1249 lines
34 KiB
C++
1249 lines
34 KiB
C++
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// TODO Add list of CST variable names to TVar and unify them so that e.g. the typeclass checker may pick one when displaying a diagnostic
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// TODO make sure that if we have Eq Int, Eq a ~ Eq Int such that an instance binding eq has the correct type
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// TODO make unficiation work like union-find in find()
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#include <algorithm>
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#include <iterator>
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#include <stack>
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#include "llvm/Support/Casting.h"
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#include "zen/config.hpp"
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#include "zen/range.hpp"
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#include "bolt/CSTVisitor.hpp"
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#include "bolt/Diagnostics.hpp"
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#include "bolt/CST.hpp"
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#include "bolt/Checker.hpp"
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namespace bolt {
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std::string describe(const Type* Ty);
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bool TypeclassSignature::operator<(const TypeclassSignature& Other) const {
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if (Id < Other.Id) {
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return true;
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}
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ZEN_ASSERT(Params.size() == 1);
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ZEN_ASSERT(Other.Params.size() == 1);
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return Params[0]->Id < Other.Params[0]->Id;
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}
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bool TypeclassSignature::operator==(const TypeclassSignature& Other) const {
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ZEN_ASSERT(Params.size() == 1);
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ZEN_ASSERT(Other.Params.size() == 1);
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return Id == Other.Id && Params[0]->Id == Other.Params[0]->Id;
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}
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void Type::addTypeVars(TVSet& TVs) {
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switch (Kind) {
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case TypeKind::Var:
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TVs.emplace(static_cast<TVar*>(this));
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break;
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case TypeKind::Arrow:
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{
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auto Arrow = static_cast<TArrow*>(this);
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for (auto Ty: Arrow->ParamTypes) {
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Ty->addTypeVars(TVs);
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}
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Arrow->ReturnType->addTypeVars(TVs);
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break;
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}
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case TypeKind::Con:
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{
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auto Con = static_cast<TCon*>(this);
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for (auto Ty: Con->Args) {
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Ty->addTypeVars(TVs);
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}
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break;
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}
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case TypeKind::Tuple:
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{
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auto Tuple = static_cast<TTuple*>(this);
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for (auto Ty: Tuple->ElementTypes) {
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Ty->addTypeVars(TVs);
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}
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break;
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}
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}
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}
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bool Type::hasTypeVar(const TVar* TV) {
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switch (Kind) {
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case TypeKind::Var:
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return static_cast<TVar*>(this)->Id == TV->Id;
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case TypeKind::Arrow:
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{
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auto Arrow = static_cast<TArrow*>(this);
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for (auto Ty: Arrow->ParamTypes) {
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if (Ty->hasTypeVar(TV)) {
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return true;
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}
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}
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return Arrow->ReturnType->hasTypeVar(TV);
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}
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case TypeKind::Con:
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{
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auto Con = static_cast<TCon*>(this);
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for (auto Ty: Con->Args) {
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if (Ty->hasTypeVar(TV)) {
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return true;
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}
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}
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return false;
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}
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case TypeKind::Tuple:
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{
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auto Tuple = static_cast<TTuple*>(this);
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for (auto Ty: Tuple->ElementTypes) {
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if (Ty->hasTypeVar(TV)) {
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return true;
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}
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}
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return false;
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}
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}
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}
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Type* Type::substitute(const TVSub &Sub) {
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switch (Kind) {
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case TypeKind::Var:
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{
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auto TV = static_cast<TVar*>(this);
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auto Match = Sub.find(TV);
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return Match != Sub.end() ? Match->second->substitute(Sub) : this;
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}
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case TypeKind::Arrow:
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{
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auto Arrow = static_cast<TArrow*>(this);
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bool Changed = false;
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std::vector<Type*> NewParamTypes;
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for (auto Ty: Arrow->ParamTypes) {
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auto NewParamType = Ty->substitute(Sub);
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if (NewParamType != Ty) {
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Changed = true;
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}
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NewParamTypes.push_back(NewParamType);
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}
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auto NewRetTy = Arrow->ReturnType->substitute(Sub) ;
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if (NewRetTy != Arrow->ReturnType) {
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Changed = true;
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}
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return Changed ? new TArrow(NewParamTypes, NewRetTy) : this;
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}
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case TypeKind::Con:
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{
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auto Con = static_cast<TCon*>(this);
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bool Changed = false;
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std::vector<Type*> NewArgs;
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for (auto Arg: Con->Args) {
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auto NewArg = Arg->substitute(Sub);
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if (NewArg != Arg) {
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Changed = true;
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}
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NewArgs.push_back(NewArg);
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}
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return Changed ? new TCon(Con->Id, NewArgs, Con->DisplayName) : this;
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}
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case TypeKind::Tuple:
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{
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auto Tuple = static_cast<TTuple*>(this);
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bool Changed = false;
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std::vector<Type*> NewElementTypes;
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for (auto Ty: Tuple->ElementTypes) {
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auto NewElementType = Ty->substitute(Sub);
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if (NewElementType != Ty) {
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Changed = true;
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}
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NewElementTypes.push_back(NewElementType);
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}
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return Changed ? new TTuple(NewElementTypes) : this;
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}
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}
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}
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Constraint* Constraint::substitute(const TVSub &Sub) {
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switch (Kind) {
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case ConstraintKind::Class:
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{
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auto Class = static_cast<CClass*>(this);
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std::vector<Type*> NewTypes;
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for (auto Ty: Class->Types) {
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NewTypes.push_back(Ty->substitute(Sub));
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}
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return new CClass(Class->Name, NewTypes);
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}
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case ConstraintKind::Equal:
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{
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auto Equal = static_cast<CEqual*>(this);
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return new CEqual(Equal->Left->substitute(Sub), Equal->Right->substitute(Sub), Equal->Source);
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}
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case ConstraintKind::Many:
