use std::rc::Rc;
use rustc_hash::FxHashSet;
use super::checker::{Admissible, TypeChecker};
use super::literal_fit::LiteralFit;
use super::problems::TypeProblems;
use super::ty::{GenericId, Type, TypeVar};
use super::type_text::TypeTextWriter;
use super::typed::{ClosureType, LetValue, TypedDefinition, TypedExpr, TypedExprKind, TypedLeaf};
use super::unifier::LiteralKind;
use crate::core::{BindingId, Literal, PrimitiveType};
use crate::diagnostic::Diagnostic;
use crate::reader::Number;
use crate::source::Span;
#[derive(Clone, Copy)]
enum OpenSite {
WrittenValue(Span),
Elsewhere(Span),
}
impl OpenSite {
fn span(self) -> Span {
match self {
Self::WrittenValue(span) | Self::Elsewhere(span) => span,
}
}
}
#[derive(Clone, Copy)]
enum Enclosure {
Form(Span),
Binder(Span),
AnnotatedBinder(Span),
}
impl Enclosure {
fn of_child(parent_span: Span, let_value: Option<LetValue>) -> Self {
match let_value {
Some(value) if value.annotated => Self::AnnotatedBinder(value.binder_span),
Some(value) => Self::Binder(value.binder_span),
None => Self::Form(parent_span),
}
}
fn site_of(enclosure: Option<Self>, span: Span) -> OpenSite {
match enclosure {
Some(Self::AnnotatedBinder(binder_span)) => OpenSite::Elsewhere(binder_span),
Some(Self::Form(form_span)) if form_span == span => OpenSite::Elsewhere(span),
Some(Self::Binder(binder_span)) if span.contains(binder_span) => {
OpenSite::Elsewhere(span)
}
_ => OpenSite::WrittenValue(span),
}
}
}
pub struct Finalizer<'c> {
checker: &'c mut TypeChecker,
reported: FxHashSet<TypeVar>,
earlier_errors: bool,
closures_in_definition: Vec<Type>,
type_text_operands: Vec<TypedExpr>,
inside_operand: bool,
enclosure: Option<Enclosure>,
}
impl<'c> Finalizer<'c> {
pub fn new(checker: &'c mut TypeChecker) -> Self {
let earlier_errors = checker.diagnostics.has_errors();
Self {
checker,
reported: FxHashSet::default(),
earlier_errors,
closures_in_definition: Vec::new(),
type_text_operands: Vec::new(),
inside_operand: false,
enclosure: None,
}
}
pub fn definition(&mut self, definition: &mut TypedDefinition) {
self.enclosure = Some(Enclosure::Form(definition.span));
self.expr(&mut definition.value);
self.enclosure = None;
self.finalize_type(
&mut definition.scheme.body,
OpenSite::Elsewhere(definition.span),
);
self.record_closure_types(definition.binding);
if self.checker.holds_infer_forms {
self.checker.checking.type_text_walks += 1;
let writer = TypeTextWriter::new(definition.binding, &definition.scheme);
self.write_type_texts(&mut definition.value, &writer);
let operands = std::mem::take(&mut self.type_text_operands);
self.checker
.type_texts
.keep_operands(definition.binding, operands);
}
}
fn write_type_texts(&mut self, expr: &mut TypedExpr, writer: &TypeTextWriter) {
if let TypedExprKind::Infer(operand) = &mut expr.kind {
let text = writer.write(self.checker, operand);
self.finalize_operand(operand, writer);
self.type_text_operands.push(operand.as_ref().clone());
expr.kind = TypedExprKind::Leaf(TypedLeaf::Literal(Literal::String(text)));
return;
}
for child in expr.children_mut() {
self.write_type_texts(child, writer);
}
}
fn finalize_operand(&mut self, operand: &mut TypedExpr, writer: &TypeTextWriter) {
self.inside_operand = true;
self.expr(operand);
self.inside_operand = false;
self.write_type_texts(operand, writer);
self.closures_in_definition.clear();
}
fn record_closure_types(&mut self, definition: BindingId) {
let closures = self
.closures_in_definition
.drain(..)
