rust/crates/hir_ty/src/display.rs
2021-12-07 17:31:26 +01:00

1235 lines
47 KiB
Rust

//! The `HirDisplay` trait, which serves two purposes: Turning various bits from
//! HIR back into source code, and just displaying them for debugging/testing
//! purposes.
use std::fmt::{self, Debug};
use base_db::CrateId;
use chalk_ir::BoundVar;
use hir_def::{
body,
db::DefDatabase,
find_path,
generics::TypeParamProvenance,
intern::{Internable, Interned},
item_scope::ItemInNs,
path::{Path, PathKind},
type_ref::{TraitBoundModifier, TypeBound, TypeRef},
visibility::Visibility,
HasModule, ItemContainerId, Lookup, ModuleId, TraitId,
};
use hir_expand::{hygiene::Hygiene, name::Name};
use itertools::Itertools;
use crate::{
const_from_placeholder_idx,
db::HirDatabase,
from_assoc_type_id, from_foreign_def_id, from_placeholder_idx, lt_from_placeholder_idx,
mapping::from_chalk,
primitive, subst_prefix, to_assoc_type_id,
utils::{self, generics},
AdtId, AliasEq, AliasTy, CallableDefId, CallableSig, Const, ConstValue, DomainGoal, GenericArg,
ImplTraitId, Interner, Lifetime, LifetimeData, LifetimeOutlives, Mutability, OpaqueTy,
ProjectionTy, ProjectionTyExt, QuantifiedWhereClause, Scalar, TraitRef, TraitRefExt, Ty, TyExt,
TyKind, WhereClause,
};
pub struct HirFormatter<'a> {
pub db: &'a dyn HirDatabase,
fmt: &'a mut dyn fmt::Write,
buf: String,
curr_size: usize,
pub(crate) max_size: Option<usize>,
omit_verbose_types: bool,
display_target: DisplayTarget,
}
pub trait HirDisplay {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError>;
/// Returns a `Display`able type that is human-readable.
fn into_displayable<'a>(
&'a self,
db: &'a dyn HirDatabase,
max_size: Option<usize>,
omit_verbose_types: bool,
display_target: DisplayTarget,
) -> HirDisplayWrapper<'a, Self>
where
Self: Sized,
{
assert!(
!matches!(display_target, DisplayTarget::SourceCode { .. }),
"HirDisplayWrapper cannot fail with DisplaySourceCodeError, use HirDisplay::hir_fmt directly instead"
);
HirDisplayWrapper { db, t: self, max_size, omit_verbose_types, display_target }
}
/// Returns a `Display`able type that is human-readable.
/// Use this for showing types to the user (e.g. diagnostics)
fn display<'a>(&'a self, db: &'a dyn HirDatabase) -> HirDisplayWrapper<'a, Self>
where
Self: Sized,
{
HirDisplayWrapper {
db,
t: self,
max_size: None,
omit_verbose_types: false,
display_target: DisplayTarget::Diagnostics,
}
}
/// Returns a `Display`able type that is human-readable and tries to be succinct.
/// Use this for showing types to the user where space is constrained (e.g. doc popups)
fn display_truncated<'a>(
&'a self,
db: &'a dyn HirDatabase,
max_size: Option<usize>,
) -> HirDisplayWrapper<'a, Self>
where
Self: Sized,
{
HirDisplayWrapper {
db,
t: self,
max_size,
omit_verbose_types: true,
display_target: DisplayTarget::Diagnostics,
}
}
/// Returns a String representation of `self` that can be inserted into the given module.
/// Use this when generating code (e.g. assists)
fn display_source_code<'a>(
&'a self,
db: &'a dyn HirDatabase,
module_id: ModuleId,
) -> Result<String, DisplaySourceCodeError> {
let mut result = String::new();
match self.hir_fmt(&mut HirFormatter {
db,
fmt: &mut result,
buf: String::with_capacity(20),
curr_size: 0,
max_size: None,
omit_verbose_types: false,
display_target: DisplayTarget::SourceCode { module_id },
}) {
Ok(()) => {}
Err(HirDisplayError::FmtError) => panic!("Writing to String can't fail!"),
Err(HirDisplayError::DisplaySourceCodeError(e)) => return Err(e),
};
Ok(result)
}
/// Returns a String representation of `self` for test purposes
fn display_test<'a>(&'a self, db: &'a dyn HirDatabase) -> HirDisplayWrapper<'a, Self>
where
Self: Sized,
{
HirDisplayWrapper {
db,
t: self,
max_size: None,
omit_verbose_types: false,
display_target: DisplayTarget::Test,
}
}
}
impl<'a> HirFormatter<'a> {
pub fn write_joined<T: HirDisplay>(
&mut self,
iter: impl IntoIterator<Item = T>,
sep: &str,
) -> Result<(), HirDisplayError> {
let mut first = true;
for e in iter {
if !first {
write!(self, "{}", sep)?;
}
first = false;
e.hir_fmt(self)?;
}
Ok(())
}
/// This allows using the `write!` macro directly with a `HirFormatter`.