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{
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auto Many = static_cast<CMany*>(this);
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auto NewConstraints = new ConstraintSet();
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for (auto Element: Many->Elements) {
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NewConstraints->push_back(Element->substitute(Sub));
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}
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return new CMany(*NewConstraints);
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}
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case ConstraintKind::Empty:
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return this;
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}
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}
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Checker::Checker(const LanguageConfig& Config, DiagnosticEngine& DE):
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Config(Config), DE(DE) {
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BoolType = new TCon(NextConTypeId++, {}, "Bool");
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IntType = new TCon(NextConTypeId++, {}, "Int");
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StringType = new TCon(NextConTypeId++, {}, "String");
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}
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Scheme* Checker::lookup(ByteString Name) {
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for (auto Iter = Contexts.rbegin(); Iter != Contexts.rend(); Iter++) {
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auto Curr = *Iter;
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auto Match = Curr->Env.find(Name);
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if (Match != Curr->Env.end()) {
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return Match->second;
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}
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}
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return nullptr;
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}
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Type* Checker::lookupMono(ByteString Name) {
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auto Scm = lookup(Name);
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if (Scm == nullptr) {
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return nullptr;
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}
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auto F = static_cast<Forall*>(Scm);
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ZEN_ASSERT(F->TVs == nullptr || F->TVs->empty());
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return F->Type;
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}
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void Checker::addBinding(ByteString Name, Scheme* Scm) {
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for (auto Iter = Contexts.rbegin(); Iter != Contexts.rend(); Iter++) {
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auto& Ctx = **Iter;
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if (!Ctx.isEnvPervious()) {
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Ctx.Env.emplace(Name, Scm);
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return;
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}
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}
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ZEN_UNREACHABLE
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}
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Type* Checker::getReturnType() {
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auto Ty = Contexts.back()->ReturnType;
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ZEN_ASSERT(Ty != nullptr);
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return Ty;
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}
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static bool hasTypeVar(TVSet& Set, Type* Type) {
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for (auto TV: Type->getTypeVars()) {
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if (Set.count(TV)) {
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return true;
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}
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}
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return false;
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}
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InferContext& Checker::getContext() {
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ZEN_ASSERT(!Contexts.empty());
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return *Contexts.back();
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}
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void Checker::addConstraint(Constraint* C) {
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switch (C->getKind()) {
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case ConstraintKind::Class:
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{
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Contexts.back()->Constraints->push_back(C);
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break;
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}
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case ConstraintKind::Equal:
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{
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auto Y = static_cast<CEqual*>(C);
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std::size_t MaxLevel = 0;
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for (std::size_t I = Contexts.size(); I-- > 0; ) {
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auto Ctx = Contexts[I];
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if (hasTypeVar(*Ctx->TVs, Y->Left) || hasTypeVar(*Ctx->TVs, Y->Right)) {
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MaxLevel = I;
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break;
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}
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}
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std::size_t MinLevel = MaxLevel;
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for (std::size_t I = 0; I < Contexts.size(); I++) {
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auto Ctx = Contexts[I];
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if (hasTypeVar(*Ctx->TVs, Y->Left) || hasTypeVar(*Ctx->TVs, Y->Right)) {
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MinLevel = I;
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break;
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}
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}
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if (MaxLevel == MinLevel) {
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solveCEqual(Y);
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} else {
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Contexts[MaxLevel]->Constraints->push_back(C);
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}
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// Contexts.front()->Constraints->push_back(C);
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//auto I = std::max(Y->Left->MaxDepth, Y->Right->MaxDepth);
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//ZEN_ASSERT(I < Contexts.size());
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//auto Ctx = Contexts[I];
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//Ctx->Constraints.push_back(Constraint);
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break;
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}
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case ConstraintKind::Many:
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{
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auto Y = static_cast<CMany*>(C);
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for (auto Element: Y->Elements) {
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addConstraint(Element);
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}
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break;
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}
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case ConstraintKind::Empty:
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break;
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}
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}
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void Checker::addClass(TypeclassSignature Sig) {
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getContext().Classes.push_back(Sig);
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}
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void Checker::forwardDeclare(Node* X) {
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switch (X->getKind()) {
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case NodeKind::ExpressionStatement:
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case NodeKind::ReturnStatement:
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case NodeKind::IfStatement:
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break;
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case NodeKind::SourceFile:
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{
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auto File = static_cast<SourceFile*>(X);
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for (auto Element: File->Elements) {
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forwardDeclare(Element) ;
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}
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break;
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}
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case NodeKind::ClassDeclaration:
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{
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auto Class = static_cast<ClassDeclaration*>(X);
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for (auto TE: Class->TypeVars) {
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auto TV = createRigidVar(TE->Name->getCanonicalText());
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TV->Contexts.emplace(Class->Name->getCanonicalText());
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TE->setType(TV);
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}
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for (auto Element: Class->Elements) {
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forwardDeclare(Element);
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}
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break;
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}
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case NodeKind::InstanceDeclaration:
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{
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auto Decl = static_cast<InstanceDeclaration*>(X);
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auto Match = InstanceMap.find(Decl->Name->getCanonicalText());
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if (Match == InstanceMap.end()) {
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InstanceMap.emplace(Decl->Name->getCanonicalText(), std::vector { Decl });
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} else {
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Match->second.push_back(Decl);
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}
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auto Ctx = createInferContext();
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Contexts.push_back(Ctx);
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for (auto Element: Decl->Elements) {
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forwardDeclare(Element);
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}
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Contexts.pop_back();
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break;
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}
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case NodeKind::LetDeclaration:
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{
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auto Let = static_cast<LetDeclaration*>(X);
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auto NewCtx = createInferContext();
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Let->Ctx = NewCtx;
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Contexts.push_back(NewCtx);
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// If declaring a let-declaration inside a type class declaration,
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// we need to mark that the let-declaration requires this class.
