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rust/rust/573bd7d4ada3677648942e644f0894de7d22ac14/./compiler/rustc_hir_pretty/src/lib.rs
blob: 136fe22eea60fd0ed349bfbb5cb51e76ab8307e7 [file]
//! 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 as ast;
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 as hir;
use rustc_hir::attrs::{AttributeKind, PrintAttribute};
use rustc_hir::{
BindingMode, ByRef, ConstArg, ConstArgExprField, ConstArgKind, GenericArg, GenericBound,
GenericParam, GenericParamKind, HirId, ImplicitSelfKind, LifetimeParamKind, Node, PatKind,
PreciseCapturingArg, RangeEnd, Term, TyFieldPath, TyPatKind,
};
use rustc_span::source_map::SourceMap;
use rustc_span::{DUMMY_SP, FileName, Ident, Span, Spanned, Symbol, kw, sym};
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<Comments<'a>>,
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: Ident { name: *i, span: DUMMY_SP },
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),
// FIXME(mgca): proper printing for struct exprs
Node::ConstArgExprField(_) => self.word("/* STRUCT EXPR */"),
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<F>(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<BoxMarker>) {
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<T, F, G>(&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::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);
}
hir::TyKind::FieldOf(ty, TyFieldPath { variant, field }) => {
self.word("field_of!(");
self.print_type(ty);
self.word(", ");
if let Some(variant) = *variant {
self.print_ident(variant);
self.word(".");
}
self.print_ident(*field);
self.word(")");
}
}
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<hir::ConstItemRhs<'_>>,
) {
self.word_space("const");
self.print_ident(ident);
self.print_generic_params(generics.params);
self.word_space(":");
self.print_type(ty);
if let Some(ct_rhs) = default {
self.space();
self.word_space("=");
self.print_const_item_rhs(ct_rhs);
}
self.print_where_clause(generics);
self.word(";")
}
fn print_associated_type(
&mut self,
ident: Ident,
generics: &hir::Generics<'_>,
bounds: Option<hir::GenericBounds<'_>>,
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, rhs) => {
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.print_const_item_rhs(rhs);
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 { generics, of_trait, self_ty, items, constness }) => {
let (cb, ib) = self.head("");
let impl_generics = |this: &mut Self| {
this.word_nbsp("impl");
if !generics.params.is_empty() {
this.print_generic_params(generics.params);
this.space();
}
};
match of_trait {
None => {
if let hir::Constness::Const { always: false } = constness {
self.word_nbsp("const");
}
impl_generics(self)
}
Some(&hir::TraitImplHeader {
safety,
polarity,
defaultness,
defaultness_span: _,
ref trait_ref,
}) => {
self.print_defaultness(defaultness);
self.print_safety(safety);
impl_generics(self);
if let hir::Constness::Const { always: false } = constness {
self.word_nbsp("const");
}
if let hir::ImplPolarity::Negative(_) = polarity {
self.word("!");
}
self.print_trait_ref(trait_ref);
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 {
impl_restriction,
constness,
is_auto,
safety,
ident,
generics,
bounds,
items: trait_items,
} => {
let (cb, ib) = self.head("");
self.print_impl_restriction(impl_restriction);
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(constness, ident, generics, bounds) => {
let (cb, ib) = self.head("");
self.print_constness(constness);
self.word_nbsp("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<Ident>],
body_id: Option<hir::BodyId>,
) {
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<BoxMarker>,
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_item_rhs(&mut self, ct_rhs: hir::ConstItemRhs<'_>) {
match ct_rhs {
hir::ConstItemRhs::Body(body_id) => self.ann.nested(self, Nested::Body(body_id)),
hir::ConstItemRhs::TypeConst(const_arg) => self.print_const_arg(const_arg),
}
}
fn print_const_arg(&mut self, const_arg: &hir::ConstArg<'_>) {
match &const_arg.kind {
ConstArgKind::Tup(exprs) => {
self.popen();
self.commasep_cmnt(
Inconsistent,
exprs,
|s, arg| s.print_const_arg(arg),
|arg| arg.span,
);
self.pclose();
}
ConstArgKind::Struct(qpath, fields) => self.print_const_struct(qpath, fields),
ConstArgKind::TupleCall(qpath, args) => self.print_const_ctor(qpath, args),
ConstArgKind::Array(..) => self.word("/* ARRAY EXPR */"),
ConstArgKind::Path(qpath) => self.print_qpath(qpath, true),
ConstArgKind::Anon(anon) => self.print_anon_const(anon),
ConstArgKind::Error(_) => self.word("/*ERROR*/"),
ConstArgKind::Infer(..) => self.word("_"),
ConstArgKind::Literal { lit, negated } => {
if *negated {
self.word("-");
}
let span = const_arg.span;
self.print_literal(&Spanned { span, node: *lit })
}
}
}
fn print_const_struct(&mut self, qpath: &hir::QPath<'_>, fields: &&[&ConstArgExprField<'_>]) {
self.print_qpath(qpath, true);
self.word(" ");
self.word("{");
if !fields.is_empty() {
self.nbsp();
}
self.commasep(Inconsistent, *fields, |s, field| {
s.word(field.field.as_str().to_string());
s.word(":");
s.nbsp();
s.print_const_arg(field.expr);
});
self.word("}");
}
fn print_const_ctor(&mut self, qpath: &hir::QPath<'_>, args: &&[&ConstArg<'_, ()>]) {
self.print_qpath(qpath, true);
self.word("(");
self.commasep(Inconsistent, *args, |s, arg| {
s.print_const_arg(arg);
});
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 => {}
hir::StructTailExpr::NoneWithError(_) => {}
}
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: _,
explicit_captures: _,
}) => {
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<R>(&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 `<<A::B>::C>` as `<A::B>::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)
}
}
}
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::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::NotNull => {
self.word_space("not");
self.word("null");
}
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(pinnedness, rmutbl) = by_ref {
self.word_nbsp("ref");
if pinnedness.is_pinned() {
self.word_nbsp("pin");
}
if rmutbl.is_mut() {
self.word_nbsp("mut");
} else if pinnedness.is_pinned() {
self.word_nbsp("const");
}
}
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.is_none();
if !empty {
self.space();
}
self.commasep_cmnt(Consistent, fields, |s, f| s.print_patfield(f), |f| f.pat.span);
if etc.is_some() {
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, pinned, mutbl) => {
let is_range_inner = matches!(inner.kind, PatKind::Range(..));
self.word("&");
if pinned.is_pinned() {
self.word("pin ");
if mutbl.is_not() {
self.word("const ");
}
}
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<Symbol>,
generics: &hir::Generics<'_>,
decl: &hir::FnDecl<'_>,
arg_idents: &[Option<Ident>],
body_id: Option<hir::BodyId>,
) {
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 Some(i) == decl.splatted().map(usize::from) {
s.word("#[splat]");
}
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::<Vec<_>>();
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<Item = &'b hir::GenericBound<'b>>,
) {
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 } => {
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(":");
}
}
}
}
}
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<Symbol>,
generic_params: &[hir::GenericParam<'_>],
arg_idents: &[Option<Ident>],
) {
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 { always: false } => self.word_nbsp("const"),
hir::Constness::Const { always: true } => { /* printed as an attribute */ }
}
}
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 => {}
}
}
fn print_impl_restriction(&mut self, r: &hir::ImplRestriction<'_>) {
match r.kind {
hir::RestrictionKind::Unrestricted => {}
hir::RestrictionKind::Restricted(path) => {
self.word("impl(");
self.word_nbsp("in");
self.print_path(path, false);
self.word(")");
}
}
}
}
/// 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,
}
}