pub id: NodeId,
pub pat: P<Pat>,
pub ty: Option<P<Ty>>,
- /// Initializer expression to set the value, if any.
- pub init: Option<P<Expr>>,
+ pub kind: LocalKind,
pub span: Span,
pub attrs: AttrVec,
pub tokens: Option<LazyTokenStream>,
}
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub enum LocalKind {
+ /// Local declaration.
+ /// Example: `let x;`
+ Decl,
+ /// Local declaration with an initializer.
+ /// Example: `let x = y;`
+ Init(P<Expr>),
+ /// Local declaration with an initializer and an `else` clause.
+ /// Example: `let Some(x) = y else { return };`
+ InitElse(P<Expr>, P<Block>),
+}
+
+impl LocalKind {
+ pub fn init(&self) -> Option<&Expr> {
+ match self {
+ Self::Decl => None,
+ Self::Init(i) | Self::InitElse(i, _) => Some(i),
+ }
+ }
+
+ pub fn init_else_opt(&self) -> Option<(&Expr, Option<&Block>)> {
+ match self {
+ Self::Decl => None,
+ Self::Init(init) => Some((init, None)),
+ Self::InitElse(init, els) => Some((init, Some(els))),
+ }
+ }
+}
+
/// An arm of a 'match'.
///
/// E.g., `0..=10 => { println!("match!") }` as in
}
pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
- let Local { id, pat, ty, init, span, attrs, tokens } = local.deref_mut();
+ let Local { id, pat, ty, kind, span, attrs, tokens } = local.deref_mut();
vis.visit_id(id);
vis.visit_pat(pat);
visit_opt(ty, |ty| vis.visit_ty(ty));
- visit_opt(init, |init| vis.visit_expr(init));
+ match kind {
+ LocalKind::Decl => {}
+ LocalKind::Init(init) => {
+ vis.visit_expr(init);
+ }
+ LocalKind::InitElse(init, els) => {
+ vis.visit_expr(init);
+ vis.visit_block(els);
+ }
+ }
vis.visit_span(span);
visit_thin_attrs(attrs, vis);
visit_lazy_tts(tokens, vis);
}
visitor.visit_pat(&local.pat);
walk_list!(visitor, visit_ty, &local.ty);
- walk_list!(visitor, visit_expr, &local.init);
+ if let Some((init, els)) = local.kind.init_else_opt() {
+ visitor.visit_expr(init);
+ walk_list!(visitor, visit_block, els);
+ }
}
pub fn walk_label<'a, V: Visitor<'a>>(visitor: &mut V, label: &'a Label) {
.ty
.as_ref()
.map(|t| self.lower_ty(t, ImplTraitContext::Disallowed(ImplTraitPosition::Binding)));
- let init = l.init.as_ref().map(|e| self.lower_expr(e));
+ let init = l.kind.init().map(|init| self.lower_expr(init));
let hir_id = self.lower_node_id(l.id);
self.lower_attrs(hir_id, &l.attrs);
hir::Local {
self.ibox(INDENT_UNIT);
self.print_local_decl(loc);
self.end();
- if let Some(ref init) = loc.init {
+ if let Some((init, els)) = loc.kind.init_else_opt() {
self.nbsp();
self.word_space("=");
self.print_expr(init);
+ if let Some(els) = els {
+ self.cbox(INDENT_UNIT);
+ self.ibox(INDENT_UNIT);
+ self.s.word(" else ");
+ self.print_block(els);
+ }
}
self.s.word(";");
- self.end();
+ self.end(); // `let` ibox
}
ast::StmtKind::Item(ref item) => self.print_item(item),
ast::StmtKind::Expr(ref expr) => {
use crate::deriving::path_std;
use rustc_ast::ptr::P;
-use rustc_ast::{self as ast, Expr, MetaItem};
+use rustc_ast::{self as ast, Expr, LocalKind, MetaItem};
use rustc_expand::base::{Annotatable, ExtCtxt};
use rustc_span::symbol::{sym, Ident};
use rustc_span::{Span, DUMMY_SP};
let local = P(ast::Local {
pat: cx.pat_wild(sp),
ty: None,
- init: Some(expr),
id: ast::DUMMY_NODE_ID,
+ kind: LocalKind::Init(expr),
span: sp,
attrs: ast::AttrVec::new(),
tokens: None,
use rustc_ast::attr;
