To allow these braced macro invocation, this PR removes the optional expression from `ast::Block` and instead uses a `StmtKind::Expr` at the end of the statement list.
Currently, braced macro invocations in blocks can expand into statements (and items) except when they are last in a block, in which case they can only expand into expressions.
For example,
```rust
macro_rules! make_stmt {
() => { let x = 0; }
}
fn f() {
make_stmt! {} //< This is OK...
let x = 0; //< ... unless this line is commented out.
}
```
Fixes #34418.
}
fn lower_block(&mut self, b: &Block) -> P<hir::Block> {
+ let mut stmts = Vec::new();
+ let mut expr = None;
+
+ if let Some((last, rest)) = b.stmts.split_last() {
+ stmts = rest.iter().map(|s| self.lower_stmt(s)).collect::<Vec<_>>();
+ let last = self.lower_stmt(last);
+ if let hir::StmtExpr(e, _) = last.node {
+ expr = Some(e);
+ } else {
+ stmts.push(last);
+ }
+ }
+
P(hir::Block {
id: b.id,
- stmts: b.stmts.iter().map(|s| self.lower_stmt(s)).collect(),
- expr: b.expr.as_ref().map(|ref x| self.lower_expr(x)),
+ stmts: stmts.into(),
+ expr: expr,
rules: self.lower_block_check_mode(&b.rules),
span: b.span,
})
}
pub fn assign_node_ids(sess: &Session, krate: ast::Crate) -> ast::Crate {
+ use syntax::ptr::P;
+ use syntax::util::move_map::MoveMap;
+
struct NodeIdAssigner<'a> {
sess: &'a Session,
}
assert_eq!(old_id, ast::DUMMY_NODE_ID);
self.sess.next_node_id()
}
+
+ fn fold_block(&mut self, block: P<ast::Block>) -> P<ast::Block> {
+ block.map(|mut block| {
+ block.id = self.new_id(block.id);
+
+ let stmt = block.stmts.pop();
+ block.stmts = block.stmts.move_flat_map(|s| self.fold_stmt(s).into_iter());
+ if let Some(ast::Stmt { node: ast::StmtKind::Expr(expr), span, .. }) = stmt {
+ let expr = self.fold_expr(expr);
+ block.stmts.push(ast::Stmt {
+ id: expr.id,
+ node: ast::StmtKind::Expr(expr),
+ span: span,
+ });
+ } else if let Some(stmt) = stmt {
+ block.stmts.extend(self.fold_stmt(stmt));
+ }
+
+ block
+ })
+ }
}
let krate = time(sess.time_passes(),
fn fold_block(&mut self, b: P<ast::Block>) -> P<ast::Block> {
fn expr_to_block(rules: ast::BlockCheckMode, e: Option<P<ast::Expr>>) -> P<ast::Block> {
P(ast::Block {
- expr: e,
- stmts: vec![],
+ stmts: e.map(|e| ast::Stmt {
+ id: ast::DUMMY_NODE_ID,
+ span: e.span,
+ node: ast::StmtKind::Expr(e),
+ }).into_iter().collect(),
rules: rules,
id: ast::DUMMY_NODE_ID,
span: syntax_pos::DUMMY_SP,
pub struct Block {
/// Statements in a block
pub stmts: Vec<Stmt>,
- /// An expression at the end of the block
- /// without a semicolon, if any
- pub expr: Option<P<Expr>>,
pub id: NodeId,
/// Distinguishes between `unsafe { ... }` and `{ ... }`
pub rules: BlockCheckMode,
/// An item definition.
Item(P<Item>),
- /// Expr without trailing semi-colon (must have unit type).
+ /// Expr without trailing semi-colon.