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// This marking is set on the rigid type variables of the class, which
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// are then added to this local type environment.
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if (llvm::isa<ClassDeclaration>(Let->Parent)) {
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auto Decl = static_cast<ClassDeclaration*>(Let->Parent);
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for (auto TE: Decl->TypeVars) {
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auto TV = llvm::cast<TVar>(TE->getType());
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NewCtx->Env.emplace(TE->Name->getCanonicalText(), new Forall(TV));
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NewCtx->TVs->emplace(TV);
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}
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}
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Type* Ty;
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if (Let->TypeAssert) {
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Ty = inferTypeExpression(Let->TypeAssert->TypeExpression);
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} else {
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Ty = createTypeVar();
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}
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Let->Ty = Ty;
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if (Let->Body) {
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switch (Let->Body->getKind()) {
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case NodeKind::LetExprBody:
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break;
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case NodeKind::LetBlockBody:
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{
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auto Block = static_cast<LetBlockBody*>(Let->Body);
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NewCtx->ReturnType = createTypeVar();
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for (auto Element: Block->Elements) {
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forwardDeclare(Element);
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}
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break;
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}
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default:
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ZEN_UNREACHABLE
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}
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}
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Contexts.pop_back();
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inferBindings(Let->Pattern, Ty, NewCtx->Constraints, NewCtx->TVs);
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break;
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}
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default:
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ZEN_UNREACHABLE
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}
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}
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void Checker::infer(Node* N) {
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switch (N->getKind()) {
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case NodeKind::SourceFile:
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{
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auto File = static_cast<SourceFile*>(N);
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for (auto Element: File->Elements) {
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infer(Element);
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}
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break;
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}
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case NodeKind::ClassDeclaration:
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{
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auto Decl = static_cast<ClassDeclaration*>(N);
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for (auto Element: Decl->Elements) {
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infer(Element);
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}
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break;
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}
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case NodeKind::InstanceDeclaration:
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{
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auto Decl = static_cast<InstanceDeclaration*>(N);
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// Needed to set the associated Type on the CST node
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for (auto TE: Decl->TypeExps) {
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inferTypeExpression(TE);
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}
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for (auto Element: Decl->Elements) {
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infer(Element);
