Auto merge of #54151 - ljedrz:cleanup_hir, r=michaelwoerister

A few cleanups for hir

- prefer `if let` to `match` when only 1 branch matters
- `chain` iterable items that are looped over in sequence
- `sort_by_key` instead of `sort_by` when possible
- change cloning `map`s to `cloned()`
- use `unwrap_or_else` and `ok` when applicable
- a few other minor readability improvements
- whitespace fixes

Author: bors

src/librustc/hir/check_attr.rs

@@ -125,7 +125,7 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
             .iter()
             .filter(|attr| attr.name() == "repr")
             .filter_map(|attr| attr.meta_item_list())
-            .flat_map(|hints| hints)
+            .flatten()
             .collect();
 
         let mut int_reprs = 0;
@@ -185,7 +185,7 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
                         continue
                     }
                 }
-                "i8" | "u8" | "i16" | "u16" |
+                "i8"  | "u8"  | "i16" | "u16" |
                 "i32" | "u32" | "i64" | "u64" |
                 "isize" | "usize" => {
                     int_reprs += 1;

src/librustc/hir/intravisit.rs

@@ -50,7 +50,6 @@ use super::itemlikevisit::DeepVisitor;
 
 use std::cmp;
 use std::u32;
-use std::result::Result::Err;
 
 #[derive(Copy, Clone)]
 pub enum FnKind<'a> {
@@ -1067,31 +1066,26 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
         ExprKind::Break(ref destination, ref opt_expr) => {
             if let Some(ref label) = destination.label {
                 visitor.visit_label(label);
-                match destination.target_id {
-                    Ok(node_id) => visitor.visit_def_mention(Def::Label(node_id)),
-                    Err(_) => {},
-                };
+                if let Ok(node_id) = destination.target_id {
+                    visitor.visit_def_mention(Def::Label(node_id))
+                }
             }
             walk_list!(visitor, visit_expr, opt_expr);
         }
         ExprKind::Continue(ref destination) => {
             if let Some(ref label) = destination.label {
                 visitor.visit_label(label);
-                match destination.target_id {
-                    Ok(node_id) => visitor.visit_def_mention(Def::Label(node_id)),
-                    Err(_) => {},
-                };
+                if let Ok(node_id) = destination.target_id {
+                    visitor.visit_def_mention(Def::Label(node_id))
+                }
             }
         }
         ExprKind::Ret(ref optional_expression) => {
             walk_list!(visitor, visit_expr, optional_expression);
         }
         ExprKind::InlineAsm(_, ref outputs, ref inputs) => {
-            for output in outputs {
-                visitor.visit_expr(output)
-            }
-            for input in inputs {
-                visitor.visit_expr(input)
+            for expr in outputs.iter().chain(inputs.iter()) {
+                visitor.visit_expr(expr)
             }
         }
         ExprKind::Yield(ref subexpression) => {
@@ -1156,7 +1150,6 @@ impl IdRange {
         self.min = cmp::min(self.min, id);
         self.max = cmp::max(self.max, NodeId::from_u32(id.as_u32() + 1));
     }
-
 }
 
 

src/librustc/hir/lowering.rs

@@ -597,7 +597,7 @@ impl<'a> LoweringContext<'a> {
         })
     }
 
-    fn expect_full_def_from_use(&mut self, id: NodeId) -> impl Iterator<Item=Def> {
+    fn expect_full_def_from_use(&mut self, id: NodeId) -> impl Iterator<Item = Def> {
         self.resolver.get_import(id).present_items().map(|pr| {
             if pr.unresolved_segments() != 0 {
                 bug!("path not fully resolved: {:?}", pr);
@@ -990,7 +990,7 @@ impl<'a> LoweringContext<'a> {
             None => {
                 self.loop_scopes
                     .last()
-                    .map(|innermost_loop_id| *innermost_loop_id)
+                    .cloned()
                     .map(|id| Ok(self.lower_node_id(id).node_id))
                     .unwrap_or(Err(hir::LoopIdError::OutsideLoopScope))
                     .into()

