//! HIR pretty-printing is layered on top of AST pretty-printing. A number of //! the definitions in this file have equivalents in `rustc_ast_pretty`. // tidy-alphabetical-start #![recursion_limit = "256"] // tidy-alphabetical-end use std::cell::Cell; use std::vec; use rustc_abi::ExternAbi; use rustc_ast::util::parser::{self, ExprPrecedence, Fixity}; use rustc_ast::{DUMMY_NODE_ID, DelimArgs}; use rustc_ast_pretty::pp::Breaks::{Consistent, Inconsistent}; use rustc_ast_pretty::pp::{self, BoxMarker, Breaks}; use rustc_ast_pretty::pprust::state::MacHeader; use rustc_ast_pretty::pprust::{Comments, PrintState}; use rustc_hir::attrs::{AttributeKind, PrintAttribute}; use rustc_hir::{ BindingMode, ByRef, ConstArgKind, GenericArg, GenericBound, GenericParam, GenericParamKind, HirId, ImplicitSelfKind, LifetimeParamKind, Node, PatKind, PreciseCapturingArg, RangeEnd, Term, TyPatKind, }; use rustc_span::source_map::SourceMap; use rustc_span::{FileName, Ident, Span, Symbol, kw, sym}; use {rustc_ast as ast, rustc_hir as hir}; pub fn id_to_string(cx: &dyn rustc_hir::intravisit::HirTyCtxt<'_>, hir_id: HirId) -> String { to_string(&cx, |s| s.print_node(cx.hir_node(hir_id))) } pub enum AnnNode<'a> { Name(&'a Symbol), Block(&'a hir::Block<'a>), Item(&'a hir::Item<'a>), SubItem(HirId), Expr(&'a hir::Expr<'a>), Pat(&'a hir::Pat<'a>), TyPat(&'a hir::TyPat<'a>), Arm(&'a hir::Arm<'a>), } pub enum Nested { Item(hir::ItemId), TraitItem(hir::TraitItemId), ImplItem(hir::ImplItemId), ForeignItem(hir::ForeignItemId), Body(hir::BodyId), BodyParamPat(hir::BodyId, usize), } pub trait PpAnn { fn nested(&self, _state: &mut State<'_>, _nested: Nested) {} fn pre(&self, _state: &mut State<'_>, _node: AnnNode<'_>) {} fn post(&self, _state: &mut State<'_>, _node: AnnNode<'_>) {} } impl PpAnn for &dyn rustc_hir::intravisit::HirTyCtxt<'_> { fn nested(&self, state: &mut State<'_>, nested: Nested) { match nested { Nested::Item(id) => state.print_item(self.hir_item(id)), Nested::TraitItem(id) => state.print_trait_item(self.hir_trait_item(id)), Nested::ImplItem(id) => state.print_impl_item(self.hir_impl_item(id)), Nested::ForeignItem(id) => state.print_foreign_item(self.hir_foreign_item(id)), Nested::Body(id) => state.print_expr(self.hir_body(id).value), Nested::BodyParamPat(id, i) => state.print_pat(self.hir_body(id).params[i].pat), } } } pub struct State<'a> { pub s: pp::Printer, comments: Option>, attrs: &'a dyn Fn(HirId) -> &'a [hir::Attribute], ann: &'a (dyn PpAnn + 'a), } impl<'a> State<'a> { fn attrs(&self, id: HirId) -> &'a [hir::Attribute] { (self.attrs)(id) } fn precedence(&self, expr: &hir::Expr<'_>) -> ExprPrecedence { let has_attr = |id: HirId| !self.attrs(id).is_empty(); expr.precedence(&has_attr) } fn print_attrs(&mut self, attrs: &[hir::Attribute]) { if attrs.is_empty() { return; } for attr in attrs { self.print_attribute_as_style(attr, ast::AttrStyle::Outer); } self.hardbreak_if_not_bol(); } /// Print a single attribute as if it has style `style`, disregarding the /// actual style of the attribute. fn print_attribute_as_style(&mut self, attr: &hir::Attribute, style: ast::AttrStyle) { match &attr { hir::Attribute::Unparsed(unparsed) => { self.maybe_print_comment(unparsed.span.lo()); match style { ast::AttrStyle::Inner => self.word("#!["), ast::AttrStyle::Outer => self.word("#["), } self.print_attr_item(&unparsed, unparsed.span); self.word("]"); self.hardbreak() } hir::Attribute::Parsed(AttributeKind::DocComment { kind, comment, .. }) => { self.word(rustc_ast_pretty::pprust::state::doc_comment_to_string( *kind, style, *comment, )); self.hardbreak() } hir::Attribute::Parsed(pa) => { match style { ast::AttrStyle::Inner => self.word("#![attr = "), ast::AttrStyle::Outer => self.word("#[attr = "), } pa.print_attribute(self); self.word("]"); self.hardbreak() } } } fn print_attr_item(&mut self, item: &hir::AttrItem, span: Span) { let ib = self.ibox(0); let path = ast::Path { span, segments: item .path .segments .iter() .map(|i| ast::PathSegment { ident: *i, args: None, id: DUMMY_NODE_ID }) .collect(), tokens: None, }; match &item.args { hir::AttrArgs::Delimited(DelimArgs { dspan: _, delim, tokens }) => self .print_mac_common( Some(MacHeader::Path(&path)), false, None, *delim, None, &tokens, true, span, ), hir::AttrArgs::Empty => { PrintState::print_path(self, &path, false, 0); } hir::AttrArgs::Eq { eq_span: _, expr } => { PrintState::print_path(self, &path, false, 0); self.space(); self.word_space("="); let token_str = self.meta_item_lit_to_string(expr); self.word(token_str); } } self.end(ib); } fn print_node(&mut self, node: Node<'_>) { match node { Node::Param(a) => self.print_param(a), Node::Item(a) => self.print_item(a), Node::ForeignItem(a) => self.print_foreign_item(a), Node::TraitItem(a) => self.print_trait_item(a), Node::ImplItem(a) => self.print_impl_item(a), Node::Variant(a) => self.print_variant(a), Node::AnonConst(a) => self.print_anon_const(a), Node::ConstBlock(a) => self.print_inline_const(a), Node::ConstArg(a) => self.print_const_arg(a), Node::Expr(a) => self.print_expr(a), Node::ExprField(a) => self.print_expr_field(a), Node::Stmt(a) => self.print_stmt(a), Node::PathSegment(a) => self.print_path_segment(a), Node::Ty(a) => self.print_type(a), Node::AssocItemConstraint(a) => self.print_assoc_item_constraint(a), Node::TraitRef(a) => self.print_trait_ref(a), Node::OpaqueTy(_) => panic!("cannot print Node::OpaqueTy"), Node::Pat(a) => self.print_pat(a), Node::TyPat(a) => self.print_ty_pat(a), Node::PatField(a) => self.print_patfield(a), Node::PatExpr(a) => self.print_pat_expr(a), Node::Arm(a) => self.print_arm(a), Node::Infer(_) => self.word("_"), Node::PreciseCapturingNonLifetimeArg(param) => self.print_ident(param.ident), Node::Block(a) => { // Containing cbox, will be closed by print-block at `}`. let cb = self.cbox(INDENT_UNIT); // Head-ibox, will be closed by print-block after `{`. let ib = self.ibox(0); self.print_block(a, cb, ib); } Node::Lifetime(a) => self.print_lifetime(a), Node::GenericParam(_) => panic!("cannot print Node::GenericParam"), Node::Field(_) => panic!("cannot print Node::Field"), // These cases do not carry enough information in the // `hir_map` to reconstruct their full structure for pretty // printing. Node::Ctor(..) => panic!("cannot print isolated Ctor"), Node::LetStmt(a) => self.print_local_decl(a), Node::Crate(..) => panic!("cannot print Crate"), Node::WherePredicate(pred) => self.print_where_predicate(pred), Node::Synthetic => unreachable!(), Node::Err(_) => self.word("/*ERROR*/"), } } fn print_generic_arg(&mut self, generic_arg: &GenericArg<'_>, elide_lifetimes: bool) { match generic_arg { GenericArg::Lifetime(lt) if !elide_lifetimes => self.print_lifetime(lt), GenericArg::Lifetime(_) => {} GenericArg::Type(ty) => self.print_type(ty.as_unambig_ty()), GenericArg::Const(ct) => self.print_const_arg(ct.as_unambig_ct()), GenericArg::Infer(_inf) => self.word("_"), } } } impl std::ops::Deref for State<'_> { type Target = pp::Printer; fn deref(&self) -> &Self::Target { &self.s } } impl std::ops::DerefMut for State<'_> { fn deref_mut(&mut self) -> &mut Self::Target { &mut self.s } } impl<'a> PrintState<'a> for State<'a> { fn comments(&self) -> Option<&Comments<'a>> { self.comments.as_ref() } fn comments_mut(&mut self) -> Option<&mut Comments<'a>> { self.comments.as_mut() } fn ann_post(&mut self, ident: Ident) { self.ann.post(self, AnnNode::Name(&ident.name)); } fn print_generic_args(&mut self, _: &ast::GenericArgs, _colons_before_params: bool) { panic!