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fix(check): Distionguish forall in the top of aliases
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These should be distinct but weren't due to weird quirk of how types
were encoded
```
type Test a = | Test a
type Test = forall a . | Test a
```
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@Marwes
Marwes committed Nov 26, 2018
1 parent 7e472ab commit aee2389
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Showing 15 changed files with 192 additions and 148 deletions.
10 changes: 1 addition & 9 deletions base/src/ast.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@ use ordered_float::NotNan;
use pos::{self, BytePos, HasSpan, Span, Spanned};
use resolve::remove_aliases_cow;
use symbol::Symbol;
use types::{self, Alias, AliasData, ArcType, ArgType, Generic, Type, TypeEnv};
use types::{self, Alias, AliasData, ArcType, ArgType, Type, TypeEnv};

pub trait DisplayEnv {
type Ident;
Expand Down Expand Up @@ -148,14 +148,6 @@ impl<Id> AstType<Id> {
self._typ.typ.value
}

pub fn params_mut(&mut self) -> &mut [Generic<Id>] {
match self._typ.typ.value {
Type::Forall(ref mut params, _, _) => params,
Type::App(ref mut id, _) => id.params_mut(),
_ => &mut [],
}
}

pub fn remove_single_forall(&mut self) -> &mut AstType<Id> {
match self._typ.typ.value {
Type::Forall(_, ref mut typ, _) => typ,
Expand Down
50 changes: 44 additions & 6 deletions base/src/resolve.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ use symbol::Symbol;
use types::{AliasRef, ArcType, Type, TypeEnv};

quick_error! {
#[derive(Debug)]
#[derive(Debug, PartialEq)]
pub enum Error {
UndefinedType(id: Symbol) {
description("undefined type")
Expand Down Expand Up @@ -40,6 +40,40 @@ impl AliasRemover {
self.reduced_aliases.truncate(to)
}

pub fn canonical_alias<'t, F>(
&mut self,
env: &TypeEnv,
typ: &'t ArcType,
mut canonical: F,
) -> Result<Cow<'t, ArcType>, Error>
where
F: FnMut(&AliasRef<Symbol, ArcType>) -> bool,
{
Ok(match peek_alias(env, typ) {
Ok(Some(alias)) => {
if self.reduced_aliases.contains(&alias.name) {
return Err(Error::SelfRecursiveAlias(alias.name.clone()));
}
self.reduced_aliases.push(alias.name.clone());

if canonical(alias) {
Cow::Borrowed(typ)
} else {
match alias
.typ()
.apply_args(alias.params(), &typ.unapplied_args())
{
Some(typ) => {
Cow::Owned(self.canonical_alias(env, &typ, canonical)?.into_owned())
}
None => Cow::Borrowed(typ),
}
}
}
_ => Cow::Borrowed(typ),
})
}

pub fn remove_aliases(&mut self, env: &TypeEnv, mut typ: ArcType) -> Result<ArcType, Error> {
loop {
typ = match self.remove_alias(env, &typ)? {
Expand All @@ -58,10 +92,12 @@ impl AliasRemover {
}
self.reduced_aliases.push(alias.name.clone());
// Opaque types should only exist as the alias itself
if **alias.unresolved_type().remove_forall() == Type::Opaque {
if **alias.unresolved_type() == Type::Opaque {
return Ok(None);
}
Ok(alias.typ().apply_args(&typ.unapplied_args()))
Ok(alias
.typ()
.apply_args(alias.params(), &typ.unapplied_args()))
}
None => Ok(None),
}
Expand Down Expand Up @@ -96,7 +132,7 @@ where
} else {
alias
.typ()
.apply_args(&typ.unapplied_args())
.apply_args(alias.params(), &typ.unapplied_args())
.map(|typ| Cow::Owned(canonical_alias(env, &typ, canonical).into_owned()))
.unwrap_or_else(|| Cow::Borrowed(typ))
}
Expand All @@ -111,10 +147,12 @@ pub fn remove_alias(env: &TypeEnv, typ: &ArcType) -> Result<Option<ArcType>, Err
let typ = typ.skolemize(&mut FnvMap::default());
Ok(peek_alias(env, &typ)?.and_then(|alias| {
// Opaque types should only exist as the alias itself
if **alias.unresolved_type().remove_forall() == Type::Opaque {
if **alias.unresolved_type() == Type::Opaque {
return None;
}
alias.typ().apply_args(&typ.unapplied_args())
alias
.typ()
.apply_args(alias.params(), &typ.unapplied_args())
}))
}