pub fn write_fmt(&mut self, args: fmt::Arguments) -> Result<(), HirDisplayError> {
// We write to a buffer first to track output size
self.buf.clear();
fmt::write(&mut self.buf, args)?;
self.curr_size += self.buf.len();
// Then we write to the internal formatter from the buffer
self.fmt.write_str(&self.buf).map_err(HirDisplayError::from)
}
pub fn should_truncate(&self) -> bool {
match self.max_size {
Some(max_size) => self.curr_size >= max_size,
None => false,
}
}
pub fn omit_verbose_types(&self) -> bool {
self.omit_verbose_types
}
}
#[derive(Clone, Copy)]
pub enum DisplayTarget {
/// Display types for inlays, doc popups, autocompletion, etc...
/// Showing `{unknown}` or not qualifying paths is fine here.
/// There's no reason for this to fail.
Diagnostics,
/// Display types for inserting them in source files.
/// The generated code should compile, so paths need to be qualified.
SourceCode { module_id: ModuleId },
/// Only for test purpose to keep real types
Test,
}
impl DisplayTarget {
fn is_source_code(&self) -> bool {
matches!(self, Self::SourceCode { .. })
}
fn is_test(&self) -> bool {
matches!(self, Self::Test)
}
}
#[derive(Debug)]
pub enum DisplaySourceCodeError {
PathNotFound,
UnknownType,
Closure,
}
pub enum HirDisplayError {
/// Errors that can occur when generating source code
DisplaySourceCodeError(DisplaySourceCodeError),
/// `FmtError` is required to be compatible with std::fmt::Display
FmtError,
}
impl From<fmt::Error> for HirDisplayError {
fn from(_: fmt::Error) -> Self {
Self::FmtError
}
}
pub struct HirDisplayWrapper<'a, T> {
db: &'a dyn HirDatabase,
t: &'a T,
max_size: Option<usize>,
omit_verbose_types: bool,
display_target: DisplayTarget,
}
impl<'a, T> fmt::Display for HirDisplayWrapper<'a, T>
where
T: HirDisplay,
{
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self.t.hir_fmt(&mut HirFormatter {
db: self.db,
fmt: f,
buf: String::with_capacity(20),
curr_size: 0,
max_size: self.max_size,
omit_verbose_types: self.omit_verbose_types,
display_target: self.display_target,
}) {
Ok(()) => Ok(()),
Err(HirDisplayError::FmtError) => Err(fmt::Error),
Err(HirDisplayError::DisplaySourceCodeError(_)) => {
// This should never happen
panic!("HirDisplay::hir_fmt failed with DisplaySourceCodeError when calling Display::fmt!")
}
}
}
}
const TYPE_HINT_TRUNCATION: &str = "";
impl<T: HirDisplay> HirDisplay for &'_ T {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
HirDisplay::hir_fmt(*self, f)
}
}
impl<T: HirDisplay + Internable> HirDisplay for Interned<T> {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
HirDisplay::hir_fmt(self.as_ref(), f)
}
}
impl HirDisplay for ProjectionTy {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
if f.should_truncate() {
return write!(f, "{}", TYPE_HINT_TRUNCATION);
}
let trait_ = f.db.trait_data(self.trait_(f.db));
write!(f, "<")?;
self.self_type_parameter(&Interner).hir_fmt(f)?;
write!(f, " as {}", trait_.name)?;
if self.substitution.len(&Interner) > 1 {
write!(f, "<")?;
f.write_joined(&self.substitution.as_slice(&Interner)[1..], ", ")?;
write!(f, ">")?;
}
write!(f, ">::{}", f.db.type_alias_data(from_assoc_type_id(self.associated_ty_id)).name)?;
Ok(())
}
}
impl HirDisplay for OpaqueTy {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
if f.should_truncate() {
return write!(f, "{}", TYPE_HINT_TRUNCATION);
}
self.substitution.at(&Interner, 0).hir_fmt(f)
}
}
impl HirDisplay for GenericArg {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
match self.interned() {
crate::GenericArgData::Ty(ty) => ty.hir_fmt(f),
crate::GenericArgData::Lifetime(lt) => lt.hir_fmt(f),
crate::GenericArgData::Const(c) => c.hir_fmt(f),
}
}
}
impl HirDisplay for Const {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
let data = self.interned();
match data.value {
ConstValue::BoundVar(idx) => idx.hir_fmt(f),
ConstValue::InferenceVar(..) => write!(f, "_"),
ConstValue::Placeholder(idx) => {
let id = const_from_placeholder_idx(f.db, idx);
