| use crate::pp::Breaks::Inconsistent; |
| use crate::pprust::state::{AnnNode, PrintState, State, INDENT_UNIT}; |
| use ast::ForLoopKind; |
| use itertools::{Itertools, Position}; |
| use rustc_ast::ptr::P; |
| use rustc_ast::token; |
| use rustc_ast::util::classify; |
| use rustc_ast::util::literal::escape_byte_str_symbol; |
| use rustc_ast::util::parser::{self, AssocOp, Fixity}; |
| use rustc_ast::{self as ast, BlockCheckMode}; |
| use rustc_ast::{ |
| FormatAlignment, FormatArgPosition, FormatArgsPiece, FormatCount, FormatDebugHex, FormatSign, |
| FormatTrait, |
| }; |
| use std::fmt::Write; |
| |
| #[derive(Copy, Clone, Debug)] |
| pub(crate) struct FixupContext { |
| /// Print expression such that it can be parsed back as a statement |
| /// consisting of the original expression. |
| /// |
| /// The effect of this is for binary operators in statement position to set |
| /// `leftmost_subexpression_in_stmt` when printing their left-hand operand. |
| /// |
| /// ```ignore (illustrative) |
| /// (match x {}) - 1; // match needs parens when LHS of binary operator |
| /// |
| /// match x {}; // not when its own statement |
| /// ``` |
| pub stmt: bool, |
| |
| /// This is the difference between: |
| /// |
| /// ```ignore (illustrative) |
| /// (match x {}) - 1; // subexpression needs parens |
| /// |
| /// let _ = match x {} - 1; // no parens |
| /// ``` |
| /// |
| /// There are 3 distinguishable contexts in which `print_expr` might be |
| /// called with the expression `$match` as its argument, where `$match` |
| /// represents an expression of kind `ExprKind::Match`: |
| /// |
| /// - stmt=false leftmost_subexpression_in_stmt=false |
| /// |
| /// Example: `let _ = $match - 1;` |
| /// |
| /// No parentheses required. |
| /// |
| /// - stmt=false leftmost_subexpression_in_stmt=true |
| /// |
| /// Example: `$match - 1;` |
| /// |
| /// Must parenthesize `($match)`, otherwise parsing back the output as a |
| /// statement would terminate the statement after the closing brace of |
| /// the match, parsing `-1;` as a separate statement. |
| /// |
| /// - stmt=true leftmost_subexpression_in_stmt=false |
| /// |
| /// Example: `$match;` |
| /// |
| /// No parentheses required. |
| pub leftmost_subexpression_in_stmt: bool, |
| |
| /// This is the difference between: |
| /// |
| /// ```ignore (illustrative) |
| /// if let _ = (Struct {}) {} // needs parens |
| /// |
| /// match () { |
| /// () if let _ = Struct {} => {} // no parens |
| /// } |
| /// ``` |
| pub parenthesize_exterior_struct_lit: bool, |
| } |
| |
| /// The default amount of fixing is minimal fixing. Fixups should be turned on |
| /// in a targetted fashion where needed. |
| impl Default for FixupContext { |
| fn default() -> Self { |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: false, |
| parenthesize_exterior_struct_lit: false, |
| } |
| } |
| } |
| |
| impl<'a> State<'a> { |
| fn print_else(&mut self, els: Option<&ast::Expr>) { |
| if let Some(_else) = els { |
| match &_else.kind { |
| // Another `else if` block. |
| ast::ExprKind::If(i, then, e) => { |
| self.cbox(INDENT_UNIT - 1); |
| self.ibox(0); |
| self.word(" else if "); |
| self.print_expr_as_cond(i); |
| self.space(); |
| self.print_block(then); |
| self.print_else(e.as_deref()) |
| } |
| // Final `else` block. |
| ast::ExprKind::Block(b, _) => { |
| self.cbox(INDENT_UNIT - 1); |
| self.ibox(0); |
| self.word(" else "); |
| self.print_block(b) |
| } |
| // Constraints would be great here! |
| _ => { |
| panic!("print_if saw if with weird alternative"); |
| } |
| } |
| } |
| } |
| |
| fn print_if(&mut self, test: &ast::Expr, blk: &ast::Block, elseopt: Option<&ast::Expr>) { |
| self.head("if"); |
| self.print_expr_as_cond(test); |
| self.space(); |
| self.print_block(blk); |