use rustc_ast::ptr::P;
-use rustc_ast::{self as ast, AttrVec, BlockCheckMode, Expr, PatKind, UnOp};
+use rustc_ast::{self as ast, AttrVec, BlockCheckMode, Expr, LocalKind, PatKind, UnOp};
use rustc_span::source_map::Spanned;
use rustc_span::symbol::{kw, sym, Ident, Symbol};
let local = P(ast::Local {
pat,
ty: None,
- init: Some(ex),
id: ast::DUMMY_NODE_ID,
+ kind: LocalKind::Init(ex),
span: sp,
attrs: AttrVec::new(),
tokens: None,
let local = P(ast::Local {
pat: self.pat_wild(span),
ty: Some(ty),
- init: None,
id: ast::DUMMY_NODE_ID,
+ kind: LocalKind::Decl,
span,
attrs: AttrVec::new(),
tokens: None,
fn check_stmt(&mut self, cx: &EarlyContext<'_>, s: &ast::Stmt) {
match s.kind {
StmtKind::Local(ref local) if Self::LINT_EXPR_IN_PATTERN_MATCHING_CTX => {
- if let Some(ref value) = local.init {
+ if let Some(value) = local.kind.init() {
self.check_unused_delims_expr(
cx,
&value,
use rustc_ast::ptr::P;
use rustc_ast::token::{self, TokenKind};
use rustc_ast::util::classify;
-use rustc_ast::AstLike;
-use rustc_ast::{AttrStyle, AttrVec, Attribute, MacCall, MacCallStmt, MacStmtStyle};
+use rustc_ast::{
+ AstLike, AttrStyle, AttrVec, Attribute, LocalKind, MacCall, MacCallStmt, MacStmtStyle,
+};
use rustc_ast::{Block, BlockCheckMode, Expr, ExprKind, Local, Stmt};
use rustc_ast::{StmtKind, DUMMY_NODE_ID};
use rustc_errors::{Applicability, PResult};
return Err(err);
}
};
+ let kind = match init {
+ None => LocalKind::Decl,
+ Some(init) => {
+ if self.eat_keyword(kw::Else) {
+ let els = self.parse_block()?;
+ LocalKind::InitElse(init, els)
+ } else {
+ LocalKind::Init(init)
+ }
+ }
+ };
let hi = if self.token == token::Semi { self.token.span } else { self.prev_token.span };
- Ok(P(ast::Local { ty, pat, init, id: DUMMY_NODE_ID, span: lo.to(hi), attrs, tokens: None }))
+ Ok(P(ast::Local { ty, pat, kind, id: DUMMY_NODE_ID, span: lo.to(hi), attrs, tokens: None }))
}
/// Parses the RHS of a local variable declaration (e.g., `= 14;`).
StmtKind::Expr(_) | StmtKind::MacCall(_) => {}
StmtKind::Local(ref mut local) if let Err(e) = self.expect_semi() => {
// We might be at the `,` in `let x = foo<bar, baz>;`. Try to recover.
- match &mut local.init {
- Some(ref mut expr) => {
- self.check_mistyped_turbofish_with_multiple_type_params(e, expr)?;
- // We found `foo<bar, baz>`, have we fully recovered?
- self.expect_semi()?;
- }
- None => return Err(e),
+ match &mut local.kind {
+ LocalKind::Init(expr) | LocalKind::InitElse(expr, _) => {
+ self.check_mistyped_turbofish_with_multiple_type_params(e, expr)?;
+ // We found `foo<bar, baz>`, have we fully recovered?
+ self.expect_semi()?;
+ }
+ LocalKind::Decl => return Err(e),
}
eat_semi = false;
}
_ => Some((
local.pat.span,
local.ty.as_ref().map(|ty| ty.span),
- local.init.as_ref().map(|init| init.span),
+ local.kind.init().map(|init| init.span),
)),
};
let original = replace(&mut self.diagnostic_metadata.current_let_binding, local_spans);
walk_list!(self, visit_ty, &local.ty);
// Resolve the initializer.
- walk_list!(self, visit_expr, &local.init);
+ if let Some((init, els)) = local.kind.init_else_opt() {
+ self.visit_expr(init);
+
+ // Resolve the `else` block
+ if let Some(els) = els {
+ self.visit_block(els);
+ }
+ }
// Resolve the pattern.
self.resolve_pattern_top(&local.pat, PatternSource::Let);