Expr(P<Expr>),
Semi(P<Expr>),
// statements
fn stmt_expr(&self, expr: P<ast::Expr>) -> ast::Stmt;
+ fn stmt_semi(&self, expr: P<ast::Expr>) -> ast::Stmt;
fn stmt_let(&self, sp: Span, mutbl: bool, ident: ast::Ident, ex: P<ast::Expr>) -> ast::Stmt;
fn stmt_let_typed(&self,
sp: Span,
fn stmt_item(&self, sp: Span, item: P<ast::Item>) -> ast::Stmt;
// blocks
- fn block(&self, span: Span, stmts: Vec<ast::Stmt>,
- expr: Option<P<ast::Expr>>) -> P<ast::Block>;
+ fn block(&self, span: Span, stmts: Vec<ast::Stmt>) -> P<ast::Block>;
fn block_expr(&self, expr: P<ast::Expr>) -> P<ast::Block>;
- fn block_all(&self, span: Span,
- stmts: Vec<ast::Stmt>,
- expr: Option<P<ast::Expr>>) -> P<ast::Block>;
// expressions
fn expr(&self, span: Span, node: ast::ExprKind) -> P<ast::Expr>;
}
fn stmt_expr(&self, expr: P<ast::Expr>) -> ast::Stmt {
+ ast::Stmt {
+ id: ast::DUMMY_NODE_ID,
+ span: expr.span,
+ node: ast::StmtKind::Expr(expr),
+ }
+ }
+
+ fn stmt_semi(&self, expr: P<ast::Expr>) -> ast::Stmt {
ast::Stmt {
id: ast::DUMMY_NODE_ID,
span: expr.span,
})
}
- fn block(&self, span: Span, stmts: Vec<ast::Stmt>,
- expr: Option<P<Expr>>) -> P<ast::Block> {
- self.block_all(span, stmts, expr)
- }
-
fn stmt_item(&self, sp: Span, item: P<ast::Item>) -> ast::Stmt {
ast::Stmt {
id: ast::DUMMY_NODE_ID,
}
fn block_expr(&self, expr: P<ast::Expr>) -> P<ast::Block> {
- self.block_all(expr.span, Vec::new(), Some(expr))
- }
- fn block_all(&self,
- span: Span,
- stmts: Vec<ast::Stmt>,
- expr: Option<P<ast::Expr>>) -> P<ast::Block> {
- P(ast::Block {
- stmts: stmts,
- expr: expr,
- id: ast::DUMMY_NODE_ID,
- rules: BlockCheckMode::Default,
- span: span,
- })
+ self.block(expr.span, vec![ast::Stmt {
+ id: ast::DUMMY_NODE_ID,
+ span: expr.span,
+ node: ast::StmtKind::Expr(expr),
+ }])
+ }
+ fn block(&self, span: Span, stmts: Vec<ast::Stmt>) -> P<ast::Block> {
+ P(ast::Block {
+ stmts: stmts,
+ id: ast::DUMMY_NODE_ID,
+ rules: BlockCheckMode::Default,
+ span: span,
+ })
}
fn expr(&self, span: Span, node: ast::ExprKind) -> P<ast::Expr> {
ids: Vec<ast::Ident>,
stmts: Vec<ast::Stmt>)
-> P<ast::Expr> {
- self.lambda(span, ids, self.block(span, stmts, None))
+ self.lambda(span, ids, self.block(span, stmts))
}
fn lambda_stmts_0(&self, span: Span, stmts: Vec<ast::Stmt>) -> P<ast::Expr> {
- self.lambda0(span, self.block(span, stmts, None))
+ self.lambda0(span, self.block(span, stmts))
}
fn lambda_stmts_1(&self, span: Span, stmts: Vec<ast::Stmt>,
ident: ast::Ident) -> P<ast::Expr> {
- self.lambda1(span, self.block(span, stmts, None), ident)
+ self.lambda1(span, self.block(span, stmts), ident)
}
fn arg(&self, span: Span, ident: ast::Ident, ty: P<ast::Ty>) -> ast::Arg {
// expand the elements of a block.
pub fn expand_block_elts(b: P<Block>, fld: &mut MacroExpander) -> P<Block> {
- b.map(|Block {id, stmts, expr, rules, span}| {
+ b.map(|Block {id, stmts, rules, span}| {
let new_stmts = stmts.into_iter().flat_map(|x| {
// perform pending renames and expand macros in the statement
fld.fold_stmt(x).into_iter()
}).collect();
- let new_expr = expr.map(|x| {
- let expr = {
- let pending_renames = &mut fld.cx.syntax_env.info().pending_renames;