| self.print_else(elseopt) |
| } |
| |
| fn print_call_post(&mut self, args: &[P<ast::Expr>]) { |
| self.popen(); |
| self.commasep_exprs(Inconsistent, args); |
| self.pclose() |
| } |
| |
| fn print_expr_maybe_paren(&mut self, expr: &ast::Expr, prec: i8, fixup: FixupContext) { |
| self.print_expr_cond_paren(expr, expr.precedence().order() < prec, fixup); |
| } |
| |
| /// Prints an expr using syntax that's acceptable in a condition position, such as the `cond` in |
| /// `if cond { ... }`. |
| fn print_expr_as_cond(&mut self, expr: &ast::Expr) { |
| let fixup = |
| FixupContext { parenthesize_exterior_struct_lit: true, ..FixupContext::default() }; |
| self.print_expr_cond_paren(expr, Self::cond_needs_par(expr), fixup) |
| } |
| |
| /// Does `expr` need parentheses when printed in a condition position? |
| /// |
| /// These cases need parens due to the parse error observed in #26461: `if return {}` |
| /// parses as the erroneous construct `if (return {})`, not `if (return) {}`. |
| fn cond_needs_par(expr: &ast::Expr) -> bool { |
| match expr.kind { |
| ast::ExprKind::Break(..) |
| | ast::ExprKind::Closure(..) |
| | ast::ExprKind::Ret(..) |
| | ast::ExprKind::Yeet(..) => true, |
| _ => parser::contains_exterior_struct_lit(expr), |
| } |
| } |
| |
| /// Prints `expr` or `(expr)` when `needs_par` holds. |
| pub(super) fn print_expr_cond_paren( |
| &mut self, |
| expr: &ast::Expr, |
| needs_par: bool, |
| mut fixup: FixupContext, |
| ) { |
| if needs_par { |
| self.popen(); |
| |
| // If we are surrounding the whole cond in parentheses, such as: |
| // |
| // if (return Struct {}) {} |
| // |
| // then there is no need for parenthesizing the individual struct |
| // expressions within. On the other hand if the whole cond is not |
| // parenthesized, then print_expr must parenthesize exterior struct |
| // literals. |
| // |
| // if x == (Struct {}) {} |
| // |
| fixup = FixupContext::default(); |
| } |
| |
| self.print_expr(expr, fixup); |
| |
| if needs_par { |
| self.pclose(); |
| } |
| } |
| |
| fn print_expr_vec(&mut self, exprs: &[P<ast::Expr>]) { |
| self.ibox(INDENT_UNIT); |
| self.word("["); |
| self.commasep_exprs(Inconsistent, exprs); |
| self.word("]"); |
| self.end(); |
| } |
| |
| pub(super) fn print_expr_anon_const( |
| &mut self, |
| expr: &ast::AnonConst, |
| attrs: &[ast::Attribute], |
| ) { |
| self.ibox(INDENT_UNIT); |
| self.word("const"); |
| self.nbsp(); |
| if let ast::ExprKind::Block(block, None) = &expr.value.kind { |
| self.cbox(0); |
| self.ibox(0); |
| self.print_block_with_attrs(block, attrs); |
| } else { |
| self.print_expr(&expr.value, FixupContext::default()); |
| } |
| self.end(); |
| } |
| |
| fn print_expr_repeat(&mut self, element: &ast::Expr, count: &ast::AnonConst) { |
| self.ibox(INDENT_UNIT); |
| self.word("["); |
| self.print_expr(element, FixupContext::default()); |
| self.word_space(";"); |
| self.print_expr(&count.value, FixupContext::default()); |
| self.word("]"); |
| self.end(); |
| } |
| |
| fn print_expr_struct( |
| &mut self, |
| qself: &Option<P<ast::QSelf>>, |
| path: &ast::Path, |
| fields: &[ast::ExprField], |
| rest: &ast::StructRest, |
| ) { |
| if let Some(qself) = qself { |
| self.print_qpath(path, qself, true); |
| } else { |
| self.print_path(path, true, 0); |
| } |
| self.nbsp(); |
| self.word("{"); |
| let has_rest = match rest { |
| ast::StructRest::Base(_) | ast::StructRest::Rest(_) => true, |
| ast::StructRest::None => false, |
| }; |
| if fields.is_empty() && !has_rest { |
| self.word("}"); |
| return; |
| } |
| self.cbox(0); |
| for (pos, field) in fields.iter().with_position() { |
| let is_first = matches!(pos, Position::First | Position::Only); |
| let is_last = matches!(pos, Position::Last | Position::Only); |