let generics = generics(f.db.upcast(), id.parent);
let param_data = &generics.params.consts[id.local_id];
write!(f, "{}", param_data.name)
}
ConstValue::Concrete(c) => write!(f, "{}", c.interned),
}
}
}
impl HirDisplay for BoundVar {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
write!(f, "?{}.{}", self.debruijn.depth(), self.index)
}
}
impl HirDisplay for Ty {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
if f.should_truncate() {
return write!(f, "{}", TYPE_HINT_TRUNCATION);
}
match self.kind(&Interner) {
TyKind::Never => write!(f, "!")?,
TyKind::Str => write!(f, "str")?,
TyKind::Scalar(Scalar::Bool) => write!(f, "bool")?,
TyKind::Scalar(Scalar::Char) => write!(f, "char")?,
&TyKind::Scalar(Scalar::Float(t)) => write!(f, "{}", primitive::float_ty_to_string(t))?,
&TyKind::Scalar(Scalar::Int(t)) => write!(f, "{}", primitive::int_ty_to_string(t))?,
&TyKind::Scalar(Scalar::Uint(t)) => write!(f, "{}", primitive::uint_ty_to_string(t))?,
TyKind::Slice(t) => {
write!(f, "[")?;
t.hir_fmt(f)?;
write!(f, "]")?;
}
TyKind::Array(t, c) => {
write!(f, "[")?;
t.hir_fmt(f)?;
write!(f, "; ")?;
c.hir_fmt(f)?;
write!(f, "]")?;
}
TyKind::Raw(m, t) | TyKind::Ref(m, _, t) => {
if matches!(self.kind(&Interner), TyKind::Raw(..)) {
write!(
f,
"*{}",
match m {
Mutability::Not => "const ",
Mutability::Mut => "mut ",
}
)?;
} else {
write!(
f,
"&{}",
match m {
Mutability::Not => "",
Mutability::Mut => "mut ",
}
)?;
}
// FIXME: all this just to decide whether to use parentheses...
let contains_impl_fn = |bounds: &[QuantifiedWhereClause]| {
bounds.iter().any(|bound| {
if let WhereClause::Implemented(trait_ref) = bound.skip_binders() {
let trait_ = trait_ref.hir_trait_id();
fn_traits(f.db.upcast(), trait_).any(|it| it == trait_)
} else {
false
}
})
};
let (preds_to_print, has_impl_fn_pred) = match t.kind(&Interner) {
TyKind::Dyn(dyn_ty) if dyn_ty.bounds.skip_binders().interned().len() > 1 => {
let bounds = dyn_ty.bounds.skip_binders().interned();
(bounds.len(), contains_impl_fn(bounds))
}
TyKind::Alias(AliasTy::Opaque(OpaqueTy {
opaque_ty_id,
substitution: parameters,
}))
| TyKind::OpaqueType(opaque_ty_id, parameters) => {
let impl_trait_id =
f.db.lookup_intern_impl_trait_id((*opaque_ty_id).into());
if let ImplTraitId::ReturnTypeImplTrait(func, idx) = impl_trait_id {
let datas =
f.db.return_type_impl_traits(func)
.expect("impl trait id without data");
let data = (*datas)
.as_ref()
.map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
let bounds = data.substitute(&Interner, parameters);
let mut len = bounds.skip_binders().len();
// Don't count Sized but count when it absent
// (i.e. when explicit ?Sized bound is set).
let default_sized = SizedByDefault::Sized {
anchor: func.lookup(f.db.upcast()).module(f.db.upcast()).krate(),
};
let sized_bounds = bounds
.skip_binders()
.iter()
.filter(|b| {
matches!(
b.skip_binders(),
WhereClause::Implemented(trait_ref)
if default_sized.is_sized_trait(
trait_ref.hir_trait_id(),
f.db.upcast(),
),
)
})
.count();
match sized_bounds {
0 => len += 1,
_ => {
len = len.saturating_sub(sized_bounds);
}
}
(len, contains_impl_fn(bounds.skip_binders()))
} else {
(0, false)
}
}
_ => (0, false),
};
if has_impl_fn_pred && preds_to_print <= 2 {
return t.hir_fmt(f);
}
if preds_to_print > 1 {
write!(f, "(")?;
t.hir_fmt(f)?;
write!(f, ")")?;
} else {
t.hir_fmt(f)?;
}
}
TyKind::Tuple(_, substs) => {
if substs.len(&Interner) == 1 {
write!(f, "(")?;
substs.at(&Interner, 0).hir_fmt(f)?;
write!(f, ",)")?;
} else {
write!(f, "(")?;
f.write_joined(&*substs.as_slice(&Interner), ", ")?;
write!(f, ")")?;
}
}
TyKind::Function(fn_ptr) => {
let sig = CallableSig::from_fn_ptr(fn_ptr);
sig.hir_fmt(f)?;
}
TyKind::FnDef(def, parameters) => {
let def = from_chalk(f.db, *def);
let sig = f.db.callable_item_signature(def).substitute(&Interner, parameters);
match def {
CallableDefId::FunctionId(ff) => {
write!(f, "fn {}", f.db.function_data(ff).name)?