src/librustc/hir/map/blocks.rs

@@ -161,27 +161,27 @@ impl<'a> FnLikeNode<'a> {
     }
 
     pub fn body(self) -> ast::BodyId {
-        self.handle(|i: ItemFnParts<'a>|  i.body,
-                    |_, _, _: &'a ast::MethodSig, _, body: ast::BodyId, _, _|  body,
+        self.handle(|i: ItemFnParts<'a>| i.body,
+                    |_, _, _: &'a ast::MethodSig, _, body: ast::BodyId, _, _| body,
                     |c: ClosureParts<'a>| c.body)
     }
 
     pub fn decl(self) -> &'a FnDecl {
-        self.handle(|i: ItemFnParts<'a>|  &*i.decl,
-                    |_, _, sig: &'a ast::MethodSig, _, _, _, _|  &sig.decl,
+        self.handle(|i: ItemFnParts<'a>| &*i.decl,
+                    |_, _, sig: &'a ast::MethodSig, _, _, _, _| &sig.decl,
                     |c: ClosureParts<'a>| c.decl)
     }
 
     pub fn span(self) -> Span {
-        self.handle(|i: ItemFnParts|     i.span,
+        self.handle(|i: ItemFnParts| i.span,
                     |_, _, _: &'a ast::MethodSig, _, _, span, _| span,
-                    |c: ClosureParts|    c.span)
+                    |c: ClosureParts| c.span)
     }
 
     pub fn id(self) -> NodeId {
-        self.handle(|i: ItemFnParts|     i.id,
+        self.handle(|i: ItemFnParts| i.id,
                     |id, _, _: &'a ast::MethodSig, _, _, _, _| id,
-                    |c: ClosureParts|    c.id)
+                    |c: ClosureParts| c.id)
     }
 
     pub fn constness(self) -> ast::Constness {
@@ -260,9 +260,7 @@ impl<'a> FnLikeNode<'a> {
                     ast::ImplItemKind::Method(ref sig, body) => {
                         method(ii.id, ii.ident, sig, Some(&ii.vis), body, ii.span, &ii.attrs)
                     }
-                    _ => {
-                        bug!("impl method FnLikeNode that is not fn-like")
-                    }
+                    _ => bug!("impl method FnLikeNode that is not fn-like")
                 }
             },
             map::Node::Expr(e) => match e.node {

src/librustc/hir/map/collector.rs

@@ -67,7 +67,6 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
                 // them explicitly here.
                 ref attrs,
                 span,
-
                 // These fields are handled separately:
                 exported_macros: _,
                 items: _,
@@ -128,30 +127,27 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
                                                   cstore: &dyn CrateStore,
                                                   source_map: &SourceMap,
                                                   commandline_args_hash: u64)
-                                                  -> (Vec<Option<Entry<'hir>>>, Svh) {
-        self.hir_body_nodes
-            .sort_unstable_by(|&(ref d1, _), &(ref d2, _)| d1.cmp(d2));
+                                                  -> (Vec<Option<Entry<'hir>>>, Svh)
+    {
+        self.hir_body_nodes.sort_unstable_by_key(|bn| bn.0);
 
         let node_hashes = self
             .hir_body_nodes
             .iter()
-            .fold(Fingerprint::ZERO, |fingerprint , &(def_path_hash, dep_node_index)| {
+            .fold(Fingerprint::ZERO, |fingerprint, &(def_path_hash, dep_node_index)| {
                 fingerprint.combine(
                     def_path_hash.0.combine(self.dep_graph.fingerprint_of(dep_node_index))
                 )
             });
 
         let mut upstream_crates: Vec<_> = cstore.crates_untracked().iter().map(|&cnum| {
             let name = cstore.crate_name_untracked(cnum).as_str();
-            let disambiguator = cstore.crate_disambiguator_untracked(cnum)
-                                      .to_fingerprint();
+            let disambiguator = cstore.crate_disambiguator_untracked(cnum).to_fingerprint();
             let hash = cstore.crate_hash_untracked(cnum);
             (name, disambiguator, hash)
         }).collect();
 