| self.maybe_print_comment(field.span.hi()); |
| self.print_outer_attributes(&field.attrs); |
| if is_first { |
| self.space_if_not_bol(); |
| } |
| if !field.is_shorthand { |
| self.print_ident(field.ident); |
| self.word_nbsp(":"); |
| } |
| self.print_expr(&field.expr, FixupContext::default()); |
| if !is_last || has_rest { |
| self.word_space(","); |
| } else { |
| self.trailing_comma_or_space(); |
| } |
| } |
| if has_rest { |
| if fields.is_empty() { |
| self.space(); |
| } |
| self.word(".."); |
| if let ast::StructRest::Base(expr) = rest { |
| self.print_expr(expr, FixupContext::default()); |
| } |
| self.space(); |
| } |
| self.offset(-INDENT_UNIT); |
| self.end(); |
| self.word("}"); |
| } |
| |
| fn print_expr_tup(&mut self, exprs: &[P<ast::Expr>]) { |
| self.popen(); |
| self.commasep_exprs(Inconsistent, exprs); |
| if exprs.len() == 1 { |
| self.word(","); |
| } |
| self.pclose() |
| } |
| |
| fn print_expr_call(&mut self, func: &ast::Expr, args: &[P<ast::Expr>], fixup: FixupContext) { |
| let prec = match func.kind { |
| ast::ExprKind::Field(..) => parser::PREC_FORCE_PAREN, |
| _ => parser::PREC_POSTFIX, |
| }; |
| |
| // Independent of parenthesization related to precedence, we must |
| // parenthesize `func` if this is a statement context in which without |
| // parentheses, a statement boundary would occur inside `func` or |
| // immediately after `func`. |
| // |
| // Suppose `func` represents `match () { _ => f }`. We must produce: |
| // |
| // (match () { _ => f })(); |
| // |
| // instead of: |
| // |
| // match () { _ => f } (); |
| // |
| // because the latter is valid syntax but with the incorrect meaning. |
| // It's a match-expression followed by tuple-expression, not a function |
| // call. |
| self.print_expr_maybe_paren( |
| func, |
| prec, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: fixup.stmt || fixup.leftmost_subexpression_in_stmt, |
| ..fixup |
| }, |
| ); |
| |
| self.print_call_post(args) |
| } |
| |
| fn print_expr_method_call( |
| &mut self, |
| segment: &ast::PathSegment, |
| receiver: &ast::Expr, |
| base_args: &[P<ast::Expr>], |
| fixup: FixupContext, |
| ) { |
| // Unlike in `print_expr_call`, no change to fixup here because |
| // statement boundaries never occur in front of a `.` (or `?`) token. |
| // |
| // match () { _ => f }.method(); |
| // |
| // Parenthesizing only for precedence and not with regard to statement |
| // boundaries, `$receiver.method()` can be parsed back as a statement |
| // containing an expression if and only if `$receiver` can be parsed as |
| // a statement containing an expression. |
| self.print_expr_maybe_paren(receiver, parser::PREC_POSTFIX, fixup); |
| |
| self.word("."); |
| self.print_ident(segment.ident); |
| if let Some(args) = &segment.args { |
| self.print_generic_args(args, true); |
| } |
| self.print_call_post(base_args) |
| } |
| |
| fn print_expr_binary( |
| &mut self, |
| op: ast::BinOp, |
| lhs: &ast::Expr, |
| rhs: &ast::Expr, |
| fixup: FixupContext, |
| ) { |
| let assoc_op = AssocOp::from_ast_binop(op.node); |
| let prec = assoc_op.precedence() as i8; |
| let fixity = assoc_op.fixity(); |
| |
| let (left_prec, right_prec) = match fixity { |
| Fixity::Left => (prec, prec + 1), |
| Fixity::Right => (prec + 1, prec), |
| Fixity::None => (prec + 1, prec + 1), |
| }; |
| |
| let left_prec = match (&lhs.kind, op.node) { |
| // These cases need parens: `x as i32 < y` has the parser thinking that `i32 < y` is |
| // the beginning of a path type. It starts trying to parse `x as (i32 < y ...` instead |
| // of `(x as i32) < ...`. We need to convince it _not_ to do that. |
| (&ast::ExprKind::Cast { .. }, ast::BinOpKind::Lt | ast::BinOpKind::Shl) => { |
| parser::PREC_FORCE_PAREN |
| } |