("AST generic args printed by HIR pretty-printer"); } } const INDENT_UNIT: isize = 4; /// Requires you to pass an input filename and reader so that /// it can scan the input text for comments to copy forward. pub fn print_crate<'a>( sm: &'a SourceMap, krate: &hir::Mod<'_>, filename: FileName, input: String, attrs: &'a dyn Fn(HirId) -> &'a [hir::Attribute], ann: &'a dyn PpAnn, ) -> String { let mut s = State { s: pp::Printer::new(), comments: Some(Comments::new(sm, filename, input)), attrs, ann, }; // Print all attributes, regardless of actual style, as inner attributes // since this is the crate root with nothing above it to print outer // attributes. for attr in s.attrs(hir::CRATE_HIR_ID) { s.print_attribute_as_style(attr, ast::AttrStyle::Inner); } // When printing the AST, we sometimes need to inject `#[no_std]` here. // Since you can't compile the HIR, it's not necessary. s.print_mod(krate); s.print_remaining_comments(); s.s.eof() } fn to_string(ann: &dyn PpAnn, f: F) -> String where F: FnOnce(&mut State<'_>), { let mut printer = State { s: pp::Printer::new(), comments: None, attrs: &|_| &[], ann }; f(&mut printer); printer.s.eof() } pub fn attribute_to_string(ann: &dyn PpAnn, attr: &hir::Attribute) -> String { to_string(ann, |s| s.print_attribute_as_style(attr, ast::AttrStyle::Outer)) } pub fn ty_to_string(ann: &dyn PpAnn, ty: &hir::Ty<'_>) -> String { to_string(ann, |s| s.print_type(ty)) } pub fn qpath_to_string(ann: &dyn PpAnn, segment: &hir::QPath<'_>) -> String { to_string(ann, |s| s.print_qpath(segment, false)) } pub fn pat_to_string(ann: &dyn PpAnn, pat: &hir::Pat<'_>) -> String { to_string(ann, |s| s.print_pat(pat)) } pub fn expr_to_string(ann: &dyn PpAnn, pat: &hir::Expr<'_>) -> String { to_string(ann, |s| s.print_expr(pat)) } pub fn item_to_string(ann: &dyn PpAnn, pat: &hir::Item<'_>) -> String { to_string(ann, |s| s.print_item(pat)) } impl<'a> State<'a> { fn bclose_maybe_open(&mut self, span: rustc_span::Span, cb: Option) { self.maybe_print_comment(span.hi()); self.break_offset_if_not_bol(1, -INDENT_UNIT); self.word("}"); if let Some(cb) = cb { self.end(cb); } } fn bclose(&mut self, span: rustc_span::Span, cb: BoxMarker) { self.bclose_maybe_open(span, Some(cb)) } fn commasep_cmnt(&mut self, b: Breaks, elts: &[T], mut op: F, mut get_span: G) where F: FnMut(&mut State<'_>, &T), G: FnMut(&T) -> rustc_span::Span, { let rb = self.rbox(0, b); let len = elts.len(); let mut i = 0; for elt in elts { self.maybe_print_comment(get_span(elt).hi()); op(self, elt); i += 1; if i < len { self.word(","); self.maybe_print_trailing_comment(get_span(elt), Some(get_span(&elts[i]).hi())); self.space_if_not_bol(); } } self.end(rb); } fn commasep_exprs(&mut self, b: Breaks, exprs: &[hir::Expr<'_>]) { self.commasep_cmnt(b, exprs, |s, e| s.print_expr(e), |e| e.span); } fn print_mod(&mut self, _mod: &hir::Mod<'_>) { for &item_id in _mod.item_ids { self.ann.nested(self, Nested::Item(item_id)); } } fn print_opt_lifetime(&mut self, lifetime: &hir::Lifetime) { if !lifetime.is_elided() { self.print_lifetime(lifetime); self.nbsp(); } } fn print_type(&mut self, ty: &hir::Ty<'_>) { self.maybe_print_comment(ty.span.lo()); let ib = self.ibox(0); match ty.kind { hir::TyKind::Slice(ty) => { self.word("["); self.print_type(ty); self.word("]"); } hir::TyKind::Ptr(ref mt) => { self.word("*"); self.print_mt(mt, true); } hir::TyKind::Ref(lifetime, ref mt) => { self.word("&"); self.print_opt_lifetime(lifetime); self.print_mt(mt, false); } hir::TyKind::Never => { self.word("!"); } hir::TyKind::Tup(elts) => { self.popen(); self.commasep(Inconsistent, elts, |s, ty| s.print_type(ty)); if elts.len() == 1 { self.word(","); } self.pclose(); } hir::TyKind::FnPtr(f) => { self.print_ty_fn(f.abi, f.safety, f.decl, None, f.generic_params, f.param_idents); } hir::TyKind::UnsafeBinder(unsafe_binder) => { self.print_unsafe_binder(unsafe_binder); } hir::TyKind::OpaqueDef(..) => self.word("/*impl Trait*/"), hir::TyKind::TraitAscription(bounds) => { self.print_bounds("impl", bounds); } hir::TyKind::Path(ref qpath) => self.print_qpath(qpath, false), hir::TyKind::TraitObject(bounds, lifetime) => { let syntax = lifetime.tag(); match syntax { ast::TraitObjectSyntax::Dyn => self.word_nbsp("dyn"), ast::TraitObjectSyntax::None => {} } let mut first = true; for bound in bounds { if first { first = false; } else { self.nbsp(); self.word_space("+"); } self.print_poly_trait_ref(bound); } if !lifetime.is_elided() { self.nbsp(); self.word_space("+"); self.print_lifetime(lifetime.pointer()); } } hir::TyKind::Array(ty, ref length) => { self.word("["); self.print_type(ty); self.word("; "); self.print_const_arg(length); self.word("]"); } hir::TyKind::Typeof(ref e) => { self.word("typeof("); self.print_anon_const(e); self.word(")"); } hir::TyKind::Err(_) => { self.popen(); self.word("/*ERROR*/"); self.pclose(); } hir::TyKind::Infer(()) | hir::TyKind::InferDelegation(..) => { self.word("_"); } hir::TyKind::Pat(ty, pat) => { self.print_type(ty); self.word(" is "); self.print_ty_pat(pat); } } self.end(ib) } fn print_unsafe_binder(&mut self, unsafe_binder: &hir::UnsafeBinderTy<'_>) { let ib = self.ibox(INDENT_UNIT); self.word("unsafe"); self.print_generic_params(unsafe_binder.generic_params); self.nbsp(); self.print_type(unsafe_binder.inner_ty); self.end(ib); } fn print_foreign_item(&mut self, item: &hir::ForeignItem<'_>) { self.hardbreak_if_not_bol(); self.maybe_print_comment(item.span.lo()); self.print_attrs(self.attrs(item.hir_id())); match item.kind { hir::ForeignItemKind::Fn(sig, arg_idents, generics) => { let (cb, ib) = self.head(""); self.print_fn( sig.header, Some(item.ident.name), generics, sig.decl, arg_idents, None, ); self.end(ib); self.word(";"); self.end(cb) } hir::ForeignItemKind::Static(t, m, safety) => { self.print_safety(safety); let (cb, ib) = self.head("static"); if m.is_mut() { self.word_space("mut"); } self.print_ident(item.ident); self.word_space(":"); self.print_type(t); self.word(";"); self.end(ib); self.end(cb) } hir::ForeignItemKind::Type => { let (cb, ib) = self.head("type"); self.print_ident(item.ident); self.word(";"); self.end(ib); self.end(cb) } } } fn print_associated_const( &mut self, ident: Ident, generics: &hir::Generics<'_>, ty: &hir::Ty<'_>, default: Option, ) { self.word_space("const"); self.print_ident(ident); self.print_generic_params(generics.params); self.word_space(":"); self.print_type(ty); if let Some(expr) = default { self.space(); self.word_space("="); self.ann.nested(self, Nested::Body(expr)); } self.print_where_clause(generics); self.word(";") } fn print_associated_type( &mut self, ident: Ident, generics: &hir::Generics<'_>, bounds: Option>, ty: Option<&hir::Ty<'_>>, ) { self.word_space("type"); self.print_ident(ident); self.print_generic_params(generics.params); if let Some(bounds) = bounds { self.print_bounds(":", bounds); } self.print_where_clause(generics); if let Some(ty) = ty { self.space(); self.word_space("="); self.print_type(ty); } self.word(";") } fn print_item(&mut self, item: &hir::Item<'_>) { self.hardbreak_if_not_bol(); self.maybe_print_comment(item.span.lo()); let attrs = self.attrs(item.hir_id()); self.print_attrs(attrs); self.ann.pre(self, AnnNode::Item(item)); match item.kind { hir::ItemKind::ExternCrate(orig_name, ident) => { let (cb, ib) = self.head("extern crate"); if let Some(orig_name) = orig_name { self.print_name(orig_name); self.space(); self.word("as"); self.space(); } self.print_ident(ident); self.word(";"); self.end(ib); self.end(cb); } hir::ItemKind::Use(path, kind) => { let (cb, ib) = self.head("use"); self.print_path(path, false); match kind { hir::UseKind::Single(ident) => { if path.segments.last().unwrap().ident != ident { self.space(); self.word_space("as"); self.print_ident(ident); } self.word(";"); } hir::UseKind::Glob => self.word("::*;"), hir::UseKind::ListStem => self.word("::{};"), } self.end(ib); self.end(cb); } hir::ItemKind::Static(m, ident, ty, expr) => { let (cb, ib) = self.head("static"); if