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}
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break;
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}
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case NodeKind::IfStatement:
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{
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auto IfStmt = static_cast<IfStatement*>(N);
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for (auto Part: IfStmt->Parts) {
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if (Part->Test != nullptr) {
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addConstraint(new CEqual { BoolType, inferExpression(Part->Test), Part->Test });
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}
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for (auto Element: Part->Elements) {
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infer(Element);
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}
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}
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break;
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}
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case NodeKind::LetDeclaration:
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{
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auto Decl = static_cast<LetDeclaration*>(N);
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auto NewCtx = Decl->Ctx;
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Contexts.push_back(NewCtx);
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std::vector<Type*> ParamTypes;
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Type* RetType;
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for (auto Param: Decl->Params) {
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// TODO incorporate Param->TypeAssert or make it a kind of pattern
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TVar* TV = createTypeVar();
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inferBindings(Param->Pattern, TV);
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ParamTypes.push_back(TV);
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}
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if (Decl->Body) {
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switch (Decl->Body->getKind()) {
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case NodeKind::LetExprBody:
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{
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auto Expr = static_cast<LetExprBody*>(Decl->Body);
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RetType = inferExpression(Expr->Expression);
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break;
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}
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case NodeKind::LetBlockBody:
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{
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auto Block = static_cast<LetBlockBody*>(Decl->Body);
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RetType = createTypeVar();
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for (auto Element: Block->Elements) {
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infer(Element);
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}
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break;
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}
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default:
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ZEN_UNREACHABLE
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}
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} else {
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RetType = createTypeVar();
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}
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if (ParamTypes.empty()) {
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// Declaration is a plain (typed) variable
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addConstraint(new CEqual { Decl->Ty, RetType, N });
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} else {
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// Declaration is a function
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addConstraint(new CEqual { Decl->Ty, new TArrow(ParamTypes, RetType), N });
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}
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Contexts.pop_back();
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break;
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}
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|
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case NodeKind::ReturnStatement:
|
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{
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|
auto RetStmt = static_cast<ReturnStatement*>(N);
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Type* ReturnType;
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if (RetStmt->Expression) {
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ReturnType = inferExpression(RetStmt->Expression);