| // We are given `(let _ = a) OP b`. |
| // |
| // - When `OP <= LAnd` we should print `let _ = a OP b` to avoid redundant parens |
| // as the parser will interpret this as `(let _ = a) OP b`. |
| // |
| // - Otherwise, e.g. when we have `(let a = b) < c` in AST, |
| // parens are required since the parser would interpret `let a = b < c` as |
| // `let a = (b < c)`. To achieve this, we force parens. |
| (&ast::ExprKind::Let { .. }, _) if !parser::needs_par_as_let_scrutinee(prec) => { |
| parser::PREC_FORCE_PAREN |
| } |
| _ => left_prec, |
| }; |
| |
| self.print_expr_maybe_paren( |
| lhs, |
| left_prec, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: fixup.stmt || fixup.leftmost_subexpression_in_stmt, |
| ..fixup |
| }, |
| ); |
| |
| self.space(); |
| self.word_space(op.node.as_str()); |
| |
| self.print_expr_maybe_paren( |
| rhs, |
| right_prec, |
| FixupContext { stmt: false, leftmost_subexpression_in_stmt: false, ..fixup }, |
| ); |
| } |
| |
| fn print_expr_unary(&mut self, op: ast::UnOp, expr: &ast::Expr, fixup: FixupContext) { |
| self.word(op.as_str()); |
| self.print_expr_maybe_paren( |
| expr, |
| parser::PREC_PREFIX, |
| FixupContext { stmt: false, leftmost_subexpression_in_stmt: false, ..fixup }, |
| ); |
| } |
| |
| fn print_expr_addr_of( |
| &mut self, |
| kind: ast::BorrowKind, |
| mutability: ast::Mutability, |
| expr: &ast::Expr, |
| fixup: FixupContext, |
| ) { |
| self.word("&"); |
| match kind { |
| ast::BorrowKind::Ref => self.print_mutability(mutability, false), |
| ast::BorrowKind::Raw => { |
| self.word_nbsp("raw"); |
| self.print_mutability(mutability, true); |
| } |
| } |
| self.print_expr_maybe_paren( |
| expr, |
| parser::PREC_PREFIX, |
| FixupContext { stmt: false, leftmost_subexpression_in_stmt: false, ..fixup }, |
| ); |
| } |
| |
| pub(super) fn print_expr(&mut self, expr: &ast::Expr, fixup: FixupContext) { |
| self.print_expr_outer_attr_style(expr, true, fixup) |
| } |
| |
| pub(super) fn print_expr_outer_attr_style( |
| &mut self, |
| expr: &ast::Expr, |
| is_inline: bool, |
| mut fixup: FixupContext, |
| ) { |
| self.maybe_print_comment(expr.span.lo()); |
| |
| let attrs = &expr.attrs; |
| if is_inline { |
| self.print_outer_attributes_inline(attrs); |
| } else { |
| self.print_outer_attributes(attrs); |
| } |
| |
| self.ibox(INDENT_UNIT); |
| |
| // The Match subexpression in `match x {} - 1` must be parenthesized if |
| // it is the leftmost subexpression in a statement: |
| // |
| // (match x {}) - 1; |
| // |
| // But not otherwise: |
| // |
| // let _ = match x {} - 1; |
| // |
| // Same applies to a small set of other expression kinds which eagerly |
| // terminate a statement which opens with them. |
| let needs_par = |
| fixup.leftmost_subexpression_in_stmt && !classify::expr_requires_semi_to_be_stmt(expr); |
| if needs_par { |
| self.popen(); |
| fixup = FixupContext::default(); |
| } |
| |
| self.ann.pre(self, AnnNode::Expr(expr)); |
| |
| match &expr.kind { |
| ast::ExprKind::Array(exprs) => { |
| self.print_expr_vec(exprs); |
| } |
| ast::ExprKind::ConstBlock(anon_const) => { |
| self.print_expr_anon_const(anon_const, attrs); |
| } |
| ast::ExprKind::Repeat(element, count) => { |
| self.print_expr_repeat(element, count); |
| } |
| ast::ExprKind::Struct(se) => { |
| self.print_expr_struct(&se.qself, &se.path, &se.fields, &se.rest); |
| } |
| ast::ExprKind::Tup(exprs) => { |
| self.print_expr_tup(exprs); |
| } |
| ast::ExprKind::Call(func, args) => { |
| self.print_expr_call(func, args, fixup); |
| } |
| ast::ExprKind::MethodCall(box ast::MethodCall { seg, receiver, args, .. }) => { |
| self.print_expr_method_call(seg, receiver, args, fixup); |
| } |
| ast::ExprKind::Binary(op, lhs, rhs) => { |
| self.print_expr_binary(*op, lhs, rhs, fixup); |
| } |
