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|
//! Methods for lowering the HIR to types. There are two main cases here:
//!
//! - Lowering a type reference like `&usize` or `Option<foo::bar::Baz>` to a
//! type: The entry point for this is `Ty::from_hir`.
//! - Building the type for an item: This happens through the `type_for_def` query.
//!
//! This usually involves resolving names, collecting generic arguments etc.
use std::sync::Arc;
use crate::{
Function, Struct, StructField, Enum, EnumVariant, Path,
ModuleDef, TypeAlias,
Const, Static,
HirDatabase,
type_ref::TypeRef,
name::KnownName,
nameres::Namespace,
resolve::{Resolver, Resolution},
path::{ PathSegment, GenericArg},
generics::GenericParams,
adt::VariantDef,
};
use super::{Ty, primitive, FnSig, Substs};
impl Ty {
pub(crate) fn from_hir(db: &impl HirDatabase, resolver: &Resolver, type_ref: &TypeRef) -> Self {
match type_ref {
TypeRef::Never => Ty::Never,
TypeRef::Tuple(inner) => {
let inner_tys =
inner.iter().map(|tr| Ty::from_hir(db, resolver, tr)).collect::<Vec<_>>();
Ty::Tuple(Substs(inner_tys.into()))
}
TypeRef::Path(path) => Ty::from_hir_path(db, resolver, path),
TypeRef::RawPtr(inner, mutability) => {
let inner_ty = Ty::from_hir(db, resolver, inner);
Ty::RawPtr(Arc::new(inner_ty), *mutability)
}
TypeRef::Array(inner) => {
let inner_ty = Ty::from_hir(db, resolver, inner);
Ty::Array(Arc::new(inner_ty))
}
TypeRef::Slice(inner) => {
let inner_ty = Ty::from_hir(db, resolver, inner);
Ty::Slice(Arc::new(inner_ty))
}
TypeRef::Reference(inner, mutability) => {
let inner_ty = Ty::from_hir(db, resolver, inner);
Ty::Ref(Arc::new(inner_ty), *mutability)
}
TypeRef::Placeholder => Ty::Unknown,
TypeRef::Fn(params) => {
let inner_tys =
params.iter().map(|tr| Ty::from_hir(db, resolver, tr)).collect::<Vec<_>>();
let sig = Substs(inner_tys.into());
Ty::FnPtr(sig)
}
TypeRef::Error => Ty::Unknown,
}
}
pub(crate) fn from_hir_path(db: &impl HirDatabase, resolver: &Resolver, path: &Path) -> Self {
if let Some(name) = path.as_ident() {
// TODO handle primitive type names in resolver as well?
if let Some(int_ty) = primitive::UncertainIntTy::from_type_name(name) {
return Ty::Int(int_ty);
} else if let Some(float_ty) = primitive::UncertainFloatTy::from_type_name(name) {
return Ty::Float(float_ty);
} else if let Some(known) = name.as_known_name() {
match known {
KnownName::Bool => return Ty::Bool,
KnownName::Char => return Ty::Char,
KnownName::Str => return Ty::Str,
_ => {}
}
}
}
// Resolve the path (in type namespace)
let resolution = resolver.resolve_path(db, path).take_types();
let def = match resolution {
Some(Resolution::Def(def)) => def,
Some(Resolution::LocalBinding(..)) => {
// this should never happen
panic!("path resolved to local binding in type ns");
}
Some(Resolution::GenericParam(idx)) => {
return Ty::Param {
idx,
// TODO: maybe return name in resolution?
name: path
.as_ident()
.expect("generic param should be single-segment path")
.clone(),
};
}
Some(Resolution::SelfType(impl_block)) => {
return impl_block.target_ty(db);
}
None => return Ty::Unknown,
};
let typable: TypableDef = match def.into() {
None => return Ty::Unknown,
Some(it) => it,
};
let ty = db.type_for_def(typable, Namespace::Types);
let substs = Ty::substs_from_path(db, resolver, path, typable);
ty.subst(&substs)
}
pub(super) fn substs_from_path_segment(
db: &impl HirDatabase,
resolver: &Resolver,
segment: &PathSegment,
resolved: TypableDef,
) -> Substs {
let mut substs = Vec::new();
let def_generics = match resolved {
TypableDef::Function(func) => func.generic_params(db),
TypableDef::Struct(s) => s.generic_params(db),
TypableDef::Enum(e) => e.generic_params(db),
TypableDef::EnumVariant(var) => var.parent_enum(db).generic_params(db),
TypableDef::TypeAlias(t) => t.generic_params(db),
TypableDef::Const(_) | TypableDef::Static(_) => GenericParams::default().into(),
};
let parent_param_count = def_generics.count_parent_params();
substs.extend((0..parent_param_count).map(|_| Ty::Unknown));
if let Some(generic_args) = &segment.args_and_bindings {
// if args are provided, it should be all of them, but we can't rely on that
let param_count = def_generics.params.len();
for arg in generic_args.args.iter().take(param_count) {
match arg {
GenericArg::Type(type_ref) => {
let ty = Ty::from_hir(db, resolver, type_ref);
substs.push(ty);
}
}
}
}
// add placeholders for args that were not provided
// TODO: handle defaults
let supplied_params = substs.len();
for _ in supplied_params..def_generics.count_params_including_parent() {
substs.push(Ty::Unknown);
}
assert_eq!(substs.len(), def_generics.count_params_including_parent());
Substs(substs.into())
}
/// Collect generic arguments from a path into a `Substs`. See also
/// `create_substs_for_ast_path` and `def_to_ty` in rustc.