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} else {
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ReturnType = new TTuple({});
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}
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addConstraint(new CEqual { ReturnType, getReturnType(), N });
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break;
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}
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|
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case NodeKind::ExpressionStatement:
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{
|
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auto ExprStmt = static_cast<ExpressionStatement*>(N);
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inferExpression(ExprStmt->Expression);
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break;
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}
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default:
|
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ZEN_UNREACHABLE
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|
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}
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|
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}
|
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|
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TVarRigid* Checker::createRigidVar(ByteString Name) {
|
|
auto TV = new TVarRigid(NextTypeVarId++, Name);
|
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Contexts.back()->TVs->emplace(TV);
|
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return TV;
|
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}
|
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|
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TVar* Checker::createTypeVar() {
|
|
auto TV = new TVar(NextTypeVarId++, VarKind::Unification);
|
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Contexts.back()->TVs->emplace(TV);
|
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return TV;
|
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}
|
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|
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InferContext* Checker::createInferContext() {
|
|
auto Ctx = new InferContext;
|
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Ctx->TVs = new TVSet;
|
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Ctx->Constraints = new ConstraintSet;
|
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return Ctx;
|
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}
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|
|
Type* Checker::instantiate(Scheme* Scm, Node* Source) {
|
|
|
|
switch (Scm->getKind()) {
|
|
|
|
case SchemeKind::Forall:
|
|
{
|
|
auto F = static_cast<Forall*>(Scm);
|
|
|
|
TVSub Sub;
|
|
for (auto TV: *F->TVs) {
|
|
auto Fresh = createTypeVar();
|
|
Fresh->Contexts = TV->Contexts;
|
|
Sub[TV] = Fresh;
|
|
}
|
|
|
|
for (auto Constraint: *F->Constraints) {
|
|
|
|
auto NewConstraint = Constraint->substitute(Sub);
|
|
|
|
// This makes error messages prettier by relating the typing failure
|
|
// to the call site rather than the definition.
|
|
if (NewConstraint->getKind() == ConstraintKind::Equal) {
|
|
static_cast<CEqual *>(NewConstraint)->Source = Source;
|
|
}
|
|
|
|
addConstraint(NewConstraint);
|
|
}
|
|
|
|
return F->Type->substitute(Sub);
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
Constraint* Checker::convertToConstraint(ConstraintExpression* C) {
|
|
switch (C->getKind()) {
|
|
case NodeKind::TypeclassConstraintExpression:
|
|
{
|
|
auto D = static_cast<TypeclassConstraintExpression*>(C);
|
|
std::vector<Type*> Types;
|
|
for (auto TE: D->TEs) {
|
|
Types.push_back(inferTypeExpression(TE));
|
|
}
|
|
return new CClass(D->Name->getCanonicalText(), Types);
|
|
}
|
|
case NodeKind::EqualityConstraintExpression:
|
|
{
|
|
auto D = static_cast<EqualityConstraintExpression*>(C);
|
|
return new CEqual(inferTypeExpression(D->Left), inferTypeExpression(D->Right), C);
|
|
}
|
|
default:
|
|
ZEN_UNREACHABLE
|
|
}
|
|
}
|
|
|
|
Type* Checker::inferTypeExpression(TypeExpression* N) {
|
|
|
|
switch (N->getKind()) {
|
|
|
|
case NodeKind::ReferenceTypeExpression:
|
|
{
|
|
auto RefTE = static_cast<ReferenceTypeExpression*>(N);
|
|
auto Ty = lookupMono(RefTE->Name->getCanonicalText());
|
|
if (Ty == nullptr) {
|
|
if (Config.typeVarsRequireForall()) {
|
|
DE.add<BindingNotFoundDiagnostic>(RefTE->Name->getCanonicalText(), RefTE->Name);
|
|
}
|
|
Ty = createTypeVar();
|
|
}
|
|
N->setType(Ty);
|
|
return Ty;
|
|
}
|
|
|
|
case NodeKind::VarTypeExpression:
|
|
{
|
|
auto VarTE = static_cast<VarTypeExpression*>(N);
|
|
auto Ty = lookupMono(VarTE->Name->getCanonicalText());
|
|
if (Ty == nullptr) {
|
|
if (Config.typeVarsRequireForall()) {
|
|
DE.add<BindingNotFoundDiagnostic>(VarTE->Name->getCanonicalText(), VarTE->Name);
|
|
}
|
|
Ty = createRigidVar(VarTE->Name->getCanonicalText());
|
|
addBinding(VarTE->Name->getCanonicalText(), new Forall(Ty));
|
|
}
|
|
N->setType(Ty);
|
|
return Ty;
|
|
}
|
|
|
|
case NodeKind::ArrowTypeExpression:
|
|
{
|
|
auto ArrowTE = static_cast<ArrowTypeExpression*>(N);
|
|
std::vector<Type*> ParamTypes;
|
|
for (auto ParamType: ArrowTE->ParamTypes) {
|
|
ParamTypes.push_back(inferTypeExpression(ParamType));
|
|
}
|
|
auto ReturnType = inferTypeExpression(ArrowTE->ReturnType);
|
|
auto Ty = new TArrow(ParamTypes, ReturnType);
|
|
N->setType(Ty);
|
|
return Ty;
|
|
}
|
|
|
|
case NodeKind::QualifiedTypeExpression:
|
|
{
|
|
auto QTE = static_cast<QualifiedTypeExpression*>(N);
|
|
for (auto [C, Comma]: QTE->Constraints) {
|
|
addConstraint(convertToConstraint(C));
|
|
}
|
|
auto Ty = inferTypeExpression(QTE->TE);
|
|
N->setType(Ty);
|
|
return Ty;
|
|
}
|
|
|
|
default:
|
|
ZEN_UNREACHABLE
|
|
|
|
}
|
|
}
|
|
|
|
Type* Checker::inferExpression(Expression* X) {
|
|
|
|
switch (X->getKind()) {
|
|
|
|
case NodeKind::MatchExpression:
|
|
{
|
|
auto Match = static_cast<MatchExpression*>(X);
|
|
Type* ValTy;
|
|
if (Match->Value) {
|
|
ValTy = inferExpression(Match->Value);
|
|
} else {
|
|
ValTy = createTypeVar();
|
|
}
|
|
auto ResTy = createTypeVar();
|
|
for (auto Case: Match->Cases) {
|
|
auto NewCtx = createInferContext();
|
|
Contexts.push_back(NewCtx);
|
|
inferBindings(Case->Pattern, ValTy);
|
|
auto Ty = inferExpression(Case->Expression);
|
|
addConstraint(new CEqual(Ty, ResTy, Case->Expression));
|
|
Contexts.pop_back();
|
|
}
|
|
if (!Match->Value) {
|
|
return new TArrow({ ValTy }, ResTy);
|
|
}
|
|
return ResTy;
|
|
}
|
|
|
|
case NodeKind::ConstantExpression:
|
|
{
|
|
auto Const = static_cast<ConstantExpression*>(X);
|
|
Type* Ty = nullptr;
|
|
switch (Const->Token->getKind()) {
|
|
case NodeKind::IntegerLiteral:
|
|
Ty = lookupMono("Int");
|
|
break;
|
|
case NodeKind::StringLiteral:
|
|
Ty = lookupMono("String");
|
|
break;
|
|
default:
|
|
ZEN_UNREACHABLE
|
|
}
|
|
ZEN_ASSERT(Ty != nullptr);
|
|
X->setType(Ty);
|
|
return Ty;
|
|
}
|
|
|
|
case NodeKind::ReferenceExpression:
|
|
{
|
|
auto Ref = static_cast<ReferenceExpression*>(X);
|
|
ZEN_ASSERT(Ref->ModulePath.empty());
|
|
auto Ctx = lookupCall(Ref, Ref->getSymbolPath());
|
|
if (Ctx) {
|
|
/* std::cerr << "recursive call!\n"; */
|
|
ZEN_ASSERT(Ctx->ReturnType != nullptr);
|
|
return Ctx->ReturnType;
|
|
}
|
|
auto Scm = lookup(Ref->Name->getCanonicalText());
|
|
if (Scm == nullptr) {
|
|
DE.add<BindingNotFoundDiagnostic>(Ref->Name->getCanonicalText(), Ref->Name);
|
|
return createTypeVar();
|
|
}
|
|
auto Ty = instantiate(Scm, X);
|
|
X->setType(Ty);
|
|
return Ty;
|
|
}
|
|
|
|
case NodeKind::CallExpression:
|
|
{
|
|
auto Call = static_cast<CallExpression*>(X);
|
|
auto OpTy = inferExpression(Call->Function);
|
|
auto RetType = createTypeVar();
|
|
std::vector<Type*> ArgTypes;
|
|
for (auto Arg: Call->Args) {
|
|
ArgTypes.push_back(inferExpression(Arg));
|
|
}
|
|
addConstraint(new CEqual { OpTy, new TArrow(ArgTypes, RetType), X });
|
|
X->setType(RetType);
|
|
return RetType;
|
|
}
|
|
|
|
case NodeKind::InfixExpression:
|
|
{
|
|
auto Infix = static_cast<InfixExpression*>(X);
|
|
auto Scm = lookup(Infix->Operator->getText());
|
|
if (Scm == nullptr) {
|
|
DE.add<BindingNotFoundDiagnostic>(Infix->Operator->getText(), Infix->Operator);
|
|
return createTypeVar();
|
|
}
|
|
auto OpTy = instantiate(Scm, Infix->Operator);
|
|
auto RetTy = createTypeVar();
|
|
std::vector<Type*> ArgTys;
|
|
ArgTys.push_back(inferExpression(Infix->LHS));
|
|
ArgTys.push_back(inferExpression(Infix->RHS));
|
|
addConstraint(new CEqual { new TArrow(ArgTys, RetTy), OpTy, X });
|
|
X->setType(RetTy);
|
|
return RetTy;
|
|
}
|
|
|
|
case NodeKind::NestedExpression:
|
|
{
|
|
auto Nested = static_cast<NestedExpression*>(X);
|
|
return inferExpression(Nested->Inner);
|
|
}
|
|
|
|
default:
|
|
ZEN_UNREACHABLE
|
|
|
|
}
|
|
|
|
}
|
|
|
|
void Checker::inferBindings(
|
|
Pattern* Pattern,
|
|
Type* Type,
|
|
ConstraintSet* Constraints,
|
|
TVSet* TVs
|
|
) {
|
|
|
|
switch (Pattern->getKind()) {
|
|
|
|
case NodeKind::BindPattern:
|
|
{
|
|
addBinding(static_cast<BindPattern*>(Pattern)->Name->getCanonicalText(), new Forall(TVs, Constraints, Type));
|
|
break;
|
|
}
|
|
|
|
default:
|
|
ZEN_UNREACHABLE
|
|
|
|
}
|
|
|
|
}
|
|
|
|
void Checker::inferBindings(Pattern* Pattern, Type* Type) {
|
|
inferBindings(Pattern, Type, new ConstraintSet, new TVSet);
|
|
}
|
|
|
|
void collectTypeclasses(LetDeclaration* Decl, std::vector<TypeclassSignature>& Out) {
|
|
if (llvm::isa<ClassDeclaration>(Decl->Parent)) {
|
|
auto Class = llvm::cast<ClassDeclaration>(Decl->Parent);
|
|
std::vector<TVar*> Tys;
|
|
for (auto TE: Class->TypeVars) {
|
|
Tys.push_back(llvm::cast<TVar>(TE->getType()));
|
|
}
|
|
Out.push_back(TypeclassSignature { Class->Name->getCanonicalText(), Tys });
|
|
}
|
|
if (Decl->TypeAssert != nullptr) {
|
|
if (llvm::isa<QualifiedTypeExpression>(Decl->TypeAssert->TypeExpression)) {
|
|
auto QTE = static_cast<QualifiedTypeExpression*>(Decl->TypeAssert->TypeExpression);
|
|
for (auto [C, Comma]: QTE->Constraints) {
|
|
if (llvm::isa<TypeclassConstraintExpression>(C)) {
|
|
auto TCE = static_cast<TypeclassConstraintExpression*>(C);
|
|
std::vector<TVar*> Tys;
|
|
for (auto TE: TCE->TEs) {
|
|
auto TV = TE->getType();
|
|
ZEN_ASSERT(llvm::isa<TVar>(TV));
|
|