.map(|ty| ClosureType { definition, ty });
self.checker.closure_types.extend(closures);
}
fn expr(&mut self, expr: &mut TypedExpr) {
let enclosure = self.enclosure;
let site = Enclosure::site_of(enclosure, expr.span);
if let TypedExprKind::Call(callee, arguments) = &mut expr.kind {
if self.checker.unifier.holds_open_literal(&callee.ty) {
self.default_literals(&callee.ty, callee.span);
}
self.enclosure = Some(Enclosure::Form(expr.span));
for argument in arguments {
self.child(&mut argument.value);
}
self.finalize_type(&mut expr.ty, site);
self.child(callee);
} else {
self.children(expr);
self.finalize_type(&mut expr.ty, site);
}
self.enclosure = enclosure;
if let TypedExprKind::Leaf(TypedLeaf::Literal(Literal::Number(number))) = &expr.kind {
self.check_range(number, &expr.ty.clone(), expr.span);
}
self.finalize_wrapped_function(expr);
}
fn children(&mut self, expr: &mut TypedExpr) {
let parent_span = expr.span;
expr.visit_children_mut(&mut |let_value, child| {
self.enclosure = Some(Enclosure::of_child(parent_span, let_value));
self.child(child);
});
for binder in expr.binders_mut() {
self.finalize_type(&mut binder.ty, OpenSite::Elsewhere(binder.span));
}
}
fn child(&mut self, expr: &mut TypedExpr) {
self.expr(expr);
self.note_closure(expr);
}
fn default_literals(&mut self, ty: &Type, span: Span) {
for var in self.checker.free_vars(ty) {
if let Some(kind) = self.checker.unifier.literal_kind(var) {
self.default_literal(var, kind, span);
}
}
}
fn finalize_wrapped_function(&mut self, expr: &mut TypedExpr) {
if let TypedExprKind::Fn(lambda) = &mut expr.kind
&& let Some(wrapped) = &mut Rc::make_mut(lambda).wraps
{
self.finalize_type(&mut wrapped.ty, OpenSite::Elsewhere(expr.span));
}
}
fn note_closure(&mut self, expr: &TypedExpr) {
if let TypedExprKind::Fn(_) = expr.kind {
self.closures_in_definition.push(expr.ty.clone());
}
}
fn finalize_type(&mut self, ty: &mut Type, site: OpenSite) {
for var in self.checker.free_vars(ty) {
self.default_var(var, site, ty);
}
*ty = self.checker.unifier.resolve(ty);
}
fn default_var(&mut self, var: TypeVar, site: OpenSite, ty: &Type) {
match self.checker.unifier.literal_kind(var) {
Some(kind) => self.default_literal(var, kind, site.span()),
None => self.report_unresolved(var, site, ty),
}
}
fn default_literal(&mut self, var: TypeVar, kind: LiteralKind, span: Span) {
let default = match kind {
LiteralKind::Integer => PrimitiveType::I64,
LiteralKind::Float => PrimitiveType::F64,
};
let defaulted =
self.checker
.unifier
.unify(&Type::Var(var), &Type::Primitive(default), span);
debug_assert!(
defaulted.is_ok(),
"a literal variable accepts its default type"
);
}
fn report_unresolved(&mut self, var: TypeVar, site: OpenSite, ty: &Type) {
if !self.inside_operand && self.reported.insert(var) && !self.earlier_errors {
let problem = self.missing_annotation(site, ty);
self.checker.defer_missing_annotation(vec![var], problem);
}
}
fn missing_annotation(&self, site: OpenSite, ty: &Type) -> Diagnostic {
match site {
OpenSite::WrittenValue(span) => {
let open_type = self
.checker
.display()
.show(&self.checker.unifier.resolve(ty));
TypeProblems::cannot_infer_value(&open_type, span)
}
OpenSite::Elsewhere(span) => TypeProblems::cannot_infer(span),
}
}
fn check_range(&mut self, number: &Number, ty: &Type, span: Span) {
match ty {
_ if !LiteralFit::is_representable(number.value()) => {
let widest = PrimitiveType::F64.name();
let diagnostic = TypeProblems::out_of_range(number.text(), widest, span);
self.checker.diagnostics.push(diagnostic);
}
Type::Generic(generic) if !self.checker.literal_generics.contains_key(generic) => {
self.check_generic_literal(number, *generic, span);
}
Type::Primitive(primitive) if !LiteralFit::fits(number.value(), ty) => {
let diagnostic = TypeProblems::out_of_range(number.text(), primitive.name(), span);
self.checker.diagnostics.push(diagnostic);
}
_ => {}
}
}
fn check_generic_literal(&mut self, number: &Number, generic: GenericId, span: Span) {
let display = self.checker.display();
let parameter = display.show(&Type::Generic(generic));
let diagnostic = match self.checker.admissible_types(generic) {
Admissible::Unbounded => Some(TypeProblems::literal_of_any_type(
number.text(),
¶meter,
span,
)),
Admissible::Open(types) | Admissible::Closed(types) => types
.iter()
.find(|candidate| !LiteralFit::fits(number.value(), candidate))
.map(|misfit| {
let names: Vec<String> = types
.iter()
.map(|candidate| display.show(candidate))
.collect();
TypeProblems::literal_misfit(
number.text(),
¶meter,
&display.show(misfit),
&names,
span,
)
}),
};
if let Some(diagnostic) = diagnostic {
self.checker.diagnostics.push(diagnostic);
}
}
}