m.is_mut() { self.word_space("mut"); } self.print_ident(ident); self.word_space(":"); self.print_type(ty); self.space(); self.end(ib); self.word_space("="); self.ann.nested(self, Nested::Body(expr)); self.word(";"); self.end(cb); } hir::ItemKind::Const(ident, generics, ty, expr) => { let (cb, ib) = self.head("const"); self.print_ident(ident); self.print_generic_params(generics.params); self.word_space(":"); self.print_type(ty); self.space(); self.end(ib); self.word_space("="); self.ann.nested(self, Nested::Body(expr)); self.print_where_clause(generics); self.word(";"); self.end(cb); } hir::ItemKind::Fn { ident, sig, generics, body, .. } => { let (cb, ib) = self.head(""); self.print_fn(sig.header, Some(ident.name), generics, sig.decl, &[], Some(body)); self.word(" "); self.end(ib); self.end(cb); self.ann.nested(self, Nested::Body(body)); } hir::ItemKind::Macro(ident, macro_def, _) => { self.print_mac_def(macro_def, &ident, item.span, |_| {}); } hir::ItemKind::Mod(ident, mod_) => { let (cb, ib) = self.head("mod"); self.print_ident(ident); self.nbsp(); self.bopen(ib); self.print_mod(mod_); self.bclose(item.span, cb); } hir::ItemKind::ForeignMod { abi, items } => { let (cb, ib) = self.head("extern"); self.word_nbsp(abi.to_string()); self.bopen(ib); for &foreign_item in items { self.ann.nested(self, Nested::ForeignItem(foreign_item)); } self.bclose(item.span, cb); } hir::ItemKind::GlobalAsm { asm, .. } => { let (cb, ib) = self.head("global_asm!"); self.print_inline_asm(asm); self.word(";"); self.end(cb); self.end(ib); } hir::ItemKind::TyAlias(ident, generics, ty) => { let (cb, ib) = self.head("type"); self.print_ident(ident); self.print_generic_params(generics.params); self.end(ib); self.print_where_clause(generics); self.space(); self.word_space("="); self.print_type(ty); self.word(";"); self.end(cb); } hir::ItemKind::Enum(ident, generics, ref enum_def) => { self.print_enum_def(ident.name, generics, enum_def, item.span); } hir::ItemKind::Struct(ident, generics, ref struct_def) => { let (cb, ib) = self.head("struct"); self.print_struct(ident.name, generics, struct_def, item.span, true, cb, ib); } hir::ItemKind::Union(ident, generics, ref struct_def) => { let (cb, ib) = self.head("union"); self.print_struct(ident.name, generics, struct_def, item.span, true, cb, ib); } hir::ItemKind::Impl(&hir::Impl { constness, safety, polarity, defaultness, defaultness_span: _, generics, ref of_trait, self_ty, items, }) => { let (cb, ib) = self.head(""); self.print_defaultness(defaultness); self.print_safety(safety); self.word_nbsp("impl"); if let hir::Constness::Const = constness { self.word_nbsp("const"); } if !generics.params.is_empty() { self.print_generic_params(generics.params); self.space(); } if let hir::ImplPolarity::Negative(_) = polarity { self.word("!"); } if let Some(t) = of_trait { self.print_trait_ref(t); self.space(); self.word_space("for"); } self.print_type(self_ty); self.print_where_clause(generics); self.space(); self.bopen(ib); for &impl_item in items { self.ann.nested(self, Nested::ImplItem(impl_item)); } self.bclose(item.span, cb); } hir::ItemKind::Trait( constness, is_auto, safety, ident, generics, bounds, trait_items, ) => { let (cb, ib) = self.head(""); self.print_constness(constness); self.print_is_auto(is_auto); self.print_safety(safety); self.word_nbsp("trait"); self.print_ident(ident); self.print_generic_params(generics.params); self.print_bounds(":", bounds); self.print_where_clause(generics); self.word(" "); self.bopen(ib); for &trait_item in trait_items { self.ann.nested(self, Nested::TraitItem(trait_item)); } self.bclose(item.span, cb); } hir::ItemKind::TraitAlias(ident, generics, bounds) => { let (cb, ib) = self.head("trait"); self.print_ident(ident); self.print_generic_params(generics.params); self.nbsp(); self.print_bounds("=", bounds); self.print_where_clause(generics); self.word(";"); self.end(ib); self.end(cb); } } self.ann.post(self, AnnNode::Item(item)) } fn print_trait_ref(&mut self, t: &hir::TraitRef<'_>) { self.print_path(t.path, false); } fn print_formal_generic_params(&mut self, generic_params: &[hir::GenericParam<'_>]) { if !generic_params.is_empty() { self.word("for"); self.print_generic_params(generic_params); self.nbsp(); } } fn print_poly_trait_ref(&mut self, t: &hir::PolyTraitRef<'_>) { let hir::TraitBoundModifiers { constness, polarity } = t.modifiers; match constness { hir::BoundConstness::Never => {} hir::BoundConstness::Always(_) => self.word("const"), hir::BoundConstness::Maybe(_) => self.word("[const]"), } match polarity { hir::BoundPolarity::Positive => {} hir::BoundPolarity::Negative(_) => self.word("!"), hir::BoundPolarity::Maybe(_) => self.word("?"), } self.print_formal_generic_params(t.bound_generic_params); self.print_trait_ref(&t.trait_ref); } fn print_enum_def( &mut self, name: Symbol, generics: &hir::Generics<'_>, enum_def: &hir::EnumDef<'_>, span: rustc_span::Span, ) { let (cb, ib) = self.head("enum"); self.print_name(name); self.print_generic_params(generics.params); self.print_where_clause(generics); self.space(); self.print_variants(enum_def.variants, span, cb, ib); } fn print_variants( &mut self, variants: &[hir::Variant<'_>], span: rustc_span::Span, cb: BoxMarker, ib: BoxMarker, ) { self.bopen(ib); for v in variants { self.space_if_not_bol(); self.maybe_print_comment(v.span.lo()); self.print_attrs(self.attrs(v.hir_id)); let ib = self.ibox(INDENT_UNIT); self.print_variant(v); self.word(","); self.end(ib); self.maybe_print_trailing_comment(v.span, None); } self.bclose(span, cb) } fn print_defaultness(&mut self, defaultness: hir::Defaultness) { match defaultness { hir::Defaultness::Default { .. } => self.word_nbsp("default"), hir::Defaultness::Final => (), } } fn print_struct( &mut self, name: Symbol, generics: &hir::Generics<'_>, struct_def: &hir::VariantData<'_>, span: rustc_span::Span, print_finalizer: bool, cb: BoxMarker, ib: BoxMarker, ) { self.print_name(name); self.print_generic_params(generics.params); match struct_def { hir::VariantData::Tuple(..) | hir::VariantData::Unit(..) => { if let hir::VariantData::Tuple(..) = struct_def { self.popen(); self.commasep(Inconsistent, struct_def.fields(), |s, field| { s.maybe_print_comment(field.span.lo()); s.print_attrs(s.attrs(field.hir_id)); s.print_type(field.ty); }); self.pclose(); } self.print_where_clause(generics); if print_finalizer { self.word(";"); } self.end(ib); self.end(cb); } hir::VariantData::Struct { .. } => { self.print_where_clause(generics); self.nbsp(); self.bopen(ib); self.hardbreak_if_not_bol(); for field in struct_def.fields() { self.hardbreak_if_not_bol(); self.maybe_print_comment(field.span.lo()); self.print_attrs(self.attrs(field.hir_id)); self.print_ident(field.ident); self.word_nbsp(":"); self.print_type(field.ty); self.word(","); } self.bclose(span, cb) } } } pub fn print_variant(&mut self, v: &hir::Variant<'_>) { let (cb, ib) = self.head(""); let generics = hir::Generics::empty(); self.print_struct(v.ident.name, generics, &v.data, v.span, false, cb, ib); if let Some(ref d) = v.disr_expr { self.space(); self.word_space("="); self.print_anon_const(d); } } fn print_method_sig( &mut self, ident: Ident, m: &hir::FnSig<'_>, generics: &hir::Generics<'_>, arg_idents: &[Option], body_id: Option, ) { self.print_fn(m.header, Some(ident.name), generics, m.decl, arg_idents, body_id); } fn print_trait_item(&mut self, ti: &hir::TraitItem<'_>) { self.ann.pre(self, AnnNode::SubItem(ti.hir_id())); self.hardbreak_if_not_bol(); self.maybe_print_comment(ti.span.lo()); self.print_attrs(self.attrs(ti.hir_id())); match ti.kind { hir::TraitItemKind::Const(ty, default) => { self.print_associated_const(ti.ident, ti.generics, ty, default); } hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Required(arg_idents)) => { self.print_method_sig(ti.ident, sig, ti.generics, arg_idents, None); self.word(";"); } hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(body)) => { let (cb, ib) = self.head(""); self.print_method_sig(ti.ident, sig, ti.generics, &[], Some(body)); self.nbsp(); self.end(ib); self.end(cb); self.ann.nested(self, Nested::Body(body)); } hir::TraitItemKind::Type(bounds, default) => { self.print_associated_type(ti.ident, ti.generics, Some(bounds), default); } } self.ann.post(self, AnnNode::SubItem(ti.hir_id())) } fn print_impl_item(&mut self, ii: &hir::ImplItem<'_>) { self.ann.pre(self, AnnNode::SubItem(ii.hir_id())); self.hardbreak_if_not_bol(); self.maybe_print_comment(ii.span.lo()); self.print_attrs(self.attrs(ii.hir_id())); match ii.kind { hir::ImplItemKind::Const(ty, expr) => { self.print_associated_const(ii.ident, ii.generics, ty, Some(expr)); } hir::ImplItemKind::Fn(ref sig, body) => { let (cb, ib) = self.head(""); self.print_method_sig(ii.ident, sig, ii.generics, &[], Some(body)); self.nbsp(); self.end(ib); self.end(cb); self.ann.nested(self, Nested::Body(body)); } hir::ImplItemKind::Type(ty) => { self.print_associated_type(ii.ident, ii.generics, None, Some(ty)); } } self.ann.post(self, AnnNode::SubItem(ii.hir_id())) } fn print_local( &mut self, super_: bool, init: Option<&hir::Expr<'_>>, els: Option<&hir::Block<'_>>, decl: impl Fn(&mut Self), ) { self.space_if_not_bol(); let ibm1 = self.ibox(INDENT_UNIT); if super_ { self.word_nbsp("super"); } self.word_nbsp("let"); let ibm2 = self.ibox(INDENT_UNIT); decl(self); self.end(ibm2); if let Some(init) = init { self.nbsp(); self.word_space("="); self.print_expr(init); } if let Some(els) = els { self.nbsp(); self.word_space("else"); // containing cbox, will be closed by print-block at `}` let cb = self.cbox(0); // head-box, will be closed by print-block after `{` let ib = self.ibox(0); self.print_block(els, cb, ib); } self.end(ibm1) } fn print_stmt(&mut self, st: &hir::Stmt<'_>) { self.maybe_print_comment(st.span.lo()); match st.kind { hir::StmtKind::Let(loc) => { self.print_local(loc.super_.is_some(), loc.init, loc.els, |this| { this.print_local_decl(loc) }); } hir::StmtKind::Item(item) => self.ann.nested(self, Nested::Item(item)), hir::StmtKind::Expr(expr) => { self.space_if_not_bol(); self.print_expr(expr); } hir::StmtKind::Semi(expr) => { self.space_if_not_bol(); self.print_expr(expr); self.word(";"); } } if stmt_ends_with_semi(&st.kind) { self.word(";"); } self.maybe_print_trailing_comment(st.span, None) } fn print_block(&mut self, blk: &hir::Block<'_>, cb: BoxMarker, ib: BoxMarker) { self.print_block_maybe_unclosed(blk, Some(cb), ib) } fn print_block_unclosed(&mut self, blk: &hir::Block<'_>, ib: BoxMarker) { self.print_block_maybe_unclosed(blk, None, ib) } fn print_block_maybe_unclosed( &mut self, blk: &hir::Block<'_>, cb: Option, ib: BoxMarker, ) { match blk.rules { hir::BlockCheckMode::UnsafeBlock(..) => self.word_space("unsafe"), hir::BlockCheckMode::DefaultBlock => (), } self.maybe_print_comment(blk.span.lo()); self.ann.pre(self, AnnNode::Block(blk)); self.bopen(ib); for st in blk.stmts { self.print_stmt(st); } if let Some(expr) = blk.expr { self.space_if_not_bol(); self.print_expr(expr); self.maybe_print_trailing_comment(expr.span, Some(blk.span.hi())); } self.bclose_maybe_open(blk.span, cb); self.ann.post(self, AnnNode::Block(blk)) } fn print_else(&mut self, els: Option<&hir::Expr<'_>>) { if let Some(els_inner) = els { match els_inner.kind { // Another `else if` block. hir::ExprKind::If(i, hir::Expr { kind: hir::ExprKind::Block(t, None), .. }, e) => { let cb = self.cbox(0); let ib = self.ibox(0); self.word(" else if "); self.print_expr_as_cond(i); self.space(); self.print_block(t, cb, ib); self.print_else(e); } // Final `else` block. hir::ExprKind::Block(b, None) => { let cb = self.cbox(0); let ib = self.ibox(0); self.word(" else "); self.print_block(b, cb, ib); } // Constraints would be great here! _ => { panic!("print_if saw if with weird alternative"); } } } } fn print_if( &mut self, test: &hir::Expr<'_>, blk: &hir::Expr<'_>, elseopt: Option<&hir::Expr<'_>>, ) { match blk.kind { hir::ExprKind::Block(blk, None) => { let cb = self.cbox(0); let ib = self.ibox(0); self.word_nbsp("if"); self.print_expr_as_cond(test); self.space(); self.print_block(blk, cb, ib); self.print_else(elseopt) } _ => panic!("non-block then expr"), } } fn print_anon_const(&mut self, constant: &hir::AnonConst) { self.ann.nested(self, Nested::Body(constant.body)) } fn print_const_arg(&mut self, const_arg: &hir::ConstArg<'_>) { match &const_arg.kind { ConstArgKind::Path(qpath) => self.print_qpath(qpath, true), ConstArgKind::Anon(anon) => self.print_anon_const(anon), ConstArgKind::Infer(..) => self.word("_"), } } fn print_call_post(&mut self, args: &[hir::Expr<'_>]) { self.popen(); self.commasep_exprs(Inconsistent, args); self.pclose() } /// 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: &hir::Expr<'_>) { self.print_expr_cond_paren(expr, Self::cond_needs_par(expr)) } /// Prints `expr` or `(expr)` when `needs_par` holds. fn print_expr_cond_paren(&mut self, expr: &hir::Expr<'_>, needs_par: bool) { if needs_par { self.popen(); } if let hir::ExprKind::DropTemps(actual_expr) = expr.kind { self.print_expr(actual_expr); } else { self.print_expr(expr); } if needs_par { self.pclose(); } } /// Print a `let pat = expr` expression. fn print_let(&mut self, pat: &hir::Pat<'_>, ty: Option<&hir::Ty<'_>>, init: &hir::Expr<'_>) { self.word_space("let"); self.print_pat(pat); if let Some(ty) = ty { self.word_space(":"); self.print_type(ty); } self.space(); self.word_space("="); let npals = || parser::needs_par_as_let_scrutinee(self.precedence(init)); self.print_expr_cond_paren(init, Self::cond_needs_par(init) || npals()) } // 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: &hir::Expr<'_>) -> bool { match expr.kind { hir::ExprKind::Break(..) | hir::ExprKind::Closure { .. } | hir::ExprKind::Ret(..) => { true } _ => contains_exterior_struct_lit(expr), } } fn print_expr_vec(&mut self, exprs: &[hir::Expr<'_>]) { let ib = self.ibox(INDENT_UNIT); self.word("["); self.commasep_exprs(Inconsistent, exprs); self.word("]"); self.end(ib) } fn print_inline_const(&mut self, constant: &hir::ConstBlock) { let ib = self.ibox(INDENT_UNIT); self.word_space("const"); self.ann.nested(self, Nested::Body(constant.body)); self.end(ib) } fn print_expr_repeat(&mut self, element: &hir::Expr<'_>, count: &hir::ConstArg<'_>) { let ib = self.ibox(INDENT_UNIT); self.word("["); self.print_expr(element); self.word_space(";"); self.print_const_arg(count); self.word("]"); self.end(ib) } fn print_expr_struct( &mut self, qpath: &hir::QPath<'_>, fields: &[hir::ExprField<'_>], wth: hir::StructTailExpr<'_>, ) { self.print_qpath(qpath, true); self.nbsp(); self.word_space("{"); self.commasep_cmnt(Consistent, fields, |s, field| s.print_expr_field(field), |f| f.span); match wth { hir::StructTailExpr::Base(expr) => { let ib = self.ibox(INDENT_UNIT); if !fields.is_empty() { self.word(","); self.space(); } self.word(".."); self.print_expr(expr); self.end(ib); } hir::StructTailExpr::DefaultFields(_) => { let ib = self.ibox(INDENT_UNIT); if !fields.is_empty() { self.word(","); self.space(); } self.word(".."); self.end(ib); } hir::StructTailExpr::None => {} } self.space(); self.word("}"); } fn print_expr_field(&mut self, field: &hir::ExprField<'_>) { let cb = self.cbox(INDENT_UNIT); self.print_attrs(self.attrs(field.hir_id)); if !field.is_shorthand { self.print_ident(field.ident); self.word_space(":"); } self.print_expr(field.expr); self.end(cb) } fn print_expr_tup(&mut self, exprs: &[hir::Expr<'_>]) { self.popen(); self.commasep_exprs(Inconsistent, exprs); if exprs.len() == 1 { self.word(","); } self.pclose() } fn print_expr_call(&mut self, func: &hir::Expr<'_>, args: &[hir::Expr<'_>]) { let needs_paren = match func.kind { hir::ExprKind::Field(..) => true, _ => self.precedence(func) < ExprPrecedence::Unambiguous, }; self.print_expr_cond_paren(func, needs_paren); self.print_call_post(args) } fn print_expr_method_call( &mut self, segment: &hir::PathSegment<'_>, receiver: &hir::Expr<'_>, args: &[hir::Expr<'_>], ) { let base_args = args; self.print_expr_cond_paren( receiver, self.precedence(receiver) < ExprPrecedence::Unambiguous, ); self.word("."); self.print_ident(segment.ident); let generic_args = segment.args(); if !generic_args.args.is_empty() || !generic_args.constraints.is_empty() { self.print_generic_args(generic_args, true); } self.print_call_post(base_args) } fn print_expr_binary(&mut self, op: hir::BinOpKind, lhs: &hir::Expr<'_>, rhs: &hir::Expr<'_>) { let binop_prec = op.precedence(); let left_prec = self.precedence(lhs); let right_prec = self.precedence(rhs); let (mut left_needs_paren, right_needs_paren) = match op.fixity() { Fixity::Left => (left_prec < binop_prec, right_prec <= binop_prec), Fixity::Right => (left_prec <= binop_prec, right_prec < binop_prec), Fixity::None => (left_prec <= binop_prec, right_prec <= binop_prec), }; match (&lhs.kind, op) { // 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. (&hir::ExprKind::Cast { .. }, hir::BinOpKind::Lt | hir::BinOpKind::Shl) => { left_needs_paren = true; } (&hir::ExprKind::Let { .. }, _) if !parser::needs_par_as_let_scrutinee(binop_prec) => { left_needs_paren = true; } _ => {} } self.print_expr_cond_paren(lhs, left_needs_paren); self.space(); self.word_space(op.as_str()); self.print_expr_cond_paren(rhs, right_needs_paren); } fn print_expr_unary(&mut self, op: hir::UnOp, expr: &hir::Expr<'_>) { self.word(op.as_str()); self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Prefix); } fn print_expr_addr_of( &mut self, kind: hir::BorrowKind, mutability: hir::Mutability, expr: &hir::Expr<'_>, ) { self.word("&"); match kind { hir::BorrowKind::Ref => self.print_mutability(mutability, false), hir::BorrowKind::Raw => { self.word_nbsp("raw"); self.print_mutability(mutability, true); } hir::BorrowKind::Pin => { self.word_nbsp("pin"); self.print_mutability(mutability, true); } } self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Prefix); } fn print_literal(&mut self, lit: &hir::Lit) { self.maybe_print_comment(lit.span.lo()); self.word(lit.node.to_string()) } fn print_inline_asm(&mut self, asm: &hir::InlineAsm<'_>) { enum AsmArg<'a> { Template(String), Operand(&'a hir::InlineAsmOperand<'a>), Options(ast::InlineAsmOptions), } let mut args = vec![AsmArg::Template(ast::InlineAsmTemplatePiece::to_string(asm.template))]; args.extend(asm.operands.iter().map(|(o, _)| AsmArg::Operand(o))); if !asm.options.is_empty() { args.push(AsmArg::Options(asm.options)); } self.popen(); self.commasep(Consistent, &args, |s, arg| match *arg { AsmArg::Template(ref template) => s.print_string(template, ast::StrStyle::Cooked), AsmArg::Operand(op) => match *op { hir::InlineAsmOperand::In { reg, expr } => { s.word("in"); s.popen(); s.word(format!("{reg}")); s.pclose(); s.space(); s.print_expr(expr); } hir::InlineAsmOperand::Out { reg, late, ref expr } => { s.word(if late { "lateout" } else { "out" }); s.popen(); s.word(format!("{reg}")); s.pclose(); s.space(); match expr { Some(expr) => s.print_expr(expr), None => s.word("_"), } } hir::InlineAsmOperand::InOut { reg, late, expr } => { s.word(if late { "inlateout" } else { "inout" }); s.popen(); s.word(format!("{reg}")); s.pclose(); s.space(); s.print_expr(expr); } hir::InlineAsmOperand::SplitInOut { reg, late, in_expr, ref out_expr } => { s.word(if late { "inlateout" } else { "inout" }); s.popen(); s.word(format!("{reg}")); s.pclose(); s.space(); s.print_expr(in_expr); s.space(); s.word_space("=>"); match out_expr { Some(out_expr) => s.print_expr(out_expr), None => s.word("_"), } } hir::InlineAsmOperand::Const { ref anon_const } => { s.word("const"); s.space(); // Not using `print_inline_const` to avoid additional `const { ... }` s.ann.nested(s, Nested::Body(anon_const.body)) } hir::InlineAsmOperand::SymFn { ref expr } => { s.word("sym_fn"); s.space(); s.print_expr(expr); } hir::InlineAsmOperand::SymStatic { ref path, def_id: _ } => { s.word("sym_static"); s.space(); s.print_qpath(path, true); } hir::InlineAsmOperand::Label { block } => { let (cb, ib) = s.head("label"); s.print_block(block, cb, ib); } }, AsmArg::Options(opts) => { s.word("options"); s.popen(); s.commasep(Inconsistent, &opts.human_readable_names(), |s, &opt| { s.word(opt); }); s.pclose(); } }); self.pclose(); } fn print_expr(&mut self, expr: &hir::Expr<'_>) { self.maybe_print_comment(expr.span.lo()); self.print_attrs(self.attrs(expr.hir_id)); let ib = self.ibox(INDENT_UNIT); self.ann.pre(self, AnnNode::Expr(expr)); match expr.kind { hir::ExprKind::Array(exprs) => { self.print_expr_vec(exprs); } hir::ExprKind::ConstBlock(ref anon_const) => { self.print_inline_const(anon_const); } hir::ExprKind::Repeat(element, ref count) => { self.print_expr_repeat(element, count); } hir::ExprKind::Struct(qpath, fields, wth) => { self.print_expr_struct(qpath, fields, wth); } hir::ExprKind::Tup(exprs) => { self.print_expr_tup(exprs); } hir::ExprKind::Call(func, args) => { self.print_expr_call(func, args); } hir::ExprKind::MethodCall(segment, receiver, args, _) => { self.print_expr_method_call(segment, receiver, args); } hir::ExprKind::Use(expr, _) => { self.print_expr(expr); self.word(".use"); } hir::ExprKind::Binary(op, lhs, rhs) => { self.print_expr_binary(op.node, lhs, rhs); } hir::ExprKind::Unary(op, expr) => { self.print_expr_unary(op, expr); } hir::ExprKind::AddrOf(k, m, expr) => { self.print_expr_addr_of(k, m, expr); } hir::ExprKind::Lit(lit) => { self.print_literal(&lit); } hir::ExprKind::Cast(expr, ty) => { self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Cast); self.space(); self.word_space("as"); self.print_type(ty); } hir::ExprKind::Type(expr, ty) => { self.word("type_ascribe!("); let ib = self.ibox(0); self.print_expr(expr); self.word(","); self.space_if_not_bol(); self.print_type(ty); self.end(ib); self.word(")"); } hir::ExprKind::DropTemps(init) => { // Print `{`: let cb = self.cbox(0); let ib = self.ibox(0); self.bopen(ib); // Print `let _t = $init;`: let temp = Ident::with_dummy_span(sym::_t); self.print_local(false, Some(init), None, |this| this.print_ident(temp)); self.word(";"); // Print `_t`: self.space_if_not_bol(); self.print_ident(temp); // Print `}`: self.bclose_maybe_open(expr.span, Some(cb)); } hir::ExprKind::Let(&hir::LetExpr { pat, ty, init, .. }) => { self.print_let(pat, ty, init); } hir::ExprKind::If(test, blk, elseopt) => { self.print_if(test, blk, elseopt); } hir::ExprKind::Loop(blk, opt_label, _, _) => { let cb = self.cbox(0); let ib = self.ibox(0); if let Some(label) = opt_label { self.print_ident(label.ident); self.word_space(":"); } self.word_nbsp("loop"); self.print_block(blk, cb, ib); } hir::ExprKind::Match(expr, arms, _) => { let cb = self.cbox(0); let ib = self.ibox(0); self.word_nbsp("match"); self.print_expr_as_cond(expr); self.space(); self.bopen(ib); for arm in arms { self.print_arm(arm); } self.bclose(expr.span, cb); } hir::ExprKind::Closure(&hir::Closure { binder, constness, capture_clause, bound_generic_params, fn_decl, body, fn_decl_span: _, fn_arg_span: _, kind: _, def_id: _, }) => { self.print_closure_binder(binder, bound_generic_params); self.print_constness(constness); self.print_capture_clause(capture_clause); self.print_closure_params(fn_decl, body); self.space(); // This is a bare expression. self.ann.nested(self, Nested::Body(body)); } hir::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 `}` let cb = self.cbox(0); // head-box, will be closed by print-block