- let mut rename_fld = IdentRenamer{renames:pending_renames};
- rename_fld.fold_expr(x)
- };
- fld.fold_expr(expr)
- });
Block {
id: fld.new_id(id),
stmts: new_stmts,
- expr: new_expr,
rules: rules,
span: span
}
let (cx_expr, tts) = parse_arguments_to_quote(cx, tts);
let mut vector = mk_stmts_let(cx, sp);
vector.extend(statements_mk_tts(cx, &tts[..], true));
- let block = cx.expr_block(
- cx.block_all(sp,
- vector,
- Some(cx.expr_ident(sp, id_ext("tt")))));
+ vector.push(cx.stmt_expr(cx.expr_ident(sp, id_ext("tt"))));
+ let block = cx.expr_block(cx.block(sp, vector));
let expanded = expand_wrapper(cx, sp, cx_expr, block, &[&["syntax", "ext", "quote", "rt"]]);
base::MacEager::expr(expanded)
let stmt_let_tt = cx.stmt_let(sp, true, id_ext("tt"), cx.expr_vec_ng(sp));
let mut tts_stmts = vec![stmt_let_tt];
tts_stmts.extend(statements_mk_tts(cx, &seq.tts[..], matcher));
- let e_tts = cx.expr_block(cx.block(sp, tts_stmts,
- Some(cx.expr_ident(sp, id_ext("tt")))));
+ tts_stmts.push(cx.stmt_expr(cx.expr_ident(sp, id_ext("tt"))));
+ let e_tts = cx.expr_block(cx.block(sp, tts_stmts));
+
let e_separator = match seq.separator {
Some(ref sep) => cx.expr_some(sp, expr_mk_token(cx, sp, sep)),
None => cx.expr_none(sp),
let mut vector = mk_stmts_let(cx, sp);
vector.extend(statements_mk_tts(cx, &tts[..], false));
- let block = cx.expr_block(
- cx.block_all(sp,
- vector,
- Some(cx.expr_ident(sp, id_ext("tt")))));
+ vector.push(cx.stmt_expr(cx.expr_ident(sp, id_ext("tt"))));
+ let block = cx.expr_block(cx.block(sp, vector));
(cx_expr, block)
}
let cx_expr_borrow = cx.expr_addr_of(sp, cx.expr_deref(sp, cx_expr));
let stmt_let_ext_cx = cx.stmt_let(sp, false, id_ext("ext_cx"), cx_expr_borrow);
- let stmts = imports.iter().map(|path| {
+ let mut stmts = imports.iter().map(|path| {
// make item: `use ...;`
let path = path.iter().map(|s| s.to_string()).collect();
cx.stmt_item(sp, cx.item_use_glob(sp, ast::Visibility::Inherited, ids_ext(path)))
- }).chain(Some(stmt_let_ext_cx)).collect();
+ }).chain(Some(stmt_let_ext_cx)).collect::<Vec<_>>();
+ stmts.push(cx.stmt_expr(expr));
- cx.expr_block(cx.block_all(sp, stmts, Some(expr)))
+ cx.expr_block(cx.block(sp, stmts))
}
fn expand_parse_call(cx: &ExtCtxt,
}
pub fn noop_fold_block<T: Folder>(b: P<Block>, folder: &mut T) -> P<Block> {
- b.map(|Block {id, stmts, expr, rules, span}| Block {
+ b.map(|Block {id, stmts, rules, span}| Block {
id: folder.new_id(id),
stmts: stmts.move_flat_map(|s| folder.fold_stmt(s).into_iter()),
- expr: expr.and_then(|x| folder.fold_opt_expr(x)),
rules: rules,
span: folder.new_span(span),
})
attrs: ThinVec::new()})),
id: ast::DUMMY_NODE_ID,
span: sp(17,19)}),
- expr: None,
id: ast::DUMMY_NODE_ID,
rules: ast::BlockCheckMode::Default, // no idea
span: sp(15,21),
let body_expr = self.parse_expr()?;
P(ast::Block {
id: ast::DUMMY_NODE_ID,
- stmts: vec![],
span: body_expr.span,
- expr: Some(body_expr),
+ stmts: vec![Stmt {
+ span: body_expr.span,
+ node: StmtKind::Expr(body_expr),
+ id: ast::DUMMY_NODE_ID,
+ }],
rules: BlockCheckMode::Default,
})
}
/// Precondition: already parsed the '{'.
