source: src/GenPoly/GenPoly.cc @ eba9d27

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// GenPoly.cc --
//
// Author           : Richard C. Bilson
// Created On       : Mon May 18 07:44:20 2015
// Last Modified By : Peter A. Buhr
// Last Modified On : Wed Jun 29 21:45:53 2016
// Update Count     : 14
//

#include "GenPoly.h"

#include <cassert>                      // for assertf, assert
#include <iostream>                     // for operator<<, ostream, basic_os...
#include <iterator>                     // for back_insert_iterator, back_in...
#include <list>                         // for list, _List_iterator, list<>:...
#include <typeindex>                    // for type_index
#include <utility>                      // for pair
#include <vector>                       // for vector

#include "AST/Type.hpp"
#include "GenPoly/ErasableScopedMap.h"  // for ErasableScopedMap<>::const_it...
#include "ResolvExpr/typeops.h"         // for flatten
#include "SynTree/Constant.h"           // for Constant
#include "SynTree/Expression.h"         // for Expression, TypeExpr, Constan...
#include "SynTree/Type.h"               // for Type, StructInstType, UnionIn...
#include "SynTree/TypeSubstitution.h"   // for TypeSubstitution

using namespace std;

namespace GenPoly {
        namespace {
                /// Checks a parameter list for polymorphic parameters; will substitute according to env if present
                bool hasPolyParams( std::list< Expression* >& params, const TypeSubstitution *env ) {
                        for ( std::list< Expression* >::iterator param = params.begin(); param != params.end(); ++param ) {
                                TypeExpr *paramType = dynamic_cast< TypeExpr* >( *param );
                                assertf(paramType, "Aggregate parameters should be type expressions");
                                if ( isPolyType( paramType->get_type(), env ) ) return true;
                        }
                        return false;
                }

                bool hasPolyParams( const std::vector<ast::ptr<ast::Expr>> & params, const ast::TypeSubstitution * env) {
                        for (auto &param : params) {
                                auto paramType = param.strict_as<ast::TypeExpr>();
                                if (isPolyType(paramType->type, env)) return true;
                        }
                        return false;
                }

                /// Checks a parameter list for polymorphic parameters from tyVars; will substitute according to env if present
                bool hasPolyParams( std::list< Expression* >& params, const TyVarMap &tyVars, const TypeSubstitution *env ) {
                        for ( std::list< Expression* >::iterator param = params.begin(); param != params.end(); ++param ) {
                                TypeExpr *paramType = dynamic_cast< TypeExpr* >( *param );
                                assertf(paramType, "Aggregate parameters should be type expressions");
                                if ( isPolyType( paramType->get_type(), tyVars, env ) ) return true;
                        }
                        return false;
                }

                __attribute__((ununsed))
                bool hasPolyParams( const std::vector<ast::ptr<ast::Expr>> & params, const TyVarMap & tyVars, const ast::TypeSubstitution * env) {
                        for (auto &param : params) {
                                auto paramType = param.strict_as<ast::TypeExpr>();
                                if (isPolyType(paramType->type, tyVars, env)) return true;
                        }
                        return false;
                }

                /// Checks a parameter list for dynamic-layout parameters from tyVars; will substitute according to env if present
                bool hasDynParams( std::list< Expression* >& params, const TyVarMap &tyVars, const TypeSubstitution *env ) {
                        for ( std::list< Expression* >::iterator param = params.begin(); param != params.end(); ++param ) {
                                TypeExpr *paramType = dynamic_cast< TypeExpr* >( *param );
                                assertf(paramType, "Aggregate parameters should be type expressions");
                                if ( isDynType( paramType->get_type(), tyVars, env ) ) return true;
                        }
                        return false;
                }

                /// Checks a parameter list for inclusion of polymorphic parameters; will substitute according to env if present
                bool includesPolyParams( std::list< Expression* >& params, const TypeSubstitution *env ) {
                        for ( std::list< Expression* >::iterator param = params.begin(); param != params.end(); ++param ) {
                                TypeExpr *paramType = dynamic_cast< TypeExpr* >( *param );
                                assertf(paramType, "Aggregate parameters should be type expressions");
                                if ( includesPolyType( paramType->get_type(), env ) ) return true;
                        }
                        return false;
                }