after `{` let ib = self.ibox(0); self.print_block(blk, cb, ib); } hir::ExprKind::Assign(lhs, rhs, _) => { self.print_expr_cond_paren(lhs, self.precedence(lhs) <= ExprPrecedence::Assign); self.space(); self.word_space("="); self.print_expr_cond_paren(rhs, self.precedence(rhs) < ExprPrecedence::Assign); } hir::ExprKind::AssignOp(op, lhs, rhs) => { self.print_expr_cond_paren(lhs, self.precedence(lhs) <= ExprPrecedence::Assign); self.space(); self.word_space(op.node.as_str()); self.print_expr_cond_paren(rhs, self.precedence(rhs) < ExprPrecedence::Assign); } hir::ExprKind::Field(expr, ident) => { self.print_expr_cond_paren( expr, self.precedence(expr) < ExprPrecedence::Unambiguous, ); self.word("."); self.print_ident(ident); } hir::ExprKind::Index(expr, index, _) => { self.print_expr_cond_paren( expr, self.precedence(expr) < ExprPrecedence::Unambiguous, ); self.word("["); self.print_expr(index); self.word("]"); } hir::ExprKind::Path(ref qpath) => self.print_qpath(qpath, true), hir::ExprKind::Break(destination, opt_expr) => { self.word("break"); if let Some(label) = destination.label { self.space(); self.print_ident(label.ident); } if let Some(expr) = opt_expr { self.space(); self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Jump); } } hir::ExprKind::Continue(destination) => { self.word("continue"); if let Some(label) = destination.label { self.space(); self.print_ident(label.ident); } } hir::ExprKind::Ret(result) => { self.word("return"); if let Some(expr) = result { self.word(" "); self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Jump); } } hir::ExprKind::Become(result) => { self.word("become"); self.word(" "); self.print_expr_cond_paren(result, self.precedence(result) < ExprPrecedence::Jump); } hir::ExprKind::InlineAsm(asm) => { self.word("asm!"); self.print_inline_asm(asm); } hir::ExprKind::OffsetOf(container, fields) => { self.word("offset_of!("); 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.word(")"); } hir::ExprKind::UnsafeBinderCast(kind, expr, ty) => { match kind { ast::UnsafeBinderCastKind::Wrap => self.word("wrap_binder!("), ast::UnsafeBinderCastKind::Unwrap => self.word("unwrap_binder!("), } self.print_expr(expr); if let Some(ty) = ty { self.word(","); self.space(); self.print_type(ty); } self.word(")"); } hir::ExprKind::Yield(expr, _) => { self.word_space("yield"); self.print_expr_cond_paren(expr, self.precedence(expr) < ExprPrecedence::Jump); } hir::ExprKind::Err(_) => { self.popen(); self.word("/*ERROR*/"); self.pclose(); } } self.ann.post(self, AnnNode::Expr(expr)); self.end(ib) } fn print_local_decl(&mut self, loc: &hir::LetStmt<'_>) { self.print_pat(loc.pat); if let Some(ty) = loc.ty { self.word_space(":"); self.print_type(ty); } } fn print_name(&mut self, name: Symbol) { self.print_ident(Ident::with_dummy_span(name)) } fn print_path(&mut self, path: &hir::Path<'_, R>, colons_before_params: bool) { self.maybe_print_comment(path.span.lo()); for (i, segment) in path.segments.iter().enumerate() { if i > 0 { self.word("::") } if segment.ident.name != kw::PathRoot { self.print_ident(segment.ident); self.print_generic_args(segment.args(), colons_before_params); } } } fn print_path_segment(&mut self, segment: &hir::PathSegment<'_>) { if segment.ident.name != kw::PathRoot { self.print_ident(segment.ident); self.print_generic_args(segment.args(), false); } } fn print_qpath(&mut self, qpath: &hir::QPath<'_>, colons_before_params: bool) { match *qpath { hir::QPath::Resolved(None, path) => self.print_path(path, colons_before_params), hir::QPath::Resolved(Some(qself), path) => { self.word("<"); self.print_type(qself); self.space(); self.word_space("as"); for (i, segment) in path.segments[..path.segments.len() - 1].iter().enumerate() { if i > 0 { self.word("::") } if segment.ident.name != kw::PathRoot { self.print_ident(segment.ident); self.print_generic_args(segment.args(), colons_before_params); } } self.word(">"); self.word("::"); let item_segment = path.segments.last().unwrap(); self.print_ident(item_segment.ident); self.print_generic_args(item_segment.args(), colons_before_params) } hir::QPath::TypeRelative(qself, item_segment) => { // If we've got a compound-qualified-path, let's push an additional pair of angle // brackets, so that we pretty-print `<::C>` as `::C`, instead of just // `A::B::C` (since the latter could be ambiguous to the user) if let hir::TyKind::Path(hir::QPath::Resolved(None, _)) = qself.kind { self.print_type(qself); } else { self.word("<"); self.print_type(qself); self.word(">"); } self.word("::"); self.print_ident(item_segment.ident); self.print_generic_args(item_segment.args(), colons_before_params) } hir::QPath::LangItem(lang_item, span) => { self.word("#[lang = \""); self.print_ident(Ident::new(lang_item.name(), span)); self.word("\"]"); } } } fn print_generic_args( &mut self, generic_args: &hir::GenericArgs<'_>, colons_before_params: bool, ) { match generic_args.parenthesized { hir::GenericArgsParentheses::No => { let start = if colons_before_params { "::<" } else { "<" }; let empty = Cell::new(true); let start_or_comma = |this: &mut Self| { if empty.get() { empty.set(false); this.word(start) } else { this.word_space(",") } }; let mut nonelided_generic_args: bool = false; let elide_lifetimes = generic_args.args.iter().all(|arg| match arg { GenericArg::Lifetime(lt) if lt.is_elided() => true, GenericArg::Lifetime(_) => { nonelided_generic_args = true; false } _ => { nonelided_generic_args = true; true } }); if nonelided_generic_args { start_or_comma(self); self.commasep(Inconsistent, generic_args.args, |s, generic_arg| { s.print_generic_arg(generic_arg, elide_lifetimes) }); } for constraint in generic_args.constraints { start_or_comma(self); self.print_assoc_item_constraint(constraint); } if !empty.get() { self.word(">") } } hir::GenericArgsParentheses::ParenSugar => { let (inputs, output) = generic_args.paren_sugar_inputs_output().unwrap(); self.word("("); self.commasep(Inconsistent, inputs, |s, ty| s.print_type(ty)); self.word(")"); self.space_if_not_bol(); self.word_space("->"); self.print_type(output); } hir::GenericArgsParentheses::ReturnTypeNotation => { self.word("(..)"); } } } fn print_assoc_item_constraint(&mut self, constraint: &hir::AssocItemConstraint<'_>) { self.print_ident(constraint.ident); self.print_generic_args(constraint.gen_args, false); self.space(); match constraint.kind { hir::AssocItemConstraintKind::Equality { ref term } => { self.word_space("="); match term { Term::Ty(ty) => self.print_type(ty), Term::Const(c) => self.print_const_arg(c), } } hir::AssocItemConstraintKind::Bound { bounds } => { self.print_bounds(":", bounds); } } } fn print_pat_expr(&mut self, expr: &hir::PatExpr<'_>) { match &expr.kind { hir::PatExprKind::Lit { lit, negated } => { if *negated { self.word("-"); } self.print_literal(lit); } hir::PatExprKind::ConstBlock(c) => self.print_inline_const(c), hir::PatExprKind::Path(qpath) => self.print_qpath(qpath, true), } } fn print_ty_pat(&mut self, pat: &hir::TyPat<'_>) { self.maybe_print_comment(pat.span.lo()); self.ann.pre(self, AnnNode::TyPat(pat)); // Pat isn't normalized, but the beauty of it // is that it doesn't matter match pat.kind { TyPatKind::Range(begin, end) => { self.print_const_arg(begin); self.word("..