}
CallableDefId::StructId(s) => write!(f, "{}", f.db.struct_data(s).name)?,
CallableDefId::EnumVariantId(e) => {
write!(f, "{}", f.db.enum_data(e.parent).variants[e.local_id].name)?
}
};
if parameters.len(&Interner) > 0 {
let generics = generics(f.db.upcast(), def.into());
let (parent_params, self_param, type_params, _impl_trait_params) =
generics.provenance_split();
let total_len = parent_params + self_param + type_params;
// We print all params except implicit impl Trait params. Still a bit weird; should we leave out parent and self?
if total_len > 0 {
write!(f, "<")?;
f.write_joined(&parameters.as_slice(&Interner)[..total_len], ", ")?;
write!(f, ">")?;
}
}
write!(f, "(")?;
f.write_joined(sig.params(), ", ")?;
write!(f, ")")?;
let ret = sig.ret();
if !ret.is_unit() {
write!(f, " -> ")?;
ret.hir_fmt(f)?;
}
}
TyKind::Adt(AdtId(def_id), parameters) => {
match f.display_target {
DisplayTarget::Diagnostics | DisplayTarget::Test => {
let name = match *def_id {
hir_def::AdtId::StructId(it) => f.db.struct_data(it).name.clone(),
hir_def::AdtId::UnionId(it) => f.db.union_data(it).name.clone(),
hir_def::AdtId::EnumId(it) => f.db.enum_data(it).name.clone(),
};
write!(f, "{}", name)?;
}
DisplayTarget::SourceCode { module_id } => {
if let Some(path) = find_path::find_path(
f.db.upcast(),
ItemInNs::Types((*def_id).into()),
module_id,
) {
write!(f, "{}", path)?;
} else {
return Err(HirDisplayError::DisplaySourceCodeError(
DisplaySourceCodeError::PathNotFound,
));
}
}
}
if parameters.len(&Interner) > 0 {
let parameters_to_write = if f.display_target.is_source_code()
|| f.omit_verbose_types()
{
match self
.as_generic_def(f.db)
.map(|generic_def_id| f.db.generic_defaults(generic_def_id))
.filter(|defaults| !defaults.is_empty())
{
None => parameters.as_slice(&Interner),
Some(default_parameters) => {
let mut default_from = 0;
for (i, parameter) in parameters.iter(&Interner).enumerate() {
match (
parameter.assert_ty_ref(&Interner).kind(&Interner),
default_parameters.get(i),
) {
(&TyKind::Error, _) | (_, None) => {
default_from = i + 1;
}
(_, Some(default_parameter)) => {
let actual_default =
default_parameter.clone().substitute(
&Interner,
&subst_prefix(parameters, i),
);
if parameter.assert_ty_ref(&Interner) != &actual_default
{
default_from = i + 1;
}
}
}
}
&parameters.as_slice(&Interner)[0..default_from]
}
}
} else {
parameters.as_slice(&Interner)
};
if !parameters_to_write.is_empty() {
write!(f, "<")?;
f.write_joined(parameters_to_write, ", ")?;
write!(f, ">")?;
}
}
}
TyKind::AssociatedType(assoc_type_id, parameters) => {
let type_alias = from_assoc_type_id(*assoc_type_id);
let trait_ = match type_alias.lookup(f.db.upcast()).container {
ItemContainerId::TraitId(it) => it,
_ => panic!("not an associated type"),
};
let trait_ = f.db.trait_data(trait_);
let type_alias_data = f.db.type_alias_data(type_alias);
// Use placeholder associated types when the target is test (https://rust-lang.github.io/chalk/book/clauses/type_equality.html#placeholder-associated-types)
if f.display_target.is_test() {
write!(f, "{}::{}", trait_.name, type_alias_data.name)?;
if parameters.len(&Interner) > 0 {
write!(f, "<")?;
f.write_joined(&*parameters.as_slice(&Interner), ", ")?;
write!(f, ">")?;
}
} else {
let projection_ty = ProjectionTy {
associated_ty_id: to_assoc_type_id(type_alias),
substitution: parameters.clone(),
};
projection_ty.hir_fmt(f)?;
}
}
TyKind::Foreign(type_alias) => {
let type_alias = f.db.type_alias_data(from_foreign_def_id(*type_alias));
write!(f, "{}", type_alias.name)?;
}
TyKind::OpaqueType(opaque_ty_id, parameters) => {
let impl_trait_id = f.db.lookup_intern_impl_trait_id((*opaque_ty_id).into());
match impl_trait_id {
ImplTraitId::ReturnTypeImplTrait(func, idx) => {
let datas =
f.db.return_type_impl_traits(func).expect("impl trait id without data");
let data = (*datas)
.as_ref()