Expand Down
54 changes: 19 additions & 35 deletions base/src/types/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -330,7 +330,7 @@ where
{
fn from(data: AliasData<Id, T>) -> Alias<Id, T> {
Alias {
_typ: Type::alias(data.name, data.typ),
_typ: Type::alias(data.name, data.args, data.typ),
_marker: PhantomData,
}
}
Expand All @@ -346,9 +346,9 @@ impl<Id, T> Alias<Id, T>
where
T: From<Type<Id, T>>,
{
pub fn new(name: Id, typ: T) -> Alias<Id, T> {
pub fn new(name: Id, args: Vec<Generic<Id>>, typ: T) -> Alias<Id, T> {
Alias {
_typ: Type::alias(name, typ),
_typ: Type::alias(name, args, typ),
_marker: PhantomData,
}
}
Expand Down Expand Up @@ -496,6 +496,8 @@ where
pub struct AliasData<Id, T> {
#[cfg_attr(feature = "serde_derive", serde(state))]
pub name: Id,
#[cfg_attr(feature = "serde_derive", serde(state))]
args: Vec<Generic<Id>>,
/// The type that is being aliased
#[cfg_attr(feature = "serde_derive", serde(state))]
typ: T,
Expand All @@ -518,10 +520,7 @@ where
T: From<Type<Id, T>>,
{
pub fn new(name: Id, args: Vec<Generic<Id>>, typ: T) -> AliasData<Id, T> {
AliasData {
name,
typ: Type::forall(args, typ),
}
AliasData { name, args, typ }
}
}

Expand All @@ -530,14 +529,15 @@ where
T: Deref<Target = Type<Id, T>>,
{
pub fn params(&self) -> &[Generic<Id>] {
self.typ.params()
&self.args
}

pub fn params_mut(&mut self) -> &mut [Generic<Id>] {
&mut self.args
}

pub fn aliased_type(&self) -> &T {
match *self.typ {
Type::Forall(_, ref typ, _) => typ,
_ => &self.typ,
}
&self.typ
}
}

Expand Down Expand Up @@ -862,10 +862,10 @@ where
T::from(Type::Variable(typ))
}

pub fn alias(name: Id, typ: T) -> T {
pub fn alias(name: Id, args: Vec<Generic<Id>>, typ: T) -> T {
T::from(Type::Alias(AliasRef {
index: 0,
group: Arc::new(vec![AliasData { name, typ }]),
group: Arc::new(vec![AliasData { name, args, typ }]),
}))
}

Expand Down Expand Up @@ -1363,22 +1363,6 @@ impl<'a, Id> Iterator for ForallScopeIter<'a, Id> {
}

impl ArcType {
pub fn params_mut(&mut self) -> &mut [Generic<Symbol>] {
use std::sync::Arc;

match *Arc::make_mut(&mut self.typ) {
/*
// TODO
Type::Alias(ref mut alias) => {
Arc::make_mut(alias.unresolved_type_mut().typ).params_mut()
}
*/
Type::Forall(ref mut params, _, _) => params,
Type::App(ref mut id, _) => id.params_mut(),
_ => &mut [],
}
}