-        upstream_crates.sort_unstable_by(|&(name1, dis1, _), &(name2, dis2, _)| {
-            (name1, dis1).cmp(&(name2, dis2))
-        });
+        upstream_crates.sort_unstable_by_key(|&(name, dis, _)| (name, dis));
 
         // We hash the final, remapped names of all local source files so we
         // don't have to include the path prefix remapping commandline args.
@@ -229,7 +225,6 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
         }
 
         self.insert_entry(id, entry);
-
     }
 
     fn with_parent<F: FnOnce(&mut Self)>(&mut self, parent_id: NodeId, f: F) {
@@ -311,14 +306,11 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         self.with_dep_node_owner(i.hir_id.owner, i, |this| {
             this.insert(i.id, Node::Item(i));
             this.with_parent(i.id, |this| {
-                match i.node {
-                    ItemKind::Struct(ref struct_def, _) => {
-                        // If this is a tuple-like struct, register the constructor.
-                        if !struct_def.is_struct() {
-                            this.insert(struct_def.id(), Node::StructCtor(struct_def));
-                        }
+                if let ItemKind::Struct(ref struct_def, _) = i.node {
+                    // If this is a tuple-like struct, register the constructor.
+                    if !struct_def.is_struct() {
+                        this.insert(struct_def.id(), Node::StructCtor(struct_def));
                     }
-                    _ => {}
                 }
                 intravisit::walk_item(this, i);
             });

src/librustc/hir/map/def_collector.rs

@@ -348,13 +348,10 @@ impl<'a> visit::Visitor<'a> for DefCollector<'a> {
 
     fn visit_token(&mut self, t: Token) {
         if let Token::Interpolated(nt) = t {
-            match nt.0 {
-                token::NtExpr(ref expr) => {
-                    if let ExprKind::Mac(..) = expr.node {
-                        self.visit_macro_invoc(expr.id);
-                    }
+            if let token::NtExpr(ref expr) = nt.0 {
+                if let ExprKind::Mac(..) = expr.node {
+                    self.visit_macro_invoc(expr.id);
                 }
-                _ => {}
             }
         }
     }

src/librustc/hir/map/definitions.rs

@@ -317,10 +317,8 @@ pub enum DefPathData {
     // they are treated specially by the `def_path` function.
     /// The crate root (marker)
     CrateRoot,
-
     // Catch-all for random DefId things like DUMMY_NODE_ID
     Misc,
-
     // Different kinds of items and item-like things:
     /// An impl
     Impl,
@@ -342,7 +340,6 @@ pub enum DefPathData {
     MacroDef(InternedString),
     /// A closure expression
     ClosureExpr,
-
     // Subportions of items
     /// A type parameter (generic parameter)
     TypeParam(InternedString),
@@ -358,7 +355,6 @@ pub enum DefPathData {
     AnonConst,
     /// An `impl Trait` type node
     ImplTrait,
-
     /// GlobalMetaData identifies a piece of crate metadata that is global to
     /// a whole crate (as opposed to just one item). GlobalMetaData components
     /// are only supposed to show up right below the crate root.
@@ -656,10 +652,8 @@ impl DefPathData {
             GlobalMetaData(name) => {
                 return name
             }
-
             // note that this does not show up in user printouts
             CrateRoot => "{{root}}",
-
             Impl => "{{impl}}",
             Misc => "{{?}}",
             ClosureExpr => "{{closure}}",

src/librustc/hir/map/hir_id_validator.rs

@@ -100,8 +100,8 @@ impl<'a, 'hir: 'a> HirIdValidator<'a, 'hir> {
 
         if max != self.hir_ids_seen.len() - 1 {
             // Collect the missing ItemLocalIds
-            let missing: Vec<_> = (0 .. max + 1)
-              .filter(|&i| !self.hir_ids_seen.contains_key(&ItemLocalId(i as u32)))
+            let missing: Vec<_> = (0 .. max as u32 + 1)
+              .filter(|&i| !self.hir_ids_seen.contains_key(&ItemLocalId(i)))
               .collect();
 
             // Try to map those to something more useful