.map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
let bounds = data.substitute(&Interner, &parameters);
let krate = func.lookup(f.db.upcast()).module(f.db.upcast()).krate();
write_bounds_like_dyn_trait_with_prefix(
"impl",
bounds.skip_binders(),
SizedByDefault::Sized { anchor: krate },
f,
)?;
// FIXME: it would maybe be good to distinguish this from the alias type (when debug printing), and to show the substitution
}
ImplTraitId::AsyncBlockTypeImplTrait(..) => {
write!(f, "impl Future<Output = ")?;
parameters.at(&Interner, 0).hir_fmt(f)?;
write!(f, ">")?;
}
}
}
TyKind::Closure(.., substs) => {
if f.display_target.is_source_code() {
return Err(HirDisplayError::DisplaySourceCodeError(
DisplaySourceCodeError::Closure,
));
}
let sig = substs.at(&Interner, 0).assert_ty_ref(&Interner).callable_sig(f.db);
if let Some(sig) = sig {
if sig.params().is_empty() {
write!(f, "||")?;
} else if f.should_truncate() {
write!(f, "|{}|", TYPE_HINT_TRUNCATION)?;
} else {
write!(f, "|")?;
f.write_joined(sig.params(), ", ")?;
write!(f, "|")?;
};
write!(f, " -> ")?;
sig.ret().hir_fmt(f)?;
} else {
write!(f, "{{closure}}")?;
}
}
TyKind::Placeholder(idx) => {
let id = from_placeholder_idx(f.db, *idx);
let generics = generics(f.db.upcast(), id.parent);
let param_data = &generics.params.types[id.local_id];
match param_data.provenance {
TypeParamProvenance::TypeParamList | TypeParamProvenance::TraitSelf => {
write!(f, "{}", param_data.name.clone().unwrap_or_else(Name::missing))?
}
TypeParamProvenance::ArgumentImplTrait => {
let substs = generics.type_params_subst(f.db);
let bounds =
f.db.generic_predicates(id.parent)
.iter()
.map(|pred| pred.clone().substitute(&Interner, &substs))
.filter(|wc| match &wc.skip_binders() {
WhereClause::Implemented(tr) => {
&tr.self_type_parameter(&Interner) == self
}
WhereClause::AliasEq(AliasEq {
alias: AliasTy::Projection(proj),
ty: _,
}) => &proj.self_type_parameter(&Interner) == self,
_ => false,
})
.collect::<Vec<_>>();
let krate = id.parent.module(f.db.upcast()).krate();
write_bounds_like_dyn_trait_with_prefix(
"impl",
&bounds,
SizedByDefault::Sized { anchor: krate },
f,
)?;
}
}
}
TyKind::BoundVar(idx) => idx.hir_fmt(f)?,
TyKind::Dyn(dyn_ty) => {
write_bounds_like_dyn_trait_with_prefix(
"dyn",
dyn_ty.bounds.skip_binders().interned(),
SizedByDefault::NotSized,
f,
)?;
}
TyKind::Alias(AliasTy::Projection(p_ty)) => p_ty.hir_fmt(f)?,
TyKind::Alias(AliasTy::Opaque(opaque_ty)) => {
let impl_trait_id = f.db.lookup_intern_impl_trait_id(opaque_ty.opaque_ty_id.into());
match impl_trait_id {
ImplTraitId::ReturnTypeImplTrait(func, idx) => {
let datas =
f.db.return_type_impl_traits(func).expect("impl trait id without data");
let data = (*datas)
.as_ref()
.map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
let bounds = data.substitute(&Interner, &opaque_ty.substitution);
let krate = func.lookup(f.db.upcast()).module(f.db.upcast()).krate();
write_bounds_like_dyn_trait_with_prefix(
"impl",
bounds.skip_binders(),
SizedByDefault::Sized { anchor: krate },
f,
)?;
}
ImplTraitId::AsyncBlockTypeImplTrait(..) => {
write!(f, "{{async block}}")?;
}
};
}
TyKind::Error => {
if f.display_target.is_source_code() {
return Err(HirDisplayError::DisplaySourceCodeError(
DisplaySourceCodeError::UnknownType,
));
}
write!(f, "{{unknown}}")?;
}
TyKind::InferenceVar(..) => write!(f, "_")?,
TyKind::Generator(..) => write!(f, "{{generator}}")?,
TyKind::GeneratorWitness(..) => write!(f, "{{generator witness}}")?,
}
Ok(())
}
}
impl HirDisplay for CallableSig {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
write!(f, "fn(")?;
f.write_joined(self.params(), ", ")?;
if self.is_varargs {
if self.params().is_empty() {
write!(f, "...")?;
} else {
write!(f, ", ...")?;
}
}
write!(f, ")")?;
let ret = self.ret();
if !ret.is_unit() {
write!(f, " -> ")?;
ret.hir_fmt(f)?;
}
Ok(())
}
}