Tys.push_back(static_cast<TVar*>(TV));
|
|
}
|
|
Out.push_back(TypeclassSignature { TCE->Name->getCanonicalText(), Tys });
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void Checker::checkTypeclassSigs(Node* N) {
|
|
|
|
struct LetVisitor : CSTVisitor<LetVisitor> {
|
|
|
|
Checker& C;
|
|
|
|
void visitLetDeclaration(LetDeclaration* Decl) {
|
|
|
|
std::vector<TypeclassSignature> Expected;
|
|
collectTypeclasses(Decl, Expected);
|
|
std::sort(Expected.begin(), Expected.end());
|
|
Expected.erase(std::unique(Expected.begin(), Expected.end()), Expected.end());
|
|
|
|
std::vector<TypeclassSignature> Actual;
|
|
for (auto Ty: *Decl->Ctx->TVs) {
|
|
auto S = Ty->substitute(C.Solution);
|
|
if (llvm::isa<TVar>(S)) {
|
|
auto TV = static_cast<TVar*>(S);
|
|
for (auto Class: TV->Contexts) {
|
|
Actual.push_back(TypeclassSignature { Class, { TV } });
|
|
}
|
|
}
|
|
}
|
|
std::sort(Actual.begin(), Actual.end());
|
|
Actual.erase(std::unique(Actual.begin(), Actual.end()), Actual.end());
|
|
|
|
auto It1 = Actual.begin();
|
|
auto It2 = Expected.begin();
|
|
|
|
for (; It1 != Actual.end() || It2 != Expected.end() ;) {
|
|
if (It1 == Actual.end()) {
|
|
// TODO Maybe issue a warning that a type class went unused
|
|
break;
|
|
}
|
|
if (It2 == Expected.end()) {
|
|
for (; It1 != Actual.end(); It1++) {
|
|
C.DE.add<TypeclassMissingDiagnostic>(*It1, Decl);
|
|
}
|
|
break;
|
|
}
|
|
if (*It1 < *It2) {
|
|
// FIXME It1->Ty needs to be unified with potential candidate It2->Ty
|
|
C.DE.add<TypeclassMissingDiagnostic>(*It1, Decl);
|
|
It1++;
|
|
continue;
|
|
}
|
|
if (*It2 < *It1) {
|
|
// DE.add<TypeclassMissingDiagnostic>(It2->Name, Decl);
|
|
It2++;
|
|
continue;
|
|
}
|
|
It1++;
|
|
It2++;
|
|
}
|
|
|
|
}
|
|
|
|
};
|
|
|
|
LetVisitor V { {}, *this };
|
|
V.visit(N);
|
|
|
|
}
|
|
|
|
void Checker::check(SourceFile *SF) {
|
|
auto RootContext = createInferContext();
|
|
Contexts.push_back(RootContext);
|
|
addBinding("String", new Forall(StringType));
|
|
addBinding("Int", new Forall(IntType));
|
|
addBinding("Bool", new Forall(BoolType));
|
|
addBinding("True", new Forall(BoolType));
|
|
addBinding("False", new Forall(BoolType));
|
|
auto A = createTypeVar();
|
|
addBinding("==", new Forall(new TVSet { A }, new ConstraintSet, new TArrow({ A, A }, BoolType)));
|
|
addBinding("+", new Forall(new TArrow({ IntType, IntType }, IntType)));
|
|
addBinding("-", new Forall(new TArrow({ IntType, IntType }, IntType)));
|
|
addBinding("*", new Forall(new TArrow({ IntType, IntType }, IntType)));
|
|
addBinding("/", new Forall(new TArrow({ IntType, IntType }, IntType)));
|
|
forwardDeclare(SF);
|
|
infer(SF);
|
|
Contexts.pop_back();
|
|
solve(new CMany(*RootContext->Constraints), Solution);
|
|
checkTypeclassSigs(SF);
|
|
}
|
|
|
|
void Checker::solve(Constraint* Constraint, TVSub& Solution) {
|
|
|
|
std::stack<class Constraint*> Queue;
|
|
Queue.push(Constraint);
|
|
|
|
while (!Queue.empty()) {
|
|
|
|
auto Constraint = Queue.top();
|
|
|
|
Queue.pop();
|
|
|
|
switch (Constraint->getKind()) {
|
|
|
|
case ConstraintKind::Class:
|
|
{
|
|
// TODO
|
|
break;
|
|
}
|
|
|
|
case ConstraintKind::Empty:
|
|
break;
|
|
|
|
case ConstraintKind::Many:
|
|
{
|
|
auto Many = static_cast<CMany*>(Constraint);
|
|
for (auto Constraint: Many->Elements) {
|
|
Queue.push(Constraint);
|
|
}
|
|
break;
|
|
}
|
|
|
|
case ConstraintKind::Equal:
|
|
{
|
|
solveCEqual(static_cast<CEqual*>(Constraint));
|
|
break;
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
bool assignableTo(Type* A, Type* B) {
|
|
if (llvm::isa<TCon>(A) && llvm::isa<TCon>(B)) {
|
|
auto Con1 = llvm::cast<TCon>(A);
|
|
auto Con2 = llvm::cast<TCon>(B);
|
|
if (Con1->Id != Con2-> Id) {
|
|
return false;
|
|
}
|
|
ZEN_ASSERT(Con1->Args.size() == Con2->Args.size());
|
|
for (auto [T1, T2]: zen::zip(Con1->Args, Con2->Args)) {
|
|
if (!assignableTo(T1, T2)) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
ZEN_UNREACHABLE
|
|
}
|
|
|
|
std::vector<TypeclassContext> Checker::findInstanceContext(TCon* Ty, TypeclassId& Class, Node* Source) {
|
|
auto Match = InstanceMap.find(Class);
|
|
std::vector<TypeclassContext> S;
|
|
if (Match != InstanceMap.end()) {
|
|
for (auto Instance: Match->second) {
|
|
if (assignableTo(Ty, Instance->TypeExps[0]->getType())) {
|
|
std::vector<TypeclassContext> S;
|
|
for (auto Arg: Ty->Args) {
|
|
TypeclassContext Classes;
|
|
// TODO
|
|
S.push_back(Classes);
|
|
}
|
|
return S;
|
|
}
|
|
}
|
|
}
|
|
DE.add<InstanceNotFoundDiagnostic>(Class, Ty, Source);
|
|
for (auto Arg: Ty->Args) {
|
|
S.push_back({});
|
|
}
|
|
return S;
|
|
}
|
|
|
|
void Checker::propagateClasses(std::unordered_set<TypeclassId>& Classes, Type* Ty, Node* Source) {
|
|
if (llvm::isa<TVar>(Ty)) {
|
|
auto TV = llvm::cast<TVar>(Ty);
|
|
for (auto Class: Classes) {
|
|
TV->Contexts.emplace(Class);
|
|
}
|
|
} else if (llvm::isa<TCon>(Ty)) {
|
|
for (auto Class: Classes) {
|
|
propagateClassTycon(Class, llvm::cast<TCon>(Ty), Source);
|
|
}
|
|
} else {
|
|
ZEN_UNREACHABLE
|
|
// DE.add<InvalidArgumentToTypeclassDiagnostic>(Ty);
|
|
}
|
|
};
|
|
|
|
void Checker::propagateClassTycon(TypeclassId& Class, TCon* Ty, Node* Source) {
|
|
auto S = findInstanceContext(Ty, Class, Source);