                /// Checks a parameter list for inclusion of polymorphic parameters from tyVars; will substitute according to env if present
                bool includesPolyParams( std::list< Expression* >& params, const TyVarMap &tyVars, const TypeSubstitution *env ) {
                        for ( std::list< Expression* >::iterator param = params.begin(); param != params.end(); ++param ) {
                                TypeExpr *paramType = dynamic_cast< TypeExpr* >( *param );
                                assertf(paramType, "Aggregate parameters should be type expressions");
                                if ( includesPolyType( paramType->get_type(), tyVars, env ) ) return true;
                        }
                        return false;
                }
        }

        Type* replaceTypeInst( Type* type, const TypeSubstitution* env ) {
                if ( ! env ) return type;
                if ( TypeInstType *typeInst = dynamic_cast< TypeInstType* >( type ) ) {
                        Type *newType = env->lookup( typeInst->get_name() );
                        if ( newType ) return newType;
                }
                return type;
        }

        const ast::Type * replaceTypeInst(const ast::Type * type, const ast::TypeSubstitution * env) {
                if (!env) return type;
                if (auto typeInst = dynamic_cast<const ast::TypeInstType*> (type)) {
                        auto newType = env->lookup(typeInst);
                        if (newType) return newType;
                }
                return type;
        }

        Type *isPolyType( Type *type, const TypeSubstitution *env ) {
                type = replaceTypeInst( type, env );

                if ( dynamic_cast< TypeInstType * >( type ) ) {
                        return type;
                } else if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
                        return isPolyType( arrayType->base, env );
                } else if ( StructInstType *structType = dynamic_cast< StructInstType* >( type ) ) {
                        if ( hasPolyParams( structType->get_parameters(), env ) ) return type;
                } else if ( UnionInstType *unionType = dynamic_cast< UnionInstType* >( type ) ) {
                        if ( hasPolyParams( unionType->get_parameters(), env ) ) return type;
                }
                return 0;
        }

        const ast::Type * isPolyType(const ast::Type * type, const ast::TypeSubstitution * env) {
                type = replaceTypeInst( type, env );

                if ( dynamic_cast< const ast::TypeInstType * >( type ) ) {
                        return type;
                } else if ( auto arrayType = dynamic_cast< const ast::ArrayType * >( type ) ) {
                        return isPolyType( arrayType->base, env );
                } else if ( auto structType = dynamic_cast< const ast::StructInstType* >( type ) ) {
                        if ( hasPolyParams( structType->params, env ) ) return type;
                } else if ( auto unionType = dynamic_cast< const ast::UnionInstType* >( type ) ) {
                        if ( hasPolyParams( unionType->params, env ) ) return type;
                }
                return 0;
        }

        Type *isPolyType( Type *type, const TyVarMap &tyVars, const TypeSubstitution *env ) {
                type = replaceTypeInst( type, env );

                if ( TypeInstType *typeInst = dynamic_cast< TypeInstType * >( type ) ) {
                        if ( tyVars.find( typeInst->get_name() ) != tyVars.end() ) {
                                return type;
                        }
                } else if ( ArrayType * arrayType = dynamic_cast< ArrayType * >( type ) ) {
                        return isPolyType( arrayType->base, tyVars, env );
                } else if ( StructInstType *structType = dynamic_cast< StructInstType* >( type ) ) {
                        if ( hasPolyParams( structType->get_parameters(), tyVars, env ) ) return type;
                } else if ( UnionInstType *unionType = dynamic_cast< UnionInstType* >( type ) ) {
                        if ( hasPolyParams( unionType->get_parameters(), tyVars, env ) ) return type;
                }
                return 0;
        }

        const ast::Type * isPolyType(const ast::Type * type, const TyVarMap & tyVars, const ast::TypeSubstitution * env) {
                type = replaceTypeInst( type, env );

                if ( auto typeInst = dynamic_cast< const ast::TypeInstType * >( type ) ) {
                        return tyVars.find(typeInst->typeString()) != tyVars.end() ? type : nullptr;
                } else if ( auto arrayType = dynamic_cast< const ast::ArrayType * >( type ) ) {
                        return isPolyType( arrayType->base, env );
                } else if ( auto structType = dynamic_cast< const ast::StructInstType* >( type ) ) {
                        if ( hasPolyParams( structType->params, env ) ) return type;
                } else if ( auto unionType = dynamic_cast< const ast::UnionInstType* >( type ) ) {
                        if ( hasPolyParams( unionType->params, env ) ) return type;
                }
                return nullptr;
        }