fn fn_traits(db: &dyn DefDatabase, trait_: TraitId) -> impl Iterator<Item = TraitId> {
let krate = trait_.lookup(db).container.krate();
utils::fn_traits(db, krate)
}
#[derive(Clone, Copy, PartialEq, Eq)]
pub enum SizedByDefault {
NotSized,
Sized { anchor: CrateId },
}
impl SizedByDefault {
fn is_sized_trait(self, trait_: TraitId, db: &dyn DefDatabase) -> bool {
match self {
Self::NotSized => false,
Self::Sized { anchor } => {
let sized_trait =
db.lang_item(anchor, "sized".into()).and_then(|lang_item| lang_item.as_trait());
Some(trait_) == sized_trait
}
}
}
}
pub fn write_bounds_like_dyn_trait_with_prefix(
prefix: &str,
predicates: &[QuantifiedWhereClause],
default_sized: SizedByDefault,
f: &mut HirFormatter,
) -> Result<(), HirDisplayError> {
write!(f, "{}", prefix)?;
if !predicates.is_empty()
|| predicates.is_empty() && matches!(default_sized, SizedByDefault::Sized { .. })
{
write!(f, " ")?;
write_bounds_like_dyn_trait(predicates, default_sized, f)
} else {
Ok(())
}
}
fn write_bounds_like_dyn_trait(
predicates: &[QuantifiedWhereClause],
default_sized: SizedByDefault,
f: &mut HirFormatter,
) -> Result<(), HirDisplayError> {
// Note: This code is written to produce nice results (i.e.
// corresponding to surface Rust) for types that can occur in
// actual Rust. It will have weird results if the predicates
// aren't as expected (i.e. self types = $0, projection
// predicates for a certain trait come after the Implemented
// predicate for that trait).
let mut first = true;
let mut angle_open = false;
let mut is_fn_trait = false;
let mut is_sized = false;
for p in predicates.iter() {
match p.skip_binders() {
WhereClause::Implemented(trait_ref) => {
let trait_ = trait_ref.hir_trait_id();
if default_sized.is_sized_trait(trait_, f.db.upcast()) {
is_sized = true;
if matches!(default_sized, SizedByDefault::Sized { .. }) {
// Don't print +Sized, but rather +?Sized if absent.
continue;
}
}
if !is_fn_trait {
is_fn_trait = fn_traits(f.db.upcast(), trait_).any(|it| it == trait_);
}
if !is_fn_trait && angle_open {
write!(f, ">")?;
angle_open = false;
}
if !first {
write!(f, " + ")?;
}
// We assume that the self type is ^0.0 (i.e. the
// existential) here, which is the only thing that's
// possible in actual Rust, and hence don't print it
write!(f, "{}", f.db.trait_data(trait_).name)?;
if let [_, params @ ..] = &*trait_ref.substitution.as_slice(&Interner) {
if is_fn_trait {
if let Some(args) =
params.first().and_then(|it| it.assert_ty_ref(&Interner).as_tuple())
{
write!(f, "(")?;
f.write_joined(args.as_slice(&Interner), ", ")?;
write!(f, ")")?;
}
} else if !params.is_empty() {
write!(f, "<")?;
f.write_joined(params, ", ")?;
// there might be assoc type bindings, so we leave the angle brackets open
angle_open = true;
}
}
}
WhereClause::AliasEq(alias_eq) if is_fn_trait => {
is_fn_trait = false;
if !alias_eq.ty.is_unit() {
write!(f, " -> ")?;
alias_eq.ty.hir_fmt(f)?;
}
}
WhereClause::AliasEq(AliasEq { ty, alias }) => {
// in types in actual Rust, these will always come
// after the corresponding Implemented predicate
if angle_open {
write!(f, ", ")?;
} else {
write!(f, "<")?;
angle_open = true;
}
if let AliasTy::Projection(proj) = alias {
let type_alias =
f.db.type_alias_data(from_assoc_type_id(proj.associated_ty_id));
write!(f, "{} = ", type_alias.name)?;
}
ty.hir_fmt(f)?;
}
// FIXME implement these
WhereClause::LifetimeOutlives(_) => {}
WhereClause::TypeOutlives(_) => {}
}
first = false;
}
if angle_open {
write!(f, ">")?;
}
if matches!(default_sized, SizedByDefault::Sized { .. }) {
if !is_sized {
write!(f, "{}?Sized", if first { "" } else { " + " })?;
} else if first {
write!(f, "Sized")?;
}
}
Ok(())
}
fn fmt_trait_ref(tr: &TraitRef, f: &mut HirFormatter, use_as: bool) -> Result<(), HirDisplayError> {
if f.should_truncate() {
return write!(f, "{}", TYPE_HINT_TRUNCATION);
}
tr.self_type_parameter(&Interner).hir_fmt(f)?;
if use_as {
