Remove redundant syntax::ast::Guard.

Author: Centril

src/librustc/hir/lowering.rs

@@ -1382,7 +1382,7 @@ impl<'a> LoweringContext<'a> {
  attrs: self.lower_attrs(&arm.attrs),
  pats: arm.pats.iter().map(|x| self.lower_pat(x)).collect(),
  guard: match arm.guard {
- Some(Guard::If(ref x)) => Some(hir::Guard::If(P(self.lower_expr(x)))),
+ Some(ref x) => Some(hir::Guard::If(P(self.lower_expr(x)))),
  _ => None,
  },
  body: P(self.lower_expr(&arm.body)),

src/librustc_resolve/lib.rs

@@ -3065,7 +3065,7 @@ impl<'a> Resolver<'a> {
  // This has to happen *after* we determine which pat_idents are variants.
  self.check_consistent_bindings(&arm.pats);
 
- if let Some(ast::Guard::If(ref expr)) = arm.guard {
+ if let Some(ref expr) = arm.guard {
  self.visit_expr(expr)
  }
  self.visit_expr(&arm.body);

src/librustc_save_analysis/dump_visitor.rs

@@ -1617,9 +1617,8 @@ impl<'l, 'tcx, 'll, O: DumpOutput + 'll> Visitor<'l> for DumpVisitor<'l, 'tcx, '
 
  fn visit_arm(&mut self, arm: &'l ast::Arm) {
  self.process_var_decl_multi(&arm.pats);
- match arm.guard {
- Some(ast::Guard::If(ref expr)) => self.visit_expr(expr),
- _ => {}
+ if let Some(expr) = &arm.guard {
+ self.visit_expr(expr);
  }
  self.visit_expr(&arm.body);
  }

src/libsyntax/ast.rs

@@ -893,16 +893,11 @@ pub struct Local {
 pub struct Arm {
  pub attrs: Vec<Attribute>,
  pub pats: Vec<P<Pat>>,
- pub guard: Option<Guard>,
+ pub guard: Option<P<Expr>>,
  pub body: P<Expr>,
  pub span: Span,
 }
 
-#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
-pub enum Guard {
- If(P<Expr>),
-}
-
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Field {
  pub ident: Ident,

src/libsyntax/mut_visit.rs

@@ -131,10 +131,6 @@ pub trait MutVisitor: Sized {
  noop_visit_arm(a, self);
  }
 
- fn visit_guard(&mut self, g: &mut Guard) {
- noop_visit_guard(g, self);
- }
-
  fn visit_pat(&mut self, p: &mut P<Pat>) {
  noop_visit_pat(p, self);
  }
@@ -389,17 +385,11 @@ pub fn noop_visit_arm<T: MutVisitor>(
 ) {
  visit_attrs(attrs, vis);
  visit_vec(pats, |pat| vis.visit_pat(pat));
- visit_opt(guard, |guard| vis.visit_guard(guard));
+ visit_opt(guard, |guard| vis.visit_expr(guard));
  vis.visit_expr(body);
  vis.visit_span(span);
 }
 
-pub fn noop_visit_guard<T: MutVisitor>(g: &mut Guard, vis: &mut T) {
- match g {
- Guard::If(e) => vis.visit_expr(e),
- }
-}
-
 pub fn noop_visit_ty_constraint<T: MutVisitor>(
  AssocTyConstraint { id, ident, kind, span }: &mut AssocTyConstraint,
  vis: &mut T

src/libsyntax/parse/parser.rs

@@ -3,7 +3,7 @@
 use crate::ast::{AngleBracketedArgs, ParenthesizedArgs, AttrStyle, BareFnTy};
 use crate::ast::{GenericBound, TraitBoundModifier};
 use crate::ast::Unsafety;
-use crate::ast::{Mod, AnonConst, Arg, Arm, Guard, Attribute, BindingMode, TraitItemKind};
+use crate::ast::{Mod, AnonConst, Arg, Arm, Attribute, BindingMode, TraitItemKind};
 use crate::ast::Block;
 use crate::ast::{BlockCheckMode, CaptureBy, Movability};
 use crate::ast::{Constness, Crate};
@@ -3413,7 +3413,7 @@ impl<'a> Parser<'a> {
  let lo = self.token.span;
  let pats = self.parse_pats()?;
  let guard = if self.eat_keyword(kw::If) {
- Some(Guard::If(self.parse_expr()?))
+ Some(self.parse_expr()?)
  } else {
  None
  };

src/libsyntax/print/pprust.rs

@@ -2663,14 +2663,10 @@ impl<'a> State<'a> {
  self.print_outer_attributes(&arm.attrs)?;
  self.print_pats(&arm.pats)?;
  self.s.space()?;
- if let Some(ref g) = arm.guard {
- match g {
- ast::Guard::If(ref e) => {
- self.word_space("if")?;
- self.print_expr(e)?;
- self.s.space()?;
- }
- }
+ if let Some(ref e) = arm.guard {
+ self.word_space("if")?;
+ self.print_expr(e)?;
+ self.s.space()?;
  }
  self.word_space("=>")?;
 

src/libsyntax/visit.rs

@@ -834,10 +834,8 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
 
 pub fn walk_arm<'a, V: Visitor<'a>>(visitor: &mut V, arm: &'a Arm) {
  walk_list!(visitor, visit_pat, &arm.pats);
- if let Some(ref g) = &arm.guard {
- match g {
- Guard::If(ref e) => visitor.visit_expr(e),
- }
+ if let Some(ref e) = &arm.guard {
+ visitor.visit_expr(e);
  }
  visitor.visit_expr(&arm.body);
  walk_list!(visitor, visit_attribute, &arm.attrs);