| ast::ExprKind::Unary(op, expr) => { |
| self.print_expr_unary(*op, expr, fixup); |
| } |
| ast::ExprKind::AddrOf(k, m, expr) => { |
| self.print_expr_addr_of(*k, *m, expr, fixup); |
| } |
| ast::ExprKind::Lit(token_lit) => { |
| self.print_token_literal(*token_lit, expr.span); |
| } |
| ast::ExprKind::IncludedBytes(bytes) => { |
| let lit = token::Lit::new(token::ByteStr, escape_byte_str_symbol(bytes), None); |
| self.print_token_literal(lit, expr.span) |
| } |
| ast::ExprKind::Cast(expr, ty) => { |
| let prec = AssocOp::As.precedence() as i8; |
| self.print_expr_maybe_paren( |
| expr, |
| prec, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: fixup.stmt |
| || fixup.leftmost_subexpression_in_stmt, |
| ..fixup |
| }, |
| ); |
| self.space(); |
| self.word_space("as"); |
| self.print_type(ty); |
| } |
| ast::ExprKind::Type(expr, ty) => { |
| self.word("type_ascribe!("); |
| self.ibox(0); |
| self.print_expr(expr, FixupContext::default()); |
| |
| self.word(","); |
| self.space_if_not_bol(); |
| self.print_type(ty); |
| |
| self.end(); |
| self.word(")"); |
| } |
| ast::ExprKind::Let(pat, scrutinee, _, _) => { |
| self.print_let(pat, scrutinee, fixup); |
| } |
| ast::ExprKind::If(test, blk, elseopt) => self.print_if(test, blk, elseopt.as_deref()), |
| ast::ExprKind::While(test, blk, opt_label) => { |
| if let Some(label) = opt_label { |
| self.print_ident(label.ident); |
| self.word_space(":"); |
| } |
| self.cbox(0); |
| self.ibox(0); |
| self.word_nbsp("while"); |
| self.print_expr_as_cond(test); |
| self.space(); |
| self.print_block_with_attrs(blk, attrs); |
| } |
| ast::ExprKind::ForLoop { pat, iter, body, label, kind } => { |
| if let Some(label) = label { |
| self.print_ident(label.ident); |
| self.word_space(":"); |
| } |
| self.cbox(0); |
| self.ibox(0); |
| self.word_nbsp("for"); |
| if kind == &ForLoopKind::ForAwait { |
| self.word_nbsp("await"); |
| } |
| self.print_pat(pat); |
| self.space(); |
| self.word_space("in"); |
| self.print_expr_as_cond(iter); |
| self.space(); |
| self.print_block_with_attrs(body, attrs); |
| } |
| ast::ExprKind::Loop(blk, opt_label, _) => { |
| if let Some(label) = opt_label { |
| self.print_ident(label.ident); |
| self.word_space(":"); |
| } |
| self.cbox(0); |
| self.ibox(0); |
| self.word_nbsp("loop"); |
| self.print_block_with_attrs(blk, attrs); |
| } |
| ast::ExprKind::Match(expr, arms) => { |
| self.cbox(0); |
| self.ibox(0); |
| self.word_nbsp("match"); |
| self.print_expr_as_cond(expr); |
| self.space(); |
| self.bopen(); |
| self.print_inner_attributes_no_trailing_hardbreak(attrs); |
| for arm in arms { |
| self.print_arm(arm); |
| } |
| let empty = attrs.is_empty() && arms.is_empty(); |
| self.bclose(expr.span, empty); |
| } |
| ast::ExprKind::Closure(box ast::Closure { |
| binder, |
| capture_clause, |
| constness, |
| coroutine_kind, |
| movability, |
| fn_decl, |
| body, |
| fn_decl_span: _, |
| fn_arg_span: _, |
| }) => { |
| self.print_closure_binder(binder); |
| self.print_constness(*constness); |
| self.print_movability(*movability); |
| coroutine_kind.map(|coroutine_kind| self.print_coroutine_kind(coroutine_kind)); |
| self.print_capture_clause(*capture_clause); |
| |
| self.print_fn_params_and_ret(fn_decl, true); |
| self.space(); |
| self.print_expr(body, FixupContext::default()); |
| self.end(); // need to close a box |
| |
| // 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. |
| self.ibox(0); |
| } |
| ast::ExprKind::Block(blk, opt_label) => { |
| if let Some(label) = opt_label { |
| self.print_ident(label.ident); |
| self.word_space(":"); |
| } |
| // containing cbox, will be closed by print-block at } |
| self.cbox(0); |
| // head-box, will be closed by print-block after { |
| self.ibox(0); |
| self.print_block_with_attrs(blk, attrs); |