write!(f, " as ")?;
} else {
write!(f, ": ")?;
}
write!(f, "{}", f.db.trait_data(tr.hir_trait_id()).name)?;
if tr.substitution.len(&Interner) > 1 {
write!(f, "<")?;
f.write_joined(&tr.substitution.as_slice(&Interner)[1..], ", ")?;
write!(f, ">")?;
}
Ok(())
}
impl HirDisplay for TraitRef {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
fmt_trait_ref(self, f, false)
}
}
impl HirDisplay for WhereClause {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
if f.should_truncate() {
return write!(f, "{}", TYPE_HINT_TRUNCATION);
}
match self {
WhereClause::Implemented(trait_ref) => trait_ref.hir_fmt(f)?,
WhereClause::AliasEq(AliasEq { alias: AliasTy::Projection(projection_ty), ty }) => {
write!(f, "<")?;
fmt_trait_ref(&projection_ty.trait_ref(f.db), f, true)?;
write!(
f,
">::{} = ",
f.db.type_alias_data(from_assoc_type_id(projection_ty.associated_ty_id)).name,
)?;
ty.hir_fmt(f)?;
}
WhereClause::AliasEq(_) => write!(f, "{{error}}")?,
// FIXME implement these
WhereClause::TypeOutlives(..) => {}
WhereClause::LifetimeOutlives(..) => {}
}
Ok(())
}
}
impl HirDisplay for LifetimeOutlives {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
self.a.hir_fmt(f)?;
write!(f, ": ")?;
self.b.hir_fmt(f)
}
}
impl HirDisplay for Lifetime {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
self.interned().hir_fmt(f)
}
}
impl HirDisplay for LifetimeData {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
match self {
LifetimeData::BoundVar(idx) => idx.hir_fmt(f),
LifetimeData::InferenceVar(_) => write!(f, "_"),
LifetimeData::Placeholder(idx) => {
let id = lt_from_placeholder_idx(f.db, *idx);
let generics = generics(f.db.upcast(), id.parent);
let param_data = &generics.params.lifetimes[id.local_id];
write!(f, "{}", param_data.name)
}
LifetimeData::Static => write!(f, "'static"),
LifetimeData::Empty(_) => Ok(()),
LifetimeData::Erased => Ok(()),
LifetimeData::Phantom(_, _) => Ok(()),
}
}
}
impl HirDisplay for DomainGoal {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
match self {
DomainGoal::Holds(wc) => {
write!(f, "Holds(")?;
wc.hir_fmt(f)?;
write!(f, ")")?;
}
_ => write!(f, "?")?,
}
Ok(())
}
}
pub fn write_visibility(
module_id: ModuleId,
vis: Visibility,
f: &mut HirFormatter,
) -> Result<(), HirDisplayError> {
match vis {
Visibility::Public => write!(f, "pub "),
Visibility::Module(vis_id) => {
let def_map = module_id.def_map(f.db.upcast());
let root_module_id = def_map.module_id(def_map.root());
if vis_id == module_id {
// pub(self) or omitted
Ok(())
} else if root_module_id == vis_id {
write!(f, "pub(crate) ")
} else if module_id.containing_module(f.db.upcast()) == Some(vis_id) {
write!(f, "pub(super) ")
} else {
write!(f, "pub(in ...) ")
}
}
}
}
impl HirDisplay for TypeRef {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
match self {
TypeRef::Never => write!(f, "!")?,
TypeRef::Placeholder => write!(f, "_")?,
TypeRef::Tuple(elems) => {
write!(f, "(")?;
f.write_joined(elems, ", ")?;
if elems.len() == 1 {
write!(f, ",")?;
}
write!(f, ")")?;
}
TypeRef::Path(path) => path.hir_fmt(f)?,
TypeRef::RawPtr(inner, mutability) => {
let mutability = match mutability {
hir_def::type_ref::Mutability::Shared => "*const ",
hir_def::type_ref::Mutability::Mut => "*mut ",
};
write!(f, "{}", mutability)?;
inner.hir_fmt(f)?;
}
TypeRef::Reference(inner, lifetime, mutability) => {
let mutability = match mutability {
hir_def::type_ref::Mutability::Shared => "",
hir_def::type_ref::Mutability::Mut => "mut ",
};
write!(f, "&")?;
if let Some(lifetime) = lifetime {
write!(f, "{} ", lifetime.name)?;
}
write!(f, "{}", mutability)?;
inner.hir_fmt(f)?;
}
TypeRef::Array(inner, len) => {
write!(f, "[")?;
inner.hir_fmt(f)?;
write!(f, "; {}]", len)?;
}
TypeRef::Slice(inner) => {
write!(f, "[")?;
inner.hir_fmt(f)?;
write!(f, "]")?;
}
TypeRef::Fn(tys, is_varargs) => {
// FIXME: Function pointer qualifiers.