pub(super) fn substs_from_path(
db: &impl HirDatabase,
resolver: &Resolver,
path: &Path,
resolved: TypableDef,
) -> Substs {
let last = path.segments.last().expect("path should have at least one segment");
let segment = match resolved {
TypableDef::Function(_)
| TypableDef::Struct(_)
| TypableDef::Enum(_)
| TypableDef::Const(_)
| TypableDef::Static(_)
| TypableDef::TypeAlias(_) => last,
TypableDef::EnumVariant(_) => {
// the generic args for an enum variant may be either specified
// on the segment referring to the enum, or on the segment
// referring to the variant. So `Option::<T>::None` and
// `Option::None::<T>` are both allowed (though the former is
// preferred). See also `def_ids_for_path_segments` in rustc.
let len = path.segments.len();
let segment = if len >= 2 && path.segments[len - 2].args_and_bindings.is_some() {
// Option::<T>::None
&path.segments[len - 2]
} else {
// Option::None::<T>
last
};
segment
}
};
Ty::substs_from_path_segment(db, resolver, segment, resolved)
}
}
/// Build the declared type of an item. This depends on the namespace; e.g. for
/// `struct Foo(usize)`, we have two types: The type of the struct itself, and
/// the constructor function `(usize) -> Foo` which lives in the values
/// namespace.
pub(crate) fn type_for_def(db: &impl HirDatabase, def: TypableDef, ns: Namespace) -> Ty {
match (def, ns) {
(TypableDef::Function(f), Namespace::Values) => type_for_fn(db, f),
(TypableDef::Struct(s), Namespace::Types) => type_for_struct(db, s),
(TypableDef::Struct(s), Namespace::Values) => type_for_struct_constructor(db, s),
(TypableDef::Enum(e), Namespace::Types) => type_for_enum(db, e),
(TypableDef::EnumVariant(v), Namespace::Values) => type_for_enum_variant_constructor(db, v),
(TypableDef::TypeAlias(t), Namespace::Types) => type_for_type_alias(db, t),
(TypableDef::Const(c), Namespace::Values) => type_for_const(db, c),
(TypableDef::Static(c), Namespace::Values) => type_for_static(db, c),
// 'error' cases:
(TypableDef::Function(_), Namespace::Types) => Ty::Unknown,
(TypableDef::Enum(_), Namespace::Values) => Ty::Unknown,
(TypableDef::EnumVariant(_), Namespace::Types) => Ty::Unknown,
(TypableDef::TypeAlias(_), Namespace::Values) => Ty::Unknown,
(TypableDef::Const(_), Namespace::Types) => Ty::Unknown,
(TypableDef::Static(_), Namespace::Types) => Ty::Unknown,
}
}
/// Build the signature of a callable item (function, struct or enum variant).
pub(crate) fn callable_item_sig(db: &impl HirDatabase, def: CallableDef) -> FnSig {
match def {
CallableDef::Function(f) => fn_sig_for_fn(db, f),
CallableDef::Struct(s) => fn_sig_for_struct_constructor(db, s),
CallableDef::EnumVariant(e) => fn_sig_for_enum_variant_constructor(db, e),
}
}
/// Build the type of a specific field of a struct or enum variant.
pub(crate) fn type_for_field(db: &impl HirDatabase, field: StructField) -> Ty {
let parent_def = field.parent_def(db);
let resolver = match parent_def {
VariantDef::Struct(it) => it.resolver(db),
VariantDef::EnumVariant(it) => it.parent_enum(db).resolver(db),
};
let var_data = parent_def.variant_data(db);
let type_ref = &var_data.fields().unwrap()[field.id].type_ref;
Ty::from_hir(db, &resolver, type_ref)
}
fn fn_sig_for_fn(db: &impl HirDatabase, def: Function) -> FnSig {
let signature = def.signature(db);
let resolver = def.resolver(db);
let params =
signature.params().iter().map(|tr| Ty::from_hir(db, &resolver, tr)).collect::<Vec<_>>();
let ret = Ty::from_hir(db, &resolver, signature.ret_type());
FnSig::from_params_and_return(params, ret)
}
/// Build the declared type of a function. This should not need to look at the
/// function body.