/// Applies a list of arguments to a parameterised type, returning `Some`
/// if the substitution was successful.
///
Expand All @@ -1389,9 +1373,8 @@ impl ArcType {
/// args = [Error, Option a]
/// result = | Err Error | Ok (Option a)
/// ```
pub fn apply_args(&self, args: &[ArcType]) -> Option<ArcType> {
let params = self.params();
let typ = self.remove_forall().clone();
pub fn apply_args(&self, params: &[Generic<Symbol>], args: &[ArcType]) -> Option<ArcType> {
let typ = self.clone();

// It is ok to take the type only if it is fully applied or if it
// the missing argument only appears in order at the end, i.e:
Expand Down Expand Up @@ -1424,7 +1407,7 @@ impl ArcType {
return None;
};

Some(walk_move_type(typ.remove_forall().clone(), &mut |typ| {
Some(walk_move_type(typ.clone(), &mut |typ| {
match **typ {
Type::Generic(ref generic) => {
// Replace the generic variable with the type from the list
Expand Down Expand Up @@ -2101,7 +2084,7 @@ where
if filter == Filter::RetainKey {
arena.text("...")
} else {
top(remove_forall(&field.typ.typ)).pretty(printer)
top(&field.typ.typ).pretty(printer)
},
if i + 1 != types.len() || print_any_field {
arena.text(",")
Expand Down Expand Up @@ -2551,6 +2534,7 @@ where
{
AliasData {
name: alias.name.clone(),
args: alias.args.clone(),
typ: translate(&alias.typ),
}
}
Expand Down
28 changes: 10 additions & 18 deletions base/tests/types.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -76,10 +76,7 @@ fn show_record_singleton_polymorphic() {
let typ = Type::record(
vec![Field::new(
"Test",
Alias::new(
"Test",
Type::forall(vec![Generic::new("a", Kind::typ())], fun.clone()),
),
Alias::new("Test", vec![Generic::new("a", Kind::typ())], fun.clone()),
)],
vec![],
);
Expand All @@ -93,10 +90,7 @@ fn show_record_multifield() {
let typ = Type::record(
vec![Field::new(
"Test",
Alias::new(
"Test",
Type::forall(vec![Generic::new("a", Kind::typ())], fun.clone()),
),
Alias::new("Test", vec![Generic::new("a", Kind::typ())], fun.clone()),
)],
vec![Field::new("x", Type::int())],
);
Expand Down Expand Up @@ -145,7 +139,10 @@ fn show_record_filtered() {
let data = |s, a| ArcType::from(type_con(s, a));
let test = data("Test", vec![data("a", vec![])]);
let record = Type::record(
vec![Field::new("Test", Alias::new("Test", Type::int()))],
vec![Field::new(
"Test",
Alias::new("Test", Vec::new(), Type::int()),
)],
vec![
Field::new("x", Type::int()),
Field::new("y", Type::int()),
Expand Down Expand Up @@ -198,10 +195,7 @@ fn show_record_multi_line_nested() {
let inner_record = Type::record(
vec![Field::new(
"Test",
Alias::new(
"Test",
Type::forall(vec![Generic::new("a", Kind::typ())], fun.clone()),
),
Alias::new("Test", vec![Generic::new("a", Kind::typ())], fun.clone()),
)],
vec![
Field::new("x", Type::int()),
Expand All @@ -215,10 +209,7 @@ fn show_record_multi_line_nested() {
let record = Type::record(
vec![Field::new(
"Test",
Alias::new(
"Test",
Type::forall(vec![Generic::new("a", Kind::typ())], fun.clone()),
),
Alias::new("Test", vec![Generic::new("a", Kind::typ())], fun.clone()),
)],
vec![
Field::new("x", Type::int()),
Expand Down Expand Up @@ -292,7 +283,8 @@ fn show_polymorphic_record_associated_type() {
"Test",
Alias::new(
"Test",
Type::forall(vec![Generic::new("a", Kind::typ())], Type::ident("a")),
vec![Generic::new("a", Kind::typ())],
Type::ident("a"),
),
)];
let typ: ArcType<&str> = Type::poly_record(type_fields, vec![], Type::ident("r"));
Expand Down
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