write!(f, "fn(")?;
f.write_joined(&tys[..tys.len() - 1], ", ")?;
if *is_varargs {
write!(f, "{}...", if tys.len() == 1 { "" } else { ", " })?;
}
write!(f, ")")?;
let ret_ty = tys.last().unwrap();
match ret_ty {
TypeRef::Tuple(tup) if tup.is_empty() => {}
_ => {
write!(f, " -> ")?;
ret_ty.hir_fmt(f)?;
}
}
}
TypeRef::ImplTrait(bounds) => {
write!(f, "impl ")?;
f.write_joined(bounds, " + ")?;
}
TypeRef::DynTrait(bounds) => {
write!(f, "dyn ")?;
f.write_joined(bounds, " + ")?;
}
TypeRef::Macro(macro_call) => {
let macro_call = macro_call.to_node(f.db.upcast());
let ctx = body::LowerCtx::with_hygiene(f.db.upcast(), &Hygiene::new_unhygienic());
match macro_call.path() {
Some(path) => match Path::from_src(path, &ctx) {
Some(path) => path.hir_fmt(f)?,
None => write!(f, "{{macro}}")?,
},
None => write!(f, "{{macro}}")?,
}
write!(f, "!(..)")?;
}
TypeRef::Error => write!(f, "{{error}}")?,
}
Ok(())
}
}
impl HirDisplay for TypeBound {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
match self {
TypeBound::Path(path, modifier) => {
match modifier {
TraitBoundModifier::None => (),
TraitBoundModifier::Maybe => write!(f, "?")?,
}
path.hir_fmt(f)
}
TypeBound::Lifetime(lifetime) => write!(f, "{}", lifetime.name),
TypeBound::ForLifetime(lifetimes, path) => {
write!(f, "for<{}> ", lifetimes.iter().format(", "))?;
path.hir_fmt(f)
}
TypeBound::Error => write!(f, "{{error}}"),
}
}
}
impl HirDisplay for Path {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
match (self.type_anchor(), self.kind()) {
(Some(anchor), _) => {
write!(f, "<")?;
anchor.hir_fmt(f)?;
write!(f, ">")?;
}
(_, PathKind::Plain) => {}
(_, PathKind::Abs) => {}
(_, PathKind::Crate) => write!(f, "crate")?,
(_, PathKind::Super(0)) => write!(f, "self")?,
(_, PathKind::Super(n)) => {
for i in 0..*n {
if i > 0 {
write!(f, "::")?;
}
write!(f, "super")?;
}
}
(_, PathKind::DollarCrate(_)) => write!(f, "{{extern_crate}}")?,
}
for (seg_idx, segment) in self.segments().iter().enumerate() {
if !matches!(self.kind(), PathKind::Plain) || seg_idx > 0 {
write!(f, "::")?;
}
write!(f, "{}", segment.name)?;
if let Some(generic_args) = segment.args_and_bindings {
// We should be in type context, so format as `Foo<Bar>` instead of `Foo::<Bar>`.
// Do we actually format expressions?
if generic_args.desugared_from_fn {
// First argument will be a tuple, which already includes the parentheses.
// If the tuple only contains 1 item, write it manually to avoid the trailing `,`.
if let hir_def::path::GenericArg::Type(TypeRef::Tuple(v)) =
&generic_args.args[0]
{
if v.len() == 1 {
write!(f, "(")?;
v[0].hir_fmt(f)?;
write!(f, ")")?;
} else {
generic_args.args[0].hir_fmt(f)?;
}
}
if let Some(ret) = &generic_args.bindings[0].type_ref {
if !matches!(ret, TypeRef::Tuple(v) if v.is_empty()) {
write!(f, " -> ")?;
ret.hir_fmt(f)?;
}
}
return Ok(());
}
write!(f, "<")?;
let mut first = true;
for arg in &generic_args.args {
if first {
first = false;
if generic_args.has_self_type {
// FIXME: Convert to `<Ty as Trait>` form.
write!(f, "Self = ")?;
}
} else {
write!(f, ", ")?;
}
arg.hir_fmt(f)?;
}
for binding in &generic_args.bindings {
if first {
first = false;
} else {
write!(f, ", ")?;
}
write!(f, "{}", binding.name)?;
match &binding.type_ref {
Some(ty) => {
write!(f, " = ")?;
ty.hir_fmt(f)?
}
None => {
write!(f, ": ")?;
f.write_joined(&binding.bounds, " + ")?;
}
}
}
write!(f, ">")?;
}
}
Ok(())
}
}
impl HirDisplay for hir_def::path::GenericArg {
fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
match self {
hir_def::path::GenericArg::Type(ty) => ty.hir_fmt(f),
hir_def::path::GenericArg::Lifetime(lifetime) => write!(f, "{}", lifetime.name),
}
}
}