| } |
| ast::ExprKind::Gen(capture_clause, blk, kind) => { |
| self.word_nbsp(kind.modifier()); |
| self.print_capture_clause(*capture_clause); |
| // cbox/ibox in analogy to the `ExprKind::Block` arm above |
| self.cbox(0); |
| self.ibox(0); |
| self.print_block_with_attrs(blk, attrs); |
| } |
| ast::ExprKind::Await(expr, _) => { |
| // Same fixups as ExprKind::MethodCall. |
| self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX, fixup); |
| self.word(".await"); |
| } |
| ast::ExprKind::Assign(lhs, rhs, _) => { |
| // Same fixups as ExprKind::Binary. |
| let prec = AssocOp::Assign.precedence() as i8; |
| self.print_expr_maybe_paren( |
| lhs, |
| prec + 1, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: fixup.stmt |
| || fixup.leftmost_subexpression_in_stmt, |
| ..fixup |
| }, |
| ); |
| self.space(); |
| self.word_space("="); |
| self.print_expr_maybe_paren( |
| rhs, |
| prec, |
| FixupContext { stmt: false, leftmost_subexpression_in_stmt: false, ..fixup }, |
| ); |
| } |
| ast::ExprKind::AssignOp(op, lhs, rhs) => { |
| // Same fixups as ExprKind::Binary. |
| let prec = AssocOp::Assign.precedence() as i8; |
| self.print_expr_maybe_paren( |
| lhs, |
| prec + 1, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: fixup.stmt |
| || fixup.leftmost_subexpression_in_stmt, |
| ..fixup |
| }, |
| ); |
| self.space(); |
| self.word(op.node.as_str()); |
| self.word_space("="); |
| self.print_expr_maybe_paren( |
| rhs, |
| prec, |
| FixupContext { stmt: false, leftmost_subexpression_in_stmt: false, ..fixup }, |
| ); |
| } |
| ast::ExprKind::Field(expr, ident) => { |
| // Same fixups as ExprKind::MethodCall. |
| self.print_expr_maybe_paren(expr, parser::PREC_POSTFIX, fixup); |
| self.word("."); |
| self.print_ident(*ident); |
| } |
| ast::ExprKind::Index(expr, index, _) => { |
| // Same fixups as ExprKind::Call. |
| self.print_expr_maybe_paren( |
| expr, |
| parser::PREC_POSTFIX, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: fixup.stmt |
| || fixup.leftmost_subexpression_in_stmt, |
| ..fixup |
| }, |
| ); |
| self.word("["); |
| self.print_expr(index, FixupContext::default()); |
| self.word("]"); |
| } |
| ast::ExprKind::Range(start, end, limits) => { |
| // Special case for `Range`. `AssocOp` claims that `Range` has higher precedence |
| // than `Assign`, but `x .. x = x` gives a parse error instead of `x .. (x = x)`. |
| // Here we use a fake precedence value so that any child with lower precedence than |
| // a "normal" binop gets parenthesized. (`LOr` is the lowest-precedence binop.) |
| let fake_prec = AssocOp::LOr.precedence() as i8; |
| if let Some(e) = start { |
| self.print_expr_maybe_paren( |
| e, |
| fake_prec, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: fixup.stmt |
| || fixup.leftmost_subexpression_in_stmt, |
| ..fixup |
| }, |
| ); |
| } |
| match limits { |
| ast::RangeLimits::HalfOpen => self.word(".."), |
| ast::RangeLimits::Closed => self.word("..="), |
| } |
| if let Some(e) = end { |
| self.print_expr_maybe_paren( |
| e, |
| fake_prec, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: false, |
| ..fixup |
| }, |
| ); |
| } |
| } |
| ast::ExprKind::Underscore => self.word("_"), |
| ast::ExprKind::Path(None, path) => self.print_path(path, true, 0), |
| ast::ExprKind::Path(Some(qself), path) => self.print_qpath(path, qself, true), |
| ast::ExprKind::Break(opt_label, opt_expr) => { |
| self.word("break"); |
| if let Some(label) = opt_label { |
| self.space(); |
| self.print_ident(label.ident); |
| } |
| if let Some(expr) = opt_expr { |
| self.space(); |
| self.print_expr_maybe_paren( |
| expr, |
| parser::PREC_JUMP, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: false, |
| ..fixup |
| }, |
| ); |
| } |
| } |
| ast::ExprKind::Continue(opt_label) => { |