        ReferenceToType *isDynType( Type *type, const TyVarMap &tyVars, const TypeSubstitution *env ) {
                type = replaceTypeInst( type, env );

                if ( TypeInstType *typeInst = dynamic_cast< TypeInstType * >( type ) ) {
                        auto var = tyVars.find( typeInst->get_name() );
                        if ( var != tyVars.end() && var->second.isComplete ) {
                                return typeInst;
                        }
                } else if ( StructInstType *structType = dynamic_cast< StructInstType* >( type ) ) {
                        if ( hasDynParams( structType->get_parameters(), tyVars, env ) ) return structType;
                } else if ( UnionInstType *unionType = dynamic_cast< UnionInstType* >( type ) ) {
                        if ( hasDynParams( unionType->get_parameters(), tyVars, env ) ) return unionType;
                }
                return 0;
        }

        ReferenceToType *isDynRet( FunctionType *function, const TyVarMap &forallTypes ) {
                if ( function->get_returnVals().empty() ) return 0;

                return (ReferenceToType*)isDynType( function->get_returnVals().front()->get_type(), forallTypes );
        }

        ReferenceToType *isDynRet( FunctionType *function ) {
                if ( function->get_returnVals().empty() ) return 0;

                TyVarMap forallTypes( TypeDecl::Data{} );
                makeTyVarMap( function, forallTypes );
                return (ReferenceToType*)isDynType( function->get_returnVals().front()->get_type(), forallTypes );
        }

        bool needsAdapter( FunctionType *adaptee, const TyVarMap &tyVars ) {
//              if ( ! adaptee->get_returnVals().empty() && isPolyType( adaptee->get_returnVals().front()->get_type(), tyVars ) ) {
//                      return true;
//              } // if
                if ( isDynRet( adaptee, tyVars ) ) return true;

                for ( std::list< DeclarationWithType* >::const_iterator innerArg = adaptee->get_parameters().begin(); innerArg != adaptee->get_parameters().end(); ++innerArg ) {
//                      if ( isPolyType( (*innerArg)->get_type(), tyVars ) ) {
                        if ( isDynType( (*innerArg)->get_type(), tyVars ) ) {
                                return true;
                        } // if
                } // for
                return false;
        }

        Type *isPolyPtr( Type *type, const TypeSubstitution *env ) {
                type = replaceTypeInst( type, env );

                if ( PointerType *ptr = dynamic_cast< PointerType *>( type ) ) {
                        return isPolyType( ptr->get_base(), env );
                }
                return 0;
        }

        Type *isPolyPtr( Type *type, const TyVarMap &tyVars, const TypeSubstitution *env ) {
                type = replaceTypeInst( type, env );

                if ( PointerType *ptr = dynamic_cast< PointerType *>( type ) ) {
                        return isPolyType( ptr->get_base(), tyVars, env );
                }
                return 0;
        }

        Type * hasPolyBase( Type *type, int *levels, const TypeSubstitution *env ) {
                int dummy;
                if ( ! levels ) { levels = &dummy; }
                *levels = 0;

                while ( true ) {
                        type = replaceTypeInst( type, env );

                        if ( PointerType *ptr = dynamic_cast< PointerType *>( type ) ) {
                                type = ptr->get_base();
                                ++(*levels);
                        } else break;
                }

                return isPolyType( type, env );
        }

        Type * hasPolyBase( Type *type, const TyVarMap &tyVars, int *levels, const TypeSubstitution *env ) {
                int dummy;
                if ( ! levels ) { levels = &dummy; }
                *levels = 0;

                while ( true ) {
                        type = replaceTypeInst( type, env );