fn parse_block_tail(&mut self, lo: BytePos, s: BlockCheckMode) -> PResult<'a, P<Block>> {
let mut stmts = vec![];
- let mut expr = None;
while !self.eat(&token::CloseDelim(token::Brace)) {
let Stmt {node, span, ..} = if let Some(s) = self.parse_stmt_() {
match node {
StmtKind::Expr(e) => {
- self.handle_expression_like_statement(e, span, &mut stmts, &mut expr)?;
+ self.handle_expression_like_statement(e, span, &mut stmts)?;
}
StmtKind::Mac(mac) => {
- self.handle_macro_in_block(mac.unwrap(), span, &mut stmts, &mut expr)?;
+ self.handle_macro_in_block(mac.unwrap(), span, &mut stmts)?;
}
_ => { // all other kinds of statements:
let mut hi = span.hi;
Ok(P(ast::Block {
stmts: stmts,
- expr: expr,
id: ast::DUMMY_NODE_ID,
rules: s,
span: mk_sp(lo, self.last_span.hi),
fn handle_macro_in_block(&mut self,
(mac, style, attrs): (ast::Mac, MacStmtStyle, ThinVec<Attribute>),
span: Span,
- stmts: &mut Vec<Stmt>,
- last_block_expr: &mut Option<P<Expr>>)
+ stmts: &mut Vec<Stmt>)
-> PResult<'a, ()> {
if style == MacStmtStyle::NoBraces {
// statement macro without braces; might be an
let lo = e.span.lo;
let e = self.parse_dot_or_call_expr_with(e, lo, attrs)?;
let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
- self.handle_expression_like_statement(e, span, stmts, last_block_expr)?;
+ self.handle_expression_like_statement(e, span, stmts)?;
}
}
} else {
});
self.bump();
}
- token::CloseDelim(token::Brace) => {
- // if a block ends in `m!(arg)` without
- // a `;`, it must be an expr
- *last_block_expr = Some(self.mk_mac_expr(span.lo, span.hi, mac.node, attrs));
- }
_ => {
stmts.push(Stmt {
id: ast::DUMMY_NODE_ID,
fn handle_expression_like_statement(&mut self,
e: P<Expr>,
span: Span,
- stmts: &mut Vec<Stmt>,
- last_block_expr: &mut Option<P<Expr>>)
+ stmts: &mut Vec<Stmt>)
-> PResult<'a, ()> {
// expression without semicolon
if classify::expr_requires_semi_to_be_stmt(&e) {
span: span_with_semi,
});
}
- token::CloseDelim(token::Brace) => *last_block_expr = Some(e),
_ => {
stmts.push(Stmt {
id: ast::DUMMY_NODE_ID,
try!(self.word_space("="));
try!(self.print_expr(&init));
}
+ try!(word(&mut self.s, ";"));
self.end()?;
}
ast::StmtKind::Item(ref item) => self.print_item(&item)?,
ast::StmtKind::Expr(ref expr) => {
try!(self.space_if_not_bol());
try!(self.print_expr_outer_attr_style(&expr, false));
+ if parse::classify::expr_requires_semi_to_be_stmt(expr) {
+ try!(word(&mut self.s, ";"));
+ }
}
ast::StmtKind::Semi(ref expr) => {
try!(self.space_if_not_bol());
}
}
}
- if parse::classify::stmt_ends_with_semi(&st.node) {
- try!(word(&mut self.s, ";"));
- }
self.maybe_print_trailing_comment(st.span, None)
}
try!(self.print_inner_attributes(attrs));
- for st in &blk.stmts {
- try!(self.print_stmt(st));
- }
- match blk.expr {
- Some(ref expr) => {
- try!(self.space_if_not_bol());
- try!(self.print_expr_outer_attr_style(&expr, false));
- try!(self.maybe_print_trailing_comment(expr.span, Some(blk.span.hi)));
+ for (i, st) in blk.stmts.iter().enumerate() {
+ match st.node {
+ ast::StmtKind::Expr(ref expr) if i == blk.stmts.len() - 1 => {
+ try!(self.space_if_not_bol());
+ try!(self.print_expr_outer_attr_style(&expr, false));
+ try!(self.maybe_print_trailing_comment(expr.span, Some(blk.span.hi)));
+ }
+ _ => try!(self.print_stmt(st)),
}
- _ => ()
}
+
try!(self.bclose_maybe_open(blk.span, indented, close_box));
self.ann.post(self, NodeBlock(blk))
}
_ => false
};
- if !default_return || !body.stmts.is_empty() || body.expr.is_none() {
- try!(self.print_block_unclosed(&body));
- } else {
- // we extract the block, so as not to create another set of boxes
- let i_expr = body.expr.as_ref().unwrap();
- match i_expr.node {
- ast::ExprKind::Block(ref blk) => {
+ match body.stmts.last().map(|stmt| &stmt.node) {
+ Some(&ast::StmtKind::Expr(ref i_expr)) if default_return &&
+ body.stmts.len() == 1 => {
+ // we extract the block, so as not to create another set of boxes
+ if let ast::ExprKind::Block(ref blk) = i_expr.node {
try!(self.print_block_unclosed_with_attrs(&blk, &i_expr.attrs));
- }
- _ => {
+ } else {
// this is a bare expression
try!(self.print_expr(&i_expr));
try!(self.end()); // need to close a box
}
}
+ _ => try!(self.print_block_unclosed(&body)),
}
+
// a box will be closed by print_expr, but we didn't want an overall
// wrapper so we closed the corresponding opening. so create an
// empty box to satisfy the close.