| self.word("continue"); |
| if let Some(label) = opt_label { |
| self.space(); |
| self.print_ident(label.ident); |
| } |
| } |
| ast::ExprKind::Ret(result) => { |
| self.word("return"); |
| if let Some(expr) = result { |
| self.word(" "); |
| self.print_expr_maybe_paren( |
| expr, |
| parser::PREC_JUMP, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: false, |
| ..fixup |
| }, |
| ); |
| } |
| } |
| ast::ExprKind::Yeet(result) => { |
| self.word("do"); |
| self.word(" "); |
| self.word("yeet"); |
| if let Some(expr) = result { |
| self.word(" "); |
| self.print_expr_maybe_paren( |
| expr, |
| parser::PREC_JUMP, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: false, |
| ..fixup |
| }, |
| ); |
| } |
| } |
| ast::ExprKind::Become(result) => { |
| self.word("become"); |
| self.word(" "); |
| self.print_expr_maybe_paren( |
| result, |
| parser::PREC_JUMP, |
| FixupContext { stmt: false, leftmost_subexpression_in_stmt: false, ..fixup }, |
| ); |
| } |
| ast::ExprKind::InlineAsm(a) => { |
| // FIXME: This should have its own syntax, distinct from a macro invocation. |
| self.word("asm!"); |
| self.print_inline_asm(a); |
| } |
| ast::ExprKind::FormatArgs(fmt) => { |
| // FIXME: This should have its own syntax, distinct from a macro invocation. |
| self.word("format_args!"); |
| self.popen(); |
| self.rbox(0, Inconsistent); |
| self.word(reconstruct_format_args_template_string(&fmt.template)); |
| for arg in fmt.arguments.all_args() { |
| self.word_space(","); |
| self.print_expr(&arg.expr, FixupContext::default()); |
| } |
| self.end(); |
| self.pclose(); |
| } |
| ast::ExprKind::OffsetOf(container, fields) => { |
| self.word("builtin # offset_of"); |
| self.popen(); |
| self.rbox(0, Inconsistent); |
| self.print_type(container); |
| self.word(","); |
| self.space(); |
| |
| if let Some((&first, rest)) = fields.split_first() { |
| self.print_ident(first); |
| |
| for &field in rest { |
| self.word("."); |
| self.print_ident(field); |
| } |
| } |
| self.pclose(); |
| self.end(); |
| } |
| ast::ExprKind::MacCall(m) => self.print_mac(m), |
| ast::ExprKind::Paren(e) => { |
| self.popen(); |
| self.print_expr(e, FixupContext::default()); |
| self.pclose(); |
| } |
| ast::ExprKind::Yield(e) => { |
| self.word("yield"); |
| |
| if let Some(expr) = e { |
| self.space(); |
| self.print_expr_maybe_paren( |
| expr, |
| parser::PREC_JUMP, |
| FixupContext { |
| stmt: false, |
| leftmost_subexpression_in_stmt: false, |
| ..fixup |
| }, |
| ); |
| } |
| } |
| ast::ExprKind::Try(e) => { |
| // Same fixups as ExprKind::MethodCall. |
| self.print_expr_maybe_paren(e, parser::PREC_POSTFIX, fixup); |
| self.word("?") |
| } |
| ast::ExprKind::TryBlock(blk) => { |
| self.cbox(0); |
| self.ibox(0); |
| self.word_nbsp("try"); |
| self.print_block_with_attrs(blk, attrs) |
| } |
| ast::ExprKind::Err(_) => { |
| self.popen(); |
| self.word("/*ERROR*/"); |
| self.pclose() |
| } |
| ast::ExprKind::Dummy => { |
| self.popen(); |
| self.word("/*DUMMY*/"); |
| self.pclose(); |
| } |
| } |
| |
| self.ann.post(self, AnnNode::Expr(expr)); |
| |
| if needs_par { |
| self.pclose(); |
| } |
| |
| self.end(); |
| } |
| |
| fn print_arm(&mut self, arm: &ast::Arm) { |
| // Note, I have no idea why this check is necessary, but here it is. |
| if arm.attrs.is_empty() { |
| self.space(); |
| } |
| self.cbox(INDENT_UNIT); |
| self.ibox(0); |
| self.maybe_print_comment(arm.pat.span.lo()); |
| self.print_outer_attributes(&arm.attrs); |
| self.print_pat(&arm.pat); |
| self.space(); |
| if let Some(e) = &arm.guard { |
| self.word_space("if"); |
| self.print_expr(e, FixupContext::default()); |
| self.space(); |
| } |
| |
| if let Some(body) = &arm.body { |
| self.word_space("=>"); |
| |
| match &body.kind { |