|
|
for (auto [Classes, Arg]: zen::zip(S, Ty->Args)) {
|
|
propagateClasses(Classes, Arg, Source);
|
|
}
|
|
};
|
|
|
|
class ArrowCursor {
|
|
|
|
std::stack<std::tuple<TArrow*, std::size_t>> Path;
|
|
|
|
public:
|
|
|
|
ArrowCursor(TArrow* Arr) {
|
|
Path.push({ Arr, 0 });
|
|
}
|
|
|
|
Type* next() {
|
|
while (!Path.empty()) {
|
|
auto& [Arr, I] = Path.top();
|
|
Type* Ty;
|
|
if (I == -1) {
|
|
Path.pop();
|
|
continue;
|
|
}
|
|
if (I == Arr->ParamTypes.size()) {
|
|
I = -1;
|
|
Ty = Arr->ReturnType;
|
|
} else {
|
|
Ty = Arr->ParamTypes[I];
|
|
I++;
|
|
}
|
|
if (llvm::isa<TArrow>(Ty)) {
|
|
Path.push({ static_cast<TArrow*>(Ty), 0 });
|
|
} else {
|
|
return Ty;
|
|
}
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
};
|
|
|
|
void Checker::solveCEqual(CEqual* C) {
|
|
/* std::cerr << describe(C->Left) << " ~ " << describe(C->Right) << std::endl; */
|
|
if (!unify(C->Left, C->Right, C->Source)) {
|
|
DE.add<UnificationErrorDiagnostic>(C->Left->substitute(Solution), C->Right->substitute(Solution), C->Source);
|
|
}
|
|
}
|
|
|
|
bool Checker::unify(Type* A, Type* B, Node* Source) {
|
|
|
|
auto find = [&](auto Ty) {
|
|
while (Ty->getKind() == TypeKind::Var) {
|
|
auto Match = Solution.find(static_cast<TVar*>(Ty));
|
|
if (Match == Solution.end()) {
|
|
break;
|
|
}
|
|
Ty = Match->second;
|
|
}
|
|
return Ty;
|
|
};
|
|
|
|
A = find(A);
|
|
B = find(B);
|
|
|
|
if (llvm::isa<TVar>(A) && llvm::isa<TVar>(B)) {
|
|
auto Var1 = static_cast<TVar*>(A);
|
|
auto Var2 = static_cast<TVar*>(B);
|
|
if (Var1->getVarKind() == VarKind::Rigid && Var2->getVarKind() == VarKind::Rigid) {
|
|
if (Var1->Id != Var2->Id) {
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
TVar* Dest;
|
|
TVar* From;
|
|
if (Var1->getVarKind() == VarKind::Rigid && Var2->getVarKind() == VarKind::Unification) {
|
|
Dest = Var1;
|
|
From = Var2;
|
|
} else {
|
|
// Only cases left are Var1 = Unification, Var2 = Rigid and Var1 = Unification, Var2 = Unification
|
|
// Either way, Var1 is a good candidate for being unified away
|
|
Dest = Var2;
|
|
From = Var1;
|
|
}
|
|
Solution[From] = Dest;
|
|
propagateClasses(From->Contexts, Dest, Source);
|
|
return true;
|
|
}
|
|
|
|
if (llvm::isa<TVar>(A)) {
|
|
auto TV = static_cast<TVar*>(A);
|
|
if (TV->getVarKind() == VarKind::Rigid) {
|
|
return false;
|
|
}
|
|
// Occurs check
|
|
if (B->hasTypeVar(TV)) {
|
|
// NOTE Just like GHC, we just display an error message indicating that
|
|
// A cannot match B, e.g. a cannot match [a]. It looks much better
|
|
// than obsure references to an occurs check
|
|
return false;
|
|
}
|
|
Solution[TV] = B;
|
|
if (!TV->Contexts.empty()) {
|
|
propagateClasses(TV->Contexts, B, Source);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
if (llvm::isa<TVar>(B)) {
|
|
return unify(B, A, Source);
|
|
}
|
|
|
|
if (llvm::isa<TArrow>(A) && llvm::isa<TArrow>(B)) {
|
|
auto C1 = ArrowCursor(static_cast<TArrow*>(A));
|
|
auto C2 = ArrowCursor(static_cast<TArrow*>(B));
|
|
for (;;) {
|
|
auto T1 = C1.next();
|
|
auto T2 = C2.next();
|
|
if (T1 == nullptr && T2 == nullptr) {
|
|
break;
|
|
}
|
|
if (T1 == nullptr || T2 == nullptr) {
|
|
return false;
|
|
}
|
|
if (!unify(T1, T2, Source)) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
/* if (Arr1->ParamTypes.size() != Arr2->ParamTypes.size()) { */
|
|
/* return false; */
|
|
/* } */
|
|
/* auto Count = Arr1->ParamTypes.size(); */
|
|
/* for (std::size_t I = 0; I < Count; I++) { */
|
|
/* if (!unify(Arr1->ParamTypes[I], Arr2->ParamTypes[I], Solution)) { */
|
|
/* return false; */
|
|
/* } */
|
|
/* } */
|
|
/* return unify(Arr1->ReturnType, Arr2->ReturnType, Solution); */
|
|
}
|
|
|
|
if (llvm::isa<TArrow>(A)) {
|
|
auto Arr = static_cast<TArrow*>(A);
|
|
if (Arr->ParamTypes.empty()) {
|
|
return unify(Arr->ReturnType, B, Source);
|
|
}
|
|
}
|
|
|
|
if (llvm::isa<TArrow>(B)) {
|
|
return unify(B, A, Source);
|
|
}
|
|
|
|
if (llvm::isa<TTuple>(A) && llvm::isa<TTuple>(B)) {
|
|
auto Tuple1 = static_cast<TTuple*>(A);
|
|
auto Tuple2 = static_cast<TTuple*>(B);
|
|
if (Tuple1->ElementTypes.size() != Tuple2->ElementTypes.size()) {
|
|
return false;
|
|
}
|
|
auto Count = Tuple1->ElementTypes.size();
|
|
bool Success = true;
|
|
for (size_t I = 0; I < Count; I++) {
|
|
if (!unify(Tuple1->ElementTypes[I], Tuple2->ElementTypes[I], Source)) {
|
|
Success = false;
|
|
}
|
|
}
|
|
return Success;
|
|
}
|
|
|
|
if (llvm::isa<TCon>(A) && llvm::isa<TCon>(B)) {
|
|
auto Con1 = static_cast<TCon*>(A);
|
|
auto Con2 = static_cast<TCon*>(B);
|
|
if (Con1->Id != Con2->Id) {
|
|
return false;
|
|
}
|
|
ZEN_ASSERT(Con1->Args.size() == Con2->Args.size());
|
|
auto Count = Con1->Args.size();
|
|
for (std::size_t I = 0; I < Count; I++) {
|
|
if (!unify(Con1->Args[I], Con2->Args[I], Source)) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
InferContext* Checker::lookupCall(Node* Source, SymbolPath Path) {
|
|
auto Def = Source->getScope()->lookup(Path);
|
|
auto Match = CallGraph.find(Def);
|
|
if (Match == CallGraph.end()) {
|
|
return nullptr;
|
|
}
|
|
return Match->second;
|
|
}
|
|
|
|
Type* Checker::getType(TypedNode *Node) {
|
|
return Node->getType()->substitute(Solution);
|
|
}
|
|
|
|
}
|
|
|