fn type_for_fn(db: &impl HirDatabase, def: Function) -> Ty {
let generics = def.generic_params(db);
let substs = make_substs(&generics);
Ty::FnDef { def: def.into(), substs }
}
/// Build the declared type of a const.
fn type_for_const(db: &impl HirDatabase, def: Const) -> Ty {
let signature = def.signature(db);
let resolver = def.resolver(db);
Ty::from_hir(db, &resolver, signature.type_ref())
}
/// Build the declared type of a static.
fn type_for_static(db: &impl HirDatabase, def: Static) -> Ty {
let signature = def.signature(db);
let resolver = def.resolver(db);
Ty::from_hir(db, &resolver, signature.type_ref())
}
fn fn_sig_for_struct_constructor(db: &impl HirDatabase, def: Struct) -> FnSig {
let var_data = def.variant_data(db);
let fields = match var_data.fields() {
Some(fields) => fields,
None => panic!("fn_sig_for_struct_constructor called on unit struct"),
};
let resolver = def.resolver(db);
let params = fields
.iter()
.map(|(_, field)| Ty::from_hir(db, &resolver, &field.type_ref))
.collect::<Vec<_>>();
let ret = type_for_struct(db, def);
FnSig::from_params_and_return(params, ret)
}
/// Build the type of a tuple struct constructor.
fn type_for_struct_constructor(db: &impl HirDatabase, def: Struct) -> Ty {
let var_data = def.variant_data(db);
if var_data.fields().is_none() {
return type_for_struct(db, def); // Unit struct
}
let generics = def.generic_params(db);
let substs = make_substs(&generics);
Ty::FnDef { def: def.into(), substs }
}
fn fn_sig_for_enum_variant_constructor(db: &impl HirDatabase, def: EnumVariant) -> FnSig {
let var_data = def.variant_data(db);
let fields = match var_data.fields() {
Some(fields) => fields,
None => panic!("fn_sig_for_enum_variant_constructor called for unit variant"),
};
let resolver = def.parent_enum(db).resolver(db);
let params = fields
.iter()
.map(|(_, field)| Ty::from_hir(db, &resolver, &field.type_ref))
.collect::<Vec<_>>();
let generics = def.parent_enum(db).generic_params(db);
let substs = make_substs(&generics);
let ret = type_for_enum(db, def.parent_enum(db)).subst(&substs);
FnSig::from_params_and_return(params, ret)
}
/// Build the type of a tuple enum variant constructor.
fn type_for_enum_variant_constructor(db: &impl HirDatabase, def: EnumVariant) -> Ty {
let var_data = def.variant_data(db);
if var_data.fields().is_none() {
return type_for_enum(db, def.parent_enum(db)); // Unit variant
}
let generics = def.parent_enum(db).generic_params(db);
let substs = make_substs(&generics);
Ty::FnDef { def: def.into(), substs }
}
fn make_substs(generics: &GenericParams) -> Substs {
Substs(
generics
.params_including_parent()
.into_iter()
.map(|p| Ty::Param { idx: p.idx, name: p.name.clone() })
.collect::<Vec<_>>()
.into(),
)
}
fn type_for_struct(db: &impl HirDatabase, s: Struct) -> Ty {
let generics = s.generic_params(db);
Ty::Adt { def_id: s.into(), substs: make_substs(&generics) }
}
fn type_for_enum(db: &impl HirDatabase, s: Enum) -> Ty {
let generics = s.generic_params(db);
Ty::Adt { def_id: s.into(), substs: make_substs(&generics) }
}
fn type_for_type_alias(db: &impl HirDatabase, t: TypeAlias) -> Ty {
let generics = t.generic_params(db);
let resolver = t.resolver(db);
let type_ref = t.type_ref(db);
let substs = make_substs(&generics);
let inner = Ty::from_hir(db, &resolver, &type_ref);
inner.subst(&substs)
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub enum TypableDef {
Function(Function),
Struct(Struct),
Enum(Enum),
EnumVariant(EnumVariant),
TypeAlias(TypeAlias),
Const(Const),
Static(Static),
}
impl_froms!(TypableDef: Function, Struct, Enum, EnumVariant, TypeAlias, Const, Static);
impl From<ModuleDef> for Option<TypableDef> {
fn from(def: ModuleDef) -> Option<TypableDef> {
let res = match def {
ModuleDef::Function(f) => f.into(),
ModuleDef::Struct(s) => s.into(),
ModuleDef::Enum(e) => e.into(),
ModuleDef::EnumVariant(v) => v.into(),
ModuleDef::TypeAlias(t) => t.into(),
ModuleDef::Const(v) => v.into(),
ModuleDef::Static(v) => v.into(),
ModuleDef::Module(_) | ModuleDef::Trait(_) => return None,
};
Some(res)
}
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub enum CallableDef {
Function(Function),
Struct(Struct),
EnumVariant(EnumVariant),
}
impl_froms!(CallableDef: Function, Struct, EnumVariant);
|