="); self.print_const_arg(end); } TyPatKind::Or(patterns) => { self.popen(); let mut first = true; for pat in patterns { if first { first = false; } else { self.word(" | "); } self.print_ty_pat(pat); } self.pclose(); } TyPatKind::Err(_) => { self.popen(); self.word("/*ERROR*/"); self.pclose(); } } self.ann.post(self, AnnNode::TyPat(pat)) } fn print_pat(&mut self, pat: &hir::Pat<'_>) { self.maybe_print_comment(pat.span.lo()); self.ann.pre(self, AnnNode::Pat(pat)); // Pat isn't normalized, but the beauty of it is that it doesn't matter. match pat.kind { // Printing `_` isn't ideal for a missing pattern, but it's easy and good enough. // E.g. `fn(u32)` gets printed as `fn(_: u32)`. PatKind::Missing => self.word("_"), PatKind::Wild => self.word("_"), PatKind::Never => self.word("!"), PatKind::Binding(BindingMode(by_ref, mutbl), _, ident, sub) => { if mutbl.is_mut() { self.word_nbsp("mut"); } if let ByRef::Yes(rmutbl) = by_ref { self.word_nbsp("ref"); if rmutbl.is_mut() { self.word_nbsp("mut"); } } self.print_ident(ident); if let Some(p) = sub { self.word("@"); self.print_pat(p); } } PatKind::TupleStruct(ref qpath, elts, ddpos) => { self.print_qpath(qpath, true); self.popen(); if let Some(ddpos) = ddpos.as_opt_usize() { self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(p)); if ddpos != 0 { self.word_space(","); } self.word(".."); if ddpos != elts.len() { self.word(","); self.commasep(Inconsistent, &elts[ddpos..], |s, p| s.print_pat(p)); } } else { self.commasep(Inconsistent, elts, |s, p| s.print_pat(p)); } self.pclose(); } PatKind::Struct(ref qpath, fields, etc) => { self.print_qpath(qpath, true); self.nbsp(); self.word("{"); let empty = fields.is_empty() && !etc; if !empty { self.space(); } self.commasep_cmnt(Consistent, fields, |s, f| s.print_patfield(f), |f| f.pat.span); if etc { if !fields.is_empty() { self.word_space(","); } self.word(".."); } if !empty { self.space(); } self.word("}"); } PatKind::Or(pats) => { self.strsep("|", true, Inconsistent, pats, |s, p| s.print_pat(p)); } PatKind::Tuple(elts, ddpos) => { self.popen(); if let Some(ddpos) = ddpos.as_opt_usize() { self.commasep(Inconsistent, &elts[..ddpos], |s, p| s.print_pat(p)); if ddpos != 0 { self.word_space(","); } self.word(".."); if ddpos != elts.len() { self.word(","); self.commasep(Inconsistent, &elts[ddpos..], |s, p| s.print_pat(p)); } } else { self.commasep(Inconsistent, elts, |s, p| s.print_pat(p)); if elts.len() == 1 { self.word(","); } } self.pclose(); } PatKind::Box(inner) => { let is_range_inner = matches!(inner.kind, PatKind::Range(..)); self.word("box "); if is_range_inner { self.popen(); } self.print_pat(inner); if is_range_inner { self.pclose(); } } PatKind::Deref(inner) => { self.word("deref!"); self.popen(); self.print_pat(inner); self.pclose(); } PatKind::Ref(inner, mutbl) => { let is_range_inner = matches!(inner.kind, PatKind::Range(..)); self.word("&"); self.word(mutbl.prefix_str()); if is_range_inner { self.popen(); } self.print_pat(inner); if is_range_inner { self.pclose(); } } PatKind::Expr(e) => self.print_pat_expr(e), PatKind::Range(begin, end, end_kind) => { if let Some(expr) = begin { self.print_pat_expr(expr); } match end_kind { RangeEnd::Included => self.word("..."), RangeEnd::Excluded => self.word(".."), } if let Some(expr) = end { self.print_pat_expr(expr); } } PatKind::Slice(before, slice, after) => { self.word("["); self.commasep(Inconsistent, before, |s, p| s.print_pat(p)); if let Some(p) = slice { if !before.is_empty() { self.word_space(","); } if let PatKind::Wild = p.kind { // Print nothing. } else { self.print_pat(p); } self.word(".."); if !after.is_empty() { self.word_space(","); } } self.commasep(Inconsistent, after, |s, p| s.print_pat(p)); self.word("]"); } PatKind::Guard(inner, cond) => { self.print_pat(inner); self.space(); self.word_space("if"); self.print_expr(cond); } PatKind::Err(_) => { self.popen(); self.word("/*ERROR*/"); self.pclose(); } } self.ann.post(self, AnnNode::Pat(pat)) } fn print_patfield(&mut self, field: &hir::PatField<'_>) { if self.attrs(field.hir_id).is_empty() { self.space(); } let cb = self.cbox(INDENT_UNIT); self.print_attrs(self.attrs(field.hir_id)); if !field.is_shorthand { self.print_ident(field.ident); self.word_nbsp(":"); } self.print_pat(field.pat); self.end(cb); } fn print_param(&mut self, arg: &hir::Param<'_>) { self.print_attrs(self.attrs(arg.hir_id)); self.print_pat(arg.pat); } fn print_implicit_self(&mut self, implicit_self_kind: &hir::ImplicitSelfKind) { match implicit_self_kind { ImplicitSelfKind::Imm => { self.word("self"); } ImplicitSelfKind::Mut => { self.print_mutability(hir::Mutability::Mut, false); self.word("self"); } ImplicitSelfKind::RefImm => { self.word("&"); self.word("self"); } ImplicitSelfKind::RefMut => { self.word("&"); self.print_mutability(hir::Mutability::Mut, false); self.word("self"); } ImplicitSelfKind::None => unreachable!(), } } fn print_arm(&mut self, arm: &hir::Arm<'_>) { // I have no idea why this check is necessary, but here it // is :( if self.attrs(arm.hir_id).is_empty() { self.space(); } let cb = self.cbox(INDENT_UNIT); self.ann.pre(self, AnnNode::Arm(arm)); let ib = self.ibox(0); self.print_attrs(self.attrs(arm.hir_id)); self.print_pat(arm.pat); self.space(); if let Some(ref g) = arm.guard { self.word_space("if"); self.print_expr(g); self.space(); } self.word_space("=>"); match arm.body.kind { hir::ExprKind::Block(blk, opt_label) => { if let Some(label) = opt_label { self.print_ident(label.ident); self.word_space(":"); } self.print_block_unclosed(blk, ib); // If it is a user-provided unsafe block, print a comma after it if let hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::UserProvided) = blk.rules { self.word(","); } } _ => { self.end(ib); self.print_expr(arm.body); self.word(","); } } self.ann.post(self, AnnNode::Arm(arm)); self.end(cb) } fn print_fn( &mut self, header: hir::FnHeader, name: Option, generics: &hir::Generics<'_>, decl: &hir::FnDecl<'_>, arg_idents: &[Option], body_id: Option, ) { self.print_fn_header_info(header); if let Some(name) = name { self.nbsp(); self.print_name(name); } self.print_generic_params(generics.params); self.popen(); // Make sure we aren't supplied *both* `arg_idents` and `body_id`. assert!(arg_idents.is_empty() || body_id.is_none()); let mut i = 0; let mut print_arg = |s: &mut Self, ty: Option<&hir::Ty<'_>>| { if i == 0 && decl.implicit_self.has_implicit_self() { s.print_implicit_self(&decl.implicit_self); } else { if let Some(arg_ident) = arg_idents.get(i) { if let Some(arg_ident) = arg_ident { s.word(arg_ident.to_string()); s.word(":"); s.space(); } } else if let Some(body_id) = body_id { s.ann.nested(s, Nested::BodyParamPat(body_id, i)); s.word(":"); s.space(); } if let Some(ty) = ty { s.print_type(ty); } } i += 1; }; self.commasep(Inconsistent, decl.inputs, |s, ty| { let ib = s.ibox(INDENT_UNIT); print_arg(s, Some(ty)); s.end(ib); }); if decl.c_variadic { if !decl.inputs.is_empty() { self.word(", "); } print_arg(self, None); self.word("..."); } self.pclose(); self.print_fn_output(decl); self.print_where_clause(generics) } fn print_closure_params(&mut self, decl: &hir::FnDecl<'_>, body_id: hir::BodyId) { self.word("|"); let mut i = 0; self.commasep(Inconsistent, decl.inputs, |s, ty| { let ib = s.ibox(INDENT_UNIT); s.ann.nested(s, Nested::BodyParamPat(body_id, i)); i += 1; if let hir::TyKind::Infer(()) = ty.kind { // Print nothing. } else { s.word(":"); s.space(); s.print_type(ty); } s.end(ib); }); self.word("|"); match decl.output { hir::FnRetTy::Return(ty) => { self.space_if_not_bol(); self.word_space("->"); self.print_type(ty); self.maybe_print_comment(ty.span.lo()); } hir::FnRetTy::DefaultReturn(..) => {} } } fn print_capture_clause(&mut self, capture_clause: hir::CaptureBy) { match capture_clause { hir::CaptureBy::Value { .. } => self.word_space("move"), hir::CaptureBy::Use { .. } => self.word_space("use"), hir::CaptureBy::Ref => {} } } fn print_closure_binder( &mut self, binder: hir::ClosureBinder, generic_params: &[GenericParam<'_>], ) { let generic_params = generic_params .iter() .filter(|p| { matches!( p, GenericParam { kind: GenericParamKind::Lifetime { kind: LifetimeParamKind::Explicit }, .. } ) }) .collect::>(); match binder { hir::ClosureBinder::Default => {} // We need to distinguish `|...