// statement without needing a semi-colon), then adding or removing braces
// can change whether it is treated as an expression or statement.
-// FIXME(topecongiro) Format async closures (#2813).
pub fn rewrite_closure(
capture: ast::CaptureBy,
+ asyncness: ast::IsAsync,
movability: ast::Movability,
fn_decl: &ast::FnDecl,
body: &ast::Expr,
) -> Option<String> {
debug!("rewrite_closure {:?}", body);
- let (prefix, extra_offset) =
- rewrite_closure_fn_decl(capture, movability, fn_decl, body, span, context, shape)?;
+ let (prefix, extra_offset) = rewrite_closure_fn_decl(
+ capture, asyncness, movability, fn_decl, body, span, context, shape,
+ )?;
// 1 = space between `|...|` and body.
let body_shape = shape.offset_left(extra_offset)?;
|| prefix.contains('\n')
}
+fn veto_block(e: &ast::Expr) -> bool {
+ match e.node {
+ ast::ExprKind::Call(..)
+ | ast::ExprKind::Binary(..)
+ | ast::ExprKind::Cast(..)
+ | ast::ExprKind::Type(..)
+ | ast::ExprKind::Assign(..)
+ | ast::ExprKind::AssignOp(..)
+ | ast::ExprKind::Field(..)
+ | ast::ExprKind::Index(..)
+ | ast::ExprKind::Range(..)
+ | ast::ExprKind::Try(..) => true,
+ _ => false,
+ }
+}
+
// Rewrite closure with a single expression wrapping its body with block.
fn rewrite_closure_with_block(
body: &ast::Expr,
shape: Shape,
) -> Option<String> {
let left_most = left_most_sub_expr(body);
- let veto_block = left_most != body && !classify::expr_requires_semi_to_be_stmt(left_most);
+ let veto_block = veto_block(body) && !classify::expr_requires_semi_to_be_stmt(left_most);
if veto_block {
return None;
}
} else {
Some(rw)
}
- })
- .map(|rw| format!("{} {}", prefix, rw))
+ }).map(|rw| format!("{} {}", prefix, rw))
}
// Rewrite closure whose body is block.
// Return type is (prefix, extra_offset)
fn rewrite_closure_fn_decl(
capture: ast::CaptureBy,
+ asyncness: ast::IsAsync,
movability: ast::Movability,
fn_decl: &ast::FnDecl,
body: &ast::Expr,
context: &RewriteContext,
shape: Shape,
) -> Option<(String, usize)> {
+ let is_async = if asyncness.is_async() { "async " } else { "" };
let mover = if capture == ast::CaptureBy::Value {
"move "
} else {
""
};
-
let immovable = if movability == ast::Movability::Static {
"static "
} else {
// 4 = "|| {".len(), which is overconservative when the closure consists of
// a single expression.
let nested_shape = shape
- .shrink_left(mover.len() + immovable.len())?
+ .shrink_left(is_async.len() + mover.len() + immovable.len())?
.sub_width(4)?;
// 1 = |
_ => arg_shape,
};
- let fmt = ListFormatting {
- tactic,
- separator: ",",
- trailing_separator: SeparatorTactic::Never,
- separator_place: SeparatorPlace::Back,
- shape: arg_shape,
- ends_with_newline: false,
- preserve_newline: true,
- nested: false,
- config: context.config,
- };
+ let fmt = ListFormatting::new(arg_shape, context.config)
+ .tactic(tactic)
+ .preserve_newline(true);
let list_str = write_list(&item_vec, &fmt)?;
- let mut prefix = format!("{}{}|{}|", immovable, mover, list_str);
+ let mut prefix = format!("{}{}{}|{}|", is_async, immovable, mover, list_str);
if !ret_str.is_empty() {
if prefix.contains('\n') {
expr: &ast::Expr,
shape: Shape,
) -> Option<String> {
- if let ast::ExprKind::Closure(capture, _, movability, ref fn_decl, ref body, _) = expr.node {
+ if let ast::ExprKind::Closure(capture, asyncness, movability, ref fn_decl, ref body, _) =
+ expr.node
+ {
let body = match body.node {
ast::ExprKind::Block(ref block, _)
if !is_unsafe_block(block)
_ => body,
};
let (prefix, extra_offset) = rewrite_closure_fn_decl(
- capture, movability, fn_decl, body, expr.span, context, shape,
+ capture, asyncness, movability, fn_decl, body, expr.span, context, shape,
)?;
// If the closure goes multi line before its body, do not overflow the closure.
if prefix.contains('\n') {
.map(|e| match e.node {
ast::ExprKind::Closure(..) => true,
_ => false,
- })
- .unwrap_or(false)
- })
- .count() > 1
+ }).unwrap_or(false)
+ }).count()
+ > 1
}
fn is_block_closure_forced(context: &RewriteContext, expr: &ast::Expr) -> bool {