Cleanup dead code in hir::map::blocks.

Author: cjgillot

compiler/rustc_middle/src/hir/map/blocks.rs

@@ -11,12 +11,9 @@
 //! nested within a uniquely determined `FnLike`), and users can ask
 //! for the `Code` associated with a particular NodeId.
 
-use crate::hir::map::Map;
 use rustc_hir as hir;
 use rustc_hir::intravisit::FnKind;
-use rustc_hir::{Expr, FnDecl, Node};
-use rustc_span::symbol::Ident;
-use rustc_span::Span;
+use rustc_hir::Node;
 
 /// An FnLikeNode is a Node that is like a fn, in that it has a decl
 /// and a body (as well as a NodeId, a span, etc).
@@ -33,139 +30,21 @@ pub struct FnLikeNode<'a> {
     node: Node<'a>,
 }
 
-/// MaybeFnLike wraps a method that indicates if an object
-/// corresponds to some FnLikeNode.
-trait MaybeFnLike {
-    fn is_fn_like(&self) -> bool;
-}
-
-impl MaybeFnLike for hir::Item<'_> {
-    fn is_fn_like(&self) -> bool {
-        matches!(self.kind, hir::ItemKind::Fn(..))
-    }
-}
-
-impl MaybeFnLike for hir::ImplItem<'_> {
-    fn is_fn_like(&self) -> bool {
-        matches!(self.kind, hir::ImplItemKind::Fn(..))
-    }
-}
-
-impl MaybeFnLike for hir::TraitItem<'_> {
-    fn is_fn_like(&self) -> bool {
-        matches!(self.kind, hir::TraitItemKind::Fn(_, hir::TraitFn::Provided(_)))
-    }
-}
-
-impl MaybeFnLike for hir::Expr<'_> {
-    fn is_fn_like(&self) -> bool {
-        matches!(self.kind, hir::ExprKind::Closure(..))
-    }
-}
-
-/// Carries either an FnLikeNode or an Expr, as these are the two
-/// constructs that correspond to "code" (as in, something from which
-/// we can construct a control-flow graph).
-#[derive(Copy, Clone)]
-pub enum Code<'a> {
-    FnLike(FnLikeNode<'a>),
-    Expr(&'a Expr<'a>),
-}
-
-impl<'a> Code<'a> {
-    pub fn id(&self) -> hir::HirId {
-        match *self {
-            Code::FnLike(node) => node.id(),
-            Code::Expr(block) => block.hir_id,
-        }
-    }
-
-    /// Attempts to construct a Code from presumed FnLike or Expr node input.
-    pub fn from_node(map: &Map<'a>, id: hir::HirId) -> Option<Code<'a>> {
-        match map.get(id) {
-            Node::Block(_) => {
-                //  Use the parent, hopefully an expression node.
-                Code::from_node(map, map.get_parent_node(id))
-            }
-            Node::Expr(expr) => Some(Code::Expr(expr)),
-            node => FnLikeNode::from_node(node).map(Code::FnLike),
-        }
-    }
-}
-
-/// These are all the components one can extract from a fn item for
-/// use when implementing FnLikeNode operations.
-struct ItemFnParts<'a> {
-    ident: Ident,
-    decl: &'a hir::FnDecl<'a>,
-    header: hir::FnHeader,
-    vis: &'a hir::Visibility<'a>,
-    generics: &'a hir::Generics<'a>,
-    body: hir::BodyId,
-    id: hir::HirId,
-    span: Span,
-}
-
-/// These are all the components one can extract from a closure expr
-/// for use when implementing FnLikeNode operations.
-struct ClosureParts<'a> {
-    decl: &'a FnDecl<'a>,
-    body: hir::BodyId,
-    id: hir::HirId,
-    span: Span,
-}
-
-impl<'a> ClosureParts<'a> {
-    fn new(d: &'a FnDecl<'a>, b: hir::BodyId, id: hir::HirId, s: Span) -> Self {
-        ClosureParts { decl: d, body: b, id, span: s }
-    }
-}
-
 impl<'a> FnLikeNode<'a> {
     /// Attempts to construct a FnLikeNode from presumed FnLike node input.
     pub fn from_node(node: Node<'_>) -> Option<FnLikeNode<'_>> {
         let fn_like = match node {
-            Node::Item(item) => item.is_fn_like(),
-            Node::TraitItem(tm) => tm.is_fn_like(),
-            Node::ImplItem(it) => it.is_fn_like(),
-            Node::Expr(e) => e.is_fn_like(),
+            Node::Item(item) => matches!(item.kind, hir::ItemKind::Fn(..)),
+            Node::TraitItem(tm) => {
+                matches!(tm.kind, hir::TraitItemKind::Fn(_, hir::TraitFn::Provided(_)))
+            }
+            Node::ImplItem(it) => matches!(it.kind, hir::ImplItemKind::Fn(..)),
+            Node::Expr(e) => matches!(e.kind, hir::ExprKind::Closure(..)),
             _ => false,
         };
         fn_like.then_some(FnLikeNode { node })
     }
 