| {}` from `for<> |...| {}` as `for<>` adds additional // restrictions. hir::ClosureBinder::For { .. } if generic_params.is_empty() => self.word("for<>"), hir::ClosureBinder::For { .. } => { self.word("for"); self.word("<"); self.commasep(Inconsistent, &generic_params, |s, param| { s.print_generic_param(param) }); self.word(">"); self.nbsp(); } } } fn print_bounds<'b>( &mut self, prefix: &'static str, bounds: impl IntoIterator>, ) { let mut first = true; for bound in bounds { if first { self.word(prefix); } if !(first && prefix.is_empty()) { self.nbsp(); } if first { first = false; } else { self.word_space("+"); } match bound { GenericBound::Trait(tref) => { self.print_poly_trait_ref(tref); } GenericBound::Outlives(lt) => { self.print_lifetime(lt); } GenericBound::Use(args, _) => { self.word("use <"); self.commasep(Inconsistent, *args, |s, arg| { s.print_precise_capturing_arg(*arg) }); self.word(">"); } } } } fn print_precise_capturing_arg(&mut self, arg: PreciseCapturingArg<'_>) { match arg { PreciseCapturingArg::Lifetime(lt) => self.print_lifetime(lt), PreciseCapturingArg::Param(arg) => self.print_ident(arg.ident), } } fn print_generic_params(&mut self, generic_params: &[GenericParam<'_>]) { let is_lifetime_elided = |generic_param: &GenericParam<'_>| { matches!( generic_param.kind, GenericParamKind::Lifetime { kind: LifetimeParamKind::Elided(_) } ) }; // We don't want to show elided lifetimes as they are compiler-inserted and not // expressible in surface level Rust. if !generic_params.is_empty() && !generic_params.iter().all(is_lifetime_elided) { self.word("<"); self.commasep( Inconsistent, generic_params.iter().filter(|gp| !is_lifetime_elided(gp)), |s, param| s.print_generic_param(param), ); self.word(">"); } } fn print_generic_param(&mut self, param: &GenericParam<'_>) { if let GenericParamKind::Const { .. } = param.kind { self.word_space("const"); } self.print_ident(param.name.ident()); match param.kind { GenericParamKind::Lifetime { .. } => {} GenericParamKind::Type { default, .. } => { if let Some(default) = default { self.space(); self.word_space("="); self.print_type(default); } } GenericParamKind::Const { ty, ref default, synthetic: _ } => { self.word_space(":"); self.print_type(ty); if let Some(default) = default { self.space(); self.word_space("="); self.print_const_arg(default); } } } } fn print_lifetime(&mut self, lifetime: &hir::Lifetime) { self.print_ident(lifetime.ident) } fn print_where_clause(&mut self, generics: &hir::Generics<'_>) { if generics.predicates.is_empty() { return; } self.space(); self.word_space("where"); for (i, predicate) in generics.predicates.iter().enumerate() { if i != 0 { self.word_space(","); } self.print_where_predicate(predicate); } } fn print_where_predicate(&mut self, predicate: &hir::WherePredicate<'_>) { self.print_attrs(self.attrs(predicate.hir_id)); match *predicate.kind { hir::WherePredicateKind::BoundPredicate(hir::WhereBoundPredicate { bound_generic_params, bounded_ty, bounds, .. }) => { self.print_formal_generic_params(bound_generic_params); self.print_type(bounded_ty); self.print_bounds(":", bounds); } hir::WherePredicateKind::RegionPredicate(hir::WhereRegionPredicate { lifetime, bounds, .. }) => { self.print_lifetime(lifetime); self.word(":"); for (i, bound) in bounds.iter().enumerate() { match bound { GenericBound::Outlives(lt) => { self.print_lifetime(lt); } _ => panic!("unexpected bound on lifetime param: {bound:?}"), } if i != 0 { self.word(":"); } } } hir::WherePredicateKind::EqPredicate(hir::WhereEqPredicate { lhs_ty, rhs_ty, .. }) => { self.print_type(lhs_ty); self.space(); self.word_space("="); self.print_type(rhs_ty); } } } fn print_mutability(&mut self, mutbl: hir::Mutability, print_const: bool) { match mutbl { hir::Mutability::Mut => self.word_nbsp("mut"), hir::Mutability::Not => { if print_const { self.word_nbsp("const") } } } } fn print_mt(&mut self, mt: &hir::MutTy<'_>, print_const: bool) { self.print_mutability(mt.mutbl, print_const); self.print_type(mt.ty); } fn print_fn_output(&mut self, decl: &hir::FnDecl<'_>) { match decl.output { hir::FnRetTy::Return(ty) => { self.space_if_not_bol(); let ib = self.ibox(INDENT_UNIT); self.word_space("->"); self.print_type(ty); self.end(ib); if let hir::FnRetTy::Return(output) = decl.output { self.maybe_print_comment(output.span.lo()); } } hir::FnRetTy::DefaultReturn(..) => {} } } fn print_ty_fn( &mut self, abi: ExternAbi, safety: hir::Safety, decl: &hir::FnDecl<'_>, name: Option, generic_params: &[hir::GenericParam<'_>], arg_idents: &[Option], ) { let ib = self.ibox(INDENT_UNIT); self.print_formal_generic_params(generic_params); let generics = hir::Generics::empty(); self.print_fn( hir::FnHeader { safety: safety.into(), abi, constness: hir::Constness::NotConst, asyncness: hir::IsAsync::NotAsync, }, name, generics, decl, arg_idents, None, ); self.end(ib); } fn print_fn_header_info(&mut self, header: hir::FnHeader) { self.print_constness(header.constness); let safety = match header.safety { hir::HeaderSafety::SafeTargetFeatures => { self.word_nbsp("#[target_feature]"); hir::Safety::Safe } hir::HeaderSafety::Normal(safety) => safety, }; match header.asyncness { hir::IsAsync::NotAsync => {} hir::IsAsync::Async(_) => self.word_nbsp("async"), } self.print_safety(safety); if header.abi != ExternAbi::Rust { self.word_nbsp("extern"); self.word_nbsp(header.abi.to_string()); } self.word("fn") } fn print_constness(&mut self, s: hir::Constness) { match s { hir::Constness::NotConst => {} hir::Constness::Const => self.word_nbsp("const"), } } fn print_safety(&mut self, s: hir::Safety) { match s { hir::Safety::Safe => {} hir::Safety::Unsafe => self.word_nbsp("unsafe"), } } fn print_is_auto(&mut self, s: hir::IsAuto) { match s { hir::IsAuto::Yes => self.word_nbsp("auto"), hir::IsAuto::No => {} } } } /// Does this expression require a semicolon to be treated /// as a statement? The negation of this: 'can this expression /// be used as a statement without a semicolon' -- is used /// as an early-bail-out in the parser so that, for instance, /// if true {...} else {...} /// |x| 5 /// isn't parsed as (if true {...} else {...} | x) | 5 // // Duplicated from `parse::classify`, but adapted for the HIR. fn expr_requires_semi_to_be_stmt(e: &hir::Expr<'_>) -> bool { !matches!( e.kind, hir::ExprKind::If(..) | hir::ExprKind::Match(..) | hir::ExprKind::Block(..) | hir::ExprKind::Loop(..) ) } /// This statement requires a semicolon after it. /// note that in one case (stmt_semi), we've already /// seen the semicolon, and thus don't need another. fn stmt_ends_with_semi(stmt: &hir::StmtKind<'_>) -> bool { match *stmt { hir::StmtKind::Let(_) => true, hir::StmtKind::Item(_) => false, hir::StmtKind::Expr(e) => expr_requires_semi_to_be_stmt(e), hir::StmtKind::Semi(..) => false, } } /// Expressions that syntactically contain an "exterior" struct literal, i.e., not surrounded by any /// parens or other delimiters, e.g., `X { y: 1 }`, `X { y: 1 }.method()`, `foo == X { y: 1 }` and /// `X { y: 1 } == foo` all do, but `(X { y: 1 }) == foo` does not. fn contains_exterior_struct_lit(value: &hir::Expr<'_>) -> bool { match value.kind { hir::ExprKind::Struct(..) => true, hir::ExprKind::Assign(lhs, rhs, _) | hir::ExprKind::AssignOp(_, lhs, rhs) | hir::ExprKind::Binary(_, lhs, rhs) => { // `X { y: 1 } + X { y: 2 }` contains_exterior_struct_lit(lhs) || contains_exterior_struct_lit(rhs) } hir::ExprKind::Unary(_, x) | hir::ExprKind::Cast(x, _) | hir::ExprKind::Type(x, _) | hir::ExprKind::Field(x, _) | hir::ExprKind::Index(x, _, _) => { // `&X { y: 1 }, X { y: 1 }.y` contains_exterior_struct_lit(x) } hir::ExprKind::MethodCall(_, receiver, ..) => { // `X { y: 1 }.bar(...)` contains_exterior_struct_lit(receiver) } _ => false, } }