl ModCollector<'_, '_> {
                                 .scope
                                 .get_legacy_macro(name)
                                 .and_then(|it| it.last())
-                                .map(|&it| macro_id_to_def_id(self.def_collector.db, it.into()))
+                                .map(|&it| macro_id_to_def_id(self.def_collector.db, it))
                         },
                     )
                 })

crates/hir-def/src/nameres/path_resolution.rs

@@ -390,7 +390,7 @@ impl DefMap {
             .get_legacy_macro(name)
             // FIXME: shadowing
             .and_then(|it| it.last())
-            .map_or_else(PerNs::none, |&m| PerNs::macros(m.into(), Visibility::Public));
+            .map_or_else(PerNs::none, |&m| PerNs::macros(m, Visibility::Public));
         let from_scope = self[module].scope.get(name);
         let from_builtin = match self.block {
             Some(_) => {

crates/hir-def/src/resolver.rs

@@ -381,7 +381,7 @@ impl Resolver {
         });
         def_map[module_id].scope.legacy_macros().for_each(|(name, macs)| {
             macs.iter().for_each(|&mac| {
-                res.add(name, ScopeDef::ModuleDef(ModuleDefId::MacroId(MacroId::from(mac))));
+                res.add(name, ScopeDef::ModuleDef(ModuleDefId::MacroId(mac)));
             })
         });
         def_map.extern_prelude().for_each(|(name, &def)| {
@@ -517,10 +517,7 @@ impl Scope {
                 });
                 m.def_map[m.module_id].scope.legacy_macros().for_each(|(name, macs)| {
                     macs.iter().for_each(|&mac| {
-                        acc.add(
+                        acc.add(name, ScopeDef::ModuleDef(ModuleDefId::MacroId(mac)));
-                            name,
-                            ScopeDef::ModuleDef(ModuleDefId::MacroId(MacroId::from(mac))),
-                        );
                     })
                 });
             }

crates/hir-ty/src/consteval/tests.rs

@@ -25,7 +25,6 @@ fn eval_goal(ra_fixture: &str) -> Result<ComputedExpr, ConstEvalError> {
     let scope = &def_map[module_id.local_id].scope;
     let const_id = scope
         .declarations()
-        .into_iter()
         .find_map(|x| match x {
             hir_def::ModuleDefId::ConstId(x) => {
                 if db.const_data(x).name.as_ref()?.to_string() == "GOAL" {

crates/hir-ty/src/infer/expr.rs

@@ -960,7 +960,7 @@ impl<'a> InferenceContext<'a> {
             Expr::RecordLit { path, fields, .. } => {
                 let subs = fields.iter().map(|f| (f.name.clone(), f.expr));
 
-                self.infer_record_pat_like(path.as_deref(), &rhs_ty, (), lhs.into(), subs)
+                self.infer_record_pat_like(path.as_deref(), &rhs_ty, (), lhs, subs)
             }
             Expr::Underscore => rhs_ty.clone(),
             _ => {

crates/hir-ty/src/infer/pat.rs

@@ -220,7 +220,7 @@ impl<'a> InferenceContext<'a> {
                 ),
             Pat::Record { path: p, args: fields, ellipsis: _ } => {
                 let subs = fields.iter().map(|f| (f.name.clone(), f.pat));
-                self.infer_record_pat_like(p.as_deref(), &expected, default_bm, pat.into(), subs)
+                self.infer_record_pat_like(p.as_deref(), &expected, default_bm, pat, subs)
             }
             Pat::Path(path) => {
                 // FIXME use correct resolver for the surrounding expression

crates/hir-ty/src/layout/tests.rs

@@ -29,7 +29,6 @@ fn eval_goal(ra_fixture: &str, minicore: &str) -> Result<Layout, LayoutError> {
     let scope = &def_map[module_id.local_id].scope;
     let adt_id = scope
         .declarations()
-        .into_iter()
         .find_map(|x| match x {
             hir_def::ModuleDefId::AdtId(x) => {
                 let name = match x {

crates/hir/src/lib.rs

@@ -608,7 +608,7 @@ impl Module {
     pub fn legacy_macros(self, db: &dyn HirDatabase) -> Vec<Macro> {
         let def_map = self.id.def_map(db.upcast());
         let scope = &def_map[self.id.local_id].scope;
-        scope.legacy_macros().flat_map(|(_, it)| it).map(|&it| MacroId::from(it).into()).collect()
+        scope.legacy_macros().flat_map(|(_, it)| it).map(|&it| it.into()).collect()
     }
 