-    pub fn body(self) -> hir::BodyId {
-        self.handle(
-            |i: ItemFnParts<'a>| i.body,
-            |_, _, _: &'a hir::FnSig<'a>, _, body: hir::BodyId, _| body,
-            |c: ClosureParts<'a>| c.body,
-        )
-    }
-
-    pub fn decl(self) -> &'a FnDecl<'a> {
-        self.handle(
-            |i: ItemFnParts<'a>| &*i.decl,
-            |_, _, sig: &'a hir::FnSig<'a>, _, _, _| &sig.decl,
-            |c: ClosureParts<'a>| c.decl,
-        )
-    }
-
-    pub fn span(self) -> Span {
-        self.handle(
-            |i: ItemFnParts<'_>| i.span,
-            |_, _, _: &'a hir::FnSig<'a>, _, _, span| span,
-            |c: ClosureParts<'_>| c.span,
-        )
-    }
-
-    pub fn id(self) -> hir::HirId {
-        self.handle(
-            |i: ItemFnParts<'_>| i.id,
-            |id, _, _: &'a hir::FnSig<'a>, _, _, _| id,
-            |c: ClosureParts<'_>| c.id,
-        )
-    }
-
     pub fn constness(self) -> hir::Constness {
         self.kind().header().map_or(hir::Constness::NotConst, |header| header.constness)
     }
@@ -174,63 +53,26 @@ impl<'a> FnLikeNode<'a> {
         self.kind().header().map_or(hir::IsAsync::NotAsync, |header| header.asyncness)
     }
 
-    pub fn unsafety(self) -> hir::Unsafety {
-        self.kind().header().map_or(hir::Unsafety::Normal, |header| header.unsafety)
-    }
-
     pub fn kind(self) -> FnKind<'a> {
-        let item = |p: ItemFnParts<'a>| -> FnKind<'a> {
-            FnKind::ItemFn(p.ident, p.generics, p.header, p.vis)
-        };
-        let closure = |_: ClosureParts<'a>| FnKind::Closure;
-        let method =
-            |_, ident: Ident, sig: &'a hir::FnSig<'a>, vis, _, _| FnKind::Method(ident, sig, vis);
-        self.handle(item, method, closure)
-    }
-
-    fn handle<A, I, M, C>(self, item_fn: I, method: M, closure: C) -> A
-    where
-        I: FnOnce(ItemFnParts<'a>) -> A,
-        M: FnOnce(
-            hir::HirId,
-            Ident,
-            &'a hir::FnSig<'a>,
-            Option<&'a hir::Visibility<'a>>,
-            hir::BodyId,
-            Span,
-        ) -> A,
-        C: FnOnce(ClosureParts<'a>) -> A,
-    {
         match self.node {
             Node::Item(i) => match i.kind {
-                hir::ItemKind::Fn(ref sig, ref generics, block) => item_fn(ItemFnParts {
-                    id: i.hir_id(),
-                    ident: i.ident,
-                    decl: &sig.decl,
-                    body: block,
-                    vis: &i.vis,
-                    span: i.span,
-                    header: sig.header,
-                    generics,
-                }),
+                hir::ItemKind::Fn(ref sig, ref generics, _) => {
+                    FnKind::ItemFn(i.ident, generics, sig.header, &i.vis)
+                }
                 _ => bug!("item FnLikeNode that is not fn-like"),
             },
             Node::TraitItem(ti) => match ti.kind {
-                hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(body)) => {
-                    method(ti.hir_id(), ti.ident, sig, None, body, ti.span)
+                hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(_)) => {
+                    FnKind::Method(ti.ident, sig, None)
                 }
                 _ => bug!("trait method FnLikeNode that is not fn-like"),
             },
             Node::ImplItem(ii) => match ii.kind {
-                hir::ImplItemKind::Fn(ref sig, body) => {
-                    method(ii.hir_id(), ii.ident, sig, Some(&ii.vis), body, ii.span)
-                }
+                hir::ImplItemKind::Fn(ref sig, _) => FnKind::Method(ii.ident, sig, Some(&ii.vis)),
                 _ => bug!("impl method FnLikeNode that is not fn-like"),
             },
             Node::Expr(e) => match e.kind {
-                hir::ExprKind::Closure(_, ref decl, block, _fn_decl_span, _gen) => {
-                    closure(ClosureParts::new(&decl, block, e.hir_id, e.span))
-                }
+                hir::ExprKind::Closure(..) => FnKind::Closure,
                 _ => bug!("expr FnLikeNode that is not fn-like"),
             },
             _ => bug!("other FnLikeNode that is not fn-like"),