| ast::ExprKind::Block(blk, opt_label) => { |
| if let Some(label) = opt_label { |
| self.print_ident(label.ident); |
| self.word_space(":"); |
| } |
| |
| // The block will close the pattern's ibox. |
| self.print_block_unclosed_indent(blk); |
| |
| // If it is a user-provided unsafe block, print a comma after it. |
| if let BlockCheckMode::Unsafe(ast::UserProvided) = blk.rules { |
| self.word(","); |
| } |
| } |
| _ => { |
| self.end(); // Close the ibox for the pattern. |
| self.print_expr(body, FixupContext { stmt: true, ..FixupContext::default() }); |
| self.word(","); |
| } |
| } |
| } else { |
| self.word(","); |
| } |
| self.end(); // Close enclosing cbox. |
| } |
| |
| fn print_closure_binder(&mut self, binder: &ast::ClosureBinder) { |
| match binder { |
| ast::ClosureBinder::NotPresent => {} |
| ast::ClosureBinder::For { generic_params, .. } => { |
| self.print_formal_generic_params(generic_params) |
| } |
| } |
| } |
| |
| fn print_movability(&mut self, movability: ast::Movability) { |
| match movability { |
| ast::Movability::Static => self.word_space("static"), |
| ast::Movability::Movable => {} |
| } |
| } |
| |
| fn print_capture_clause(&mut self, capture_clause: ast::CaptureBy) { |
| match capture_clause { |
| ast::CaptureBy::Value { .. } => self.word_space("move"), |
| ast::CaptureBy::Ref => {} |
| } |
| } |
| } |
| |
| fn reconstruct_format_args_template_string(pieces: &[FormatArgsPiece]) -> String { |
| let mut template = "\"".to_string(); |
| for piece in pieces { |
| match piece { |
| FormatArgsPiece::Literal(s) => { |
| for c in s.as_str().chars() { |
| template.extend(c.escape_debug()); |
| if let '{' | '}' = c { |
| template.push(c); |
| } |
| } |
| } |
| FormatArgsPiece::Placeholder(p) => { |
| template.push('{'); |
| let (Ok(n) | Err(n)) = p.argument.index; |
| write!(template, "{n}").unwrap(); |
| if p.format_options != Default::default() || p.format_trait != FormatTrait::Display |
| { |
| template.push(':'); |
| } |
| if let Some(fill) = p.format_options.fill { |
| template.push(fill); |
| } |
| match p.format_options.alignment { |
| Some(FormatAlignment::Left) => template.push('<'), |
| Some(FormatAlignment::Right) => template.push('>'), |
| Some(FormatAlignment::Center) => template.push('^'), |
| None => {} |
| } |
| match p.format_options.sign { |
| Some(FormatSign::Plus) => template.push('+'), |
| Some(FormatSign::Minus) => template.push('-'), |
| None => {} |
| } |
| if p.format_options.alternate { |
| template.push('#'); |
| } |
| if p.format_options.zero_pad { |
| template.push('0'); |
| } |
| if let Some(width) = &p.format_options.width { |
| match width { |
| FormatCount::Literal(n) => write!(template, "{n}").unwrap(), |
| FormatCount::Argument(FormatArgPosition { |
| index: Ok(n) | Err(n), .. |
| }) => { |
| write!(template, "{n}$").unwrap(); |
| } |
| } |
| } |
| if let Some(precision) = &p.format_options.precision { |
| template.push('.'); |
| match precision { |
| FormatCount::Literal(n) => write!(template, "{n}").unwrap(), |
| FormatCount::Argument(FormatArgPosition { |
| index: Ok(n) | Err(n), .. |
| }) => { |
| write!(template, "{n}$").unwrap(); |
| } |
| } |
| } |
| match p.format_options.debug_hex { |
| Some(FormatDebugHex::Lower) => template.push('x'), |
| Some(FormatDebugHex::Upper) => template.push('X'), |
| None => {} |
| } |
| template.push_str(match p.format_trait { |
| FormatTrait::Display => "", |
| FormatTrait::Debug => "?", |
| FormatTrait::LowerExp => "e", |
| FormatTrait::UpperExp => "E", |
| FormatTrait::Octal => "o", |
| FormatTrait::Pointer => "p", |
| FormatTrait::Binary => "b", |
| FormatTrait::LowerHex => "x", |
| FormatTrait::UpperHex => "X", |
| }); |
| template.push('}'); |
| } |
| } |
| } |
| template.push('"'); |
| template |
| } |