     pub fn impl_defs(self, db: &dyn HirDatabase) -> Vec<Impl> {
@@ -2411,7 +2411,7 @@ pub struct DeriveHelper {
 
 impl DeriveHelper {
     pub fn derive(&self) -> Macro {
-        Macro { id: self.derive.into() }
+        Macro { id: self.derive }
     }
 
     pub fn name(&self, db: &dyn HirDatabase) -> Name {
@@ -2781,7 +2781,7 @@ impl Impl {
     pub fn all_for_trait(db: &dyn HirDatabase, trait_: Trait) -> Vec<Impl> {
         let krate = trait_.module(db).krate();
         let mut all = Vec::new();
-        for Crate { id } in krate.transitive_reverse_dependencies(db).into_iter() {
+        for Crate { id } in krate.transitive_reverse_dependencies(db) {
             let impls = db.trait_impls_in_crate(id);
             all.extend(impls.for_trait(trait_.id).map(Self::from))
         }

crates/hir/src/source_analyzer.rs

@@ -270,7 +270,7 @@ impl SourceAnalyzer {
         db: &dyn HirDatabase,
         await_expr: &ast::AwaitExpr,
     ) -> Option<FunctionId> {
-        let mut ty = self.ty_of_expr(db, &await_expr.expr()?.into())?.clone();
+        let mut ty = self.ty_of_expr(db, &await_expr.expr()?)?.clone();
 
         let into_future_trait = self
             .resolver
@@ -316,7 +316,7 @@ impl SourceAnalyzer {
             ast::UnaryOp::Not => name![not],
             ast::UnaryOp::Neg => name![neg],
         };
-        let ty = self.ty_of_expr(db, &prefix_expr.expr()?.into())?;
+        let ty = self.ty_of_expr(db, &prefix_expr.expr()?)?;
 
         let (op_trait, op_fn) = self.lang_trait_fn(db, &lang_item_name, &lang_item_name)?;
         // HACK: subst for all methods coincides with that for their trait because the methods
@@ -331,8 +331,8 @@ impl SourceAnalyzer {
         db: &dyn HirDatabase,
         index_expr: &ast::IndexExpr,
     ) -> Option<FunctionId> {
-        let base_ty = self.ty_of_expr(db, &index_expr.base()?.into())?;
+        let base_ty = self.ty_of_expr(db, &index_expr.base()?)?;
-        let index_ty = self.ty_of_expr(db, &index_expr.index()?.into())?;
+        let index_ty = self.ty_of_expr(db, &index_expr.index()?)?;
 
         let lang_item_name = name![index];
 
@@ -352,8 +352,8 @@ impl SourceAnalyzer {
         binop_expr: &ast::BinExpr,
     ) -> Option<FunctionId> {
         let op = binop_expr.op_kind()?;
-        let lhs = self.ty_of_expr(db, &binop_expr.lhs()?.into())?;
+        let lhs = self.ty_of_expr(db, &binop_expr.lhs()?)?;
-        let rhs = self.ty_of_expr(db, &binop_expr.rhs()?.into())?;
+        let rhs = self.ty_of_expr(db, &binop_expr.rhs()?)?;
 
         let (op_trait, op_fn) = lang_names_for_bin_op(op)
             .and_then(|(name, lang_item)| self.lang_trait_fn(db, &lang_item, &name))?;
@@ -372,7 +372,7 @@ impl SourceAnalyzer {
         db: &dyn HirDatabase,
         try_expr: &ast::TryExpr,
     ) -> Option<FunctionId> {
-        let ty = self.ty_of_expr(db, &try_expr.expr()?.into())?;
+        let ty = self.ty_of_expr(db, &try_expr.expr()?)?;
 
         let op_fn =
             db.lang_item(self.resolver.krate(), name![branch].to_smol_str())?.as_function()?;

crates/ide-assists/src/handlers/generate_default_from_new.rs

@@ -53,7 +53,7 @@ pub(crate) fn generate_default_from_new(acc: &mut Assists, ctx: &AssistContext<'
         return None;
     }
 