                        if ( PointerType *ptr = dynamic_cast< PointerType *>( type ) ) {
                                type = ptr->get_base();
                                ++(*levels);
                        } else break;
                }

                return isPolyType( type, tyVars, env );
        }

        bool includesPolyType( Type *type, const TypeSubstitution *env ) {
                type = replaceTypeInst( type, env );

                if ( dynamic_cast< TypeInstType * >( type ) ) {
                        return true;
                } else if ( PointerType *pointerType = dynamic_cast< PointerType* >( type ) ) {
                        if ( includesPolyType( pointerType->get_base(), env ) ) return true;
                } else if ( StructInstType *structType = dynamic_cast< StructInstType* >( type ) ) {
                        if ( includesPolyParams( structType->get_parameters(), env ) ) return true;
                } else if ( UnionInstType *unionType = dynamic_cast< UnionInstType* >( type ) ) {
                        if ( includesPolyParams( unionType->get_parameters(), env ) ) return true;
                }
                return false;
        }

        bool includesPolyType( Type *type, const TyVarMap &tyVars, const TypeSubstitution *env ) {
                type = replaceTypeInst( type, env );

                if ( TypeInstType *typeInstType = dynamic_cast< TypeInstType * >( type ) ) {
                        if ( tyVars.find( typeInstType->get_name() ) != tyVars.end() ) {
                                return true;
                        }
                } else if ( PointerType *pointerType = dynamic_cast< PointerType* >( type ) ) {
                        if ( includesPolyType( pointerType->get_base(), tyVars, env ) ) return true;
                } else if ( StructInstType *structType = dynamic_cast< StructInstType* >( type ) ) {
                        if ( includesPolyParams( structType->get_parameters(), tyVars, env ) ) return true;
                } else if ( UnionInstType *unionType = dynamic_cast< UnionInstType* >( type ) ) {
                        if ( includesPolyParams( unionType->get_parameters(), tyVars, env ) ) return true;
                }
                return false;
        }

        FunctionType * getFunctionType( Type *ty ) {
                PointerType *ptrType;
                if ( ( ptrType = dynamic_cast< PointerType* >( ty ) ) ) {
                        return dynamic_cast< FunctionType* >( ptrType->get_base() ); // pointer if FunctionType, NULL otherwise
                } else {
                        return dynamic_cast< FunctionType* >( ty ); // pointer if FunctionType, NULL otherwise
                }
        }

        const ast::FunctionType * getFunctionType( const ast::Type * ty ) {
                if ( auto pty = dynamic_cast< const ast::PointerType * >( ty ) ) {
                        return pty->base.as< ast::FunctionType >();
                } else {
                        return dynamic_cast< const ast::FunctionType * >( ty );
                }
        }

        VariableExpr * getBaseVar( Expression *expr, int *levels ) {
                int dummy;
                if ( ! levels ) { levels = &dummy; }
                *levels = 0;

                while ( true ) {
                        if ( VariableExpr *varExpr = dynamic_cast< VariableExpr* >( expr ) ) {
                                return varExpr;
                        } else if ( MemberExpr *memberExpr = dynamic_cast< MemberExpr* >( expr ) ) {
                                expr = memberExpr->get_aggregate();
                        } else if ( AddressExpr *addressExpr = dynamic_cast< AddressExpr* >( expr ) ) {
                                expr = addressExpr->get_arg();
                        } else if ( UntypedExpr *untypedExpr = dynamic_cast< UntypedExpr* >( expr ) ) {
                                // look for compiler-inserted dereference operator
                                NameExpr *fn = dynamic_cast< NameExpr* >( untypedExpr->get_function() );
                                if ( ! fn || fn->get_name() != std::string("*?") ) return 0;
                                expr = *untypedExpr->begin_args();
                        } else if ( CommaExpr *commaExpr = dynamic_cast< CommaExpr* >( expr ) ) {
                                // copy constructors insert comma exprs, look at second argument which contains the variable
                                expr = commaExpr->get_arg2();
                                continue;
                        } else if ( ConditionalExpr * condExpr = dynamic_cast< ConditionalExpr * >( expr ) ) {
                                int lvl1;
                                int lvl2;
                                VariableExpr * var1 = getBaseVar( condExpr->get_arg2(), &lvl