let main_attr = ecx.attribute(sp, main_meta);
// pub fn main() { ... }
let main_ret_ty = ecx.ty(sp, ast::TyKind::Tup(vec![]));
- let main_body = ecx.block_all(sp, vec![call_test_main], None);
+ let main_body = ecx.block(sp, vec![call_test_main]);
let main = ast::ItemKind::Fn(ecx.fn_decl(vec![], main_ret_ty),
ast::Unsafety::Normal,
ast::Constness::NotConst,
pub fn walk_block<V: Visitor>(visitor: &mut V, block: &Block) {
walk_list!(visitor, visit_stmt, &block.stmts);
- walk_list!(visitor, visit_expr, &block.expr);
}
pub fn walk_stmt<V: Visitor>(visitor: &mut V, statement: &Stmt) {
match mode {
Mode::Shallow => {
- cx.expr_block(cx.block(trait_span,
- all_fields.iter()
- .map(subcall)
- .map(|e| cx.stmt_expr(e))
- .collect(),
- Some(cx.expr_deref(trait_span, cx.expr_self(trait_span)))))
+ let mut stmts: Vec<_> =
+ all_fields.iter().map(subcall).map(|e| cx.stmt_expr(e)).collect();
+ stmts.push(cx.stmt_expr(cx.expr_deref(trait_span, cx.expr_self(trait_span))));
+ cx.expr_block(cx.block(trait_span, stmts))
}
Mode::Deep => {
match *vdata {
// create `a.<method>(); b.<method>(); c.<method>(); ...`
// (where method is `assert_receiver_is_total_eq`)
let stmts = exprs.into_iter().map(|e| cx.stmt_expr(e)).collect();
- let block = cx.block(span, stmts, None);
+ let block = cx.block(span, stmts);
cx.expr_block(block)
},
Box::new(|cx, sp, _, _| {
let fmt = substr.nonself_args[0].clone();
- let stmts = match *substr.fields {
+ let mut stmts = match *substr.fields {
Struct(_, ref fields) | EnumMatching(_, _, ref fields) => {
let mut stmts = vec![];
if !is_struct {
token::str_to_ident("finish"),
vec![]);
- let block = cx.block(span, stmts, Some(expr));
+ stmts.push(cx.stmt_expr(expr));
+ let block = cx.block(span, stmts);
cx.expr_block(block)
}
cx.expr_str(trait_span, substr.type_ident.name.as_str()),
blk
));
- cx.expr_block(cx.block(trait_span, vec!(me), Some(ret)))
+ cx.expr_block(cx.block(trait_span, vec![me, cx.stmt_expr(ret)]))
}
_ => cx.bug("expected Struct or EnumMatching in derive(Encodable)")
// }
let all_match = cx.expr_match(sp, match_arg, match_arms);
let arm_expr = cx.expr_if(sp, discriminant_test, all_match, Some(arm_expr));
- cx.expr_block(
- cx.block_all(sp, index_let_stmts, Some(arm_expr)))
+ index_let_stmts.push(cx.stmt_expr(arm_expr));
+ cx.expr_block(cx.block(sp, index_let_stmts))
} else if variants.is_empty() {
// As an additional wrinkle, For a zero-variant enum A,
// currently the compiler
stmts.push(call_hash(span, self_.clone()));
}
- cx.expr_block(cx.block(trait_span, stmts, None))
+ cx.expr_block(cx.block(trait_span, stmts))
}
let call = cx.expr_call_global(span, path, args);
cx.expr_block(P(ast::Block {
- stmts: vec![],
- expr: Some(call),
+ stmts: vec![cx.stmt_expr(call)],
id: ast::DUMMY_NODE_ID,
rules: ast::BlockCheckMode::Unsafe(ast::CompilerGenerated),
span: span }))
};
// Wrap the declaration in a block so that it forms a single expression.
- ecx.expr_block(ecx.block(sp, vec![stmt], Some(ecx.expr_ident(sp, name))))
+ ecx.expr_block(ecx.block(sp, vec![stmt, ecx.stmt_expr(ecx.expr_ident(sp, name))]))
}
/// Actually builds the expression which the iformat! block will be expanded
--- /dev/null
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(rustc_attrs)]
+#![allow(unused)]
+
+macro_rules! make_item {
+ () => { fn f() {} }
+}
+
+macro_rules! make_stmt {
+ () => { let x = 0; }
+}
+
+fn f() {
+ make_item! {}
+}
+
+fn g() {
+ make_stmt! {}
+}
+
+#[rustc_error]
+fn main() {} //~ ERROR compilation successful
projects / rust.git / commitdiff