-    let impl_ = fn_node.syntax().ancestors().into_iter().find_map(ast::Impl::cast)?;
+    let impl_ = fn_node.syntax().ancestors().find_map(ast::Impl::cast)?;
     if is_default_implemented(ctx, &impl_) {
         cov_mark::hit!(default_block_is_already_present);
         cov_mark::hit!(struct_in_module_with_default);

crates/ide-assists/src/handlers/generate_deref.rs

@@ -85,8 +85,7 @@ fn generate_tuple_deref(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()
     let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
     let field = ctx.find_node_at_offset::<ast::TupleField>()?;
     let field_list = ctx.find_node_at_offset::<ast::TupleFieldList>()?;
-    let field_list_index =
+    let field_list_index = field_list.syntax().children().position(|s| &s == field.syntax())?;
-        field_list.syntax().children().into_iter().position(|s| &s == field.syntax())?;
 
     let deref_type_to_generate = match existing_deref_impl(&ctx.sema, &strukt) {
         None => DerefType::Deref,

crates/ide-assists/src/handlers/replace_turbofish_with_explicit_type.rs

@@ -42,7 +42,7 @@ pub(crate) fn replace_turbofish_with_explicit_type(
     let r_angle = generic_args.r_angle_token()?;
     let turbofish_range = TextRange::new(colon2.text_range().start(), r_angle.text_range().end());
 
-    let turbofish_args: Vec<GenericArg> = generic_args.generic_args().into_iter().collect();
+    let turbofish_args: Vec<GenericArg> = generic_args.generic_args().collect();
 
     // Find type of ::<_>
     if turbofish_args.len() != 1 {

crates/ide-completion/src/tests.rs

@@ -183,7 +183,7 @@ pub(crate) fn check_edit_with_config(
     let ra_fixture_after = trim_indent(ra_fixture_after);
     let (db, position) = position(ra_fixture_before);
     let completions: Vec<CompletionItem> =
-        crate::completions(&db, &config, position, None).unwrap().into();
+        crate::completions(&db, &config, position, None).unwrap();
     let (completion,) = completions
         .iter()
         .filter(|it| it.lookup() == what)

crates/ide/src/rename.rs

@@ -364,11 +364,8 @@ mod tests {
             }
             Err(err) => {
                 if ra_fixture_after.starts_with("error:") {
-                    let error_message = ra_fixture_after
+                    let error_message =
-                        .chars()
+                        ra_fixture_after.chars().skip("error:".len()).collect::<String>();
-                        .into_iter()
-                        .skip("error:".len())
-                        .collect::<String>();
                     assert_eq!(error_message.trim(), err.to_string());
                 } else {
                     panic!("Rename to '{new_name}' failed unexpectedly: {err}")

crates/mbe/src/syntax_bridge.rs

@@ -145,7 +145,7 @@ pub fn parse_exprs_with_sep(tt: &tt::Subtree, sep: char) -> Vec<tt::Subtree> {
     }
 
     if iter.peek_n(0).is_some() {
-        res.push(tt::Subtree { delimiter: None, token_trees: iter.into_iter().cloned().collect() });
+        res.push(tt::Subtree { delimiter: None, token_trees: iter.cloned().collect() });
     }
 
     res

crates/rust-analyzer/src/diagnostics.rs

@@ -101,8 +101,7 @@ impl DiagnosticCollection {
         file_id: FileId,
     ) -> impl Iterator<Item = &lsp_types::Diagnostic> {
         let native = self.native.get(&file_id).into_iter().flatten();
-        let check =
+        let check = self.check.values().filter_map(move |it| it.get(&file_id)).flatten();
-            self.check.values().filter_map(move |it| it.get(&file_id)).into_iter().flatten();
         native.chain(check)
     }
 

crates/rust-analyzer/src/handlers.rs

@@ -1101,9 +1101,7 @@ pub(crate) fn handle_code_action(
     }
 
     // Fixes from `cargo check`.
-    for fix in
+    for fix in snap.check_fixes.values().filter_map(|it| it.get(&frange.file_id)).flatten() {
-        snap.check_fixes.values().filter_map(|it| it.get(&frange.file_id)).into_iter().flatten()
-    {
         // FIXME: this mapping is awkward and shouldn't exist. Refactor
         // `snap.check_fixes` to not convert to LSP prematurely.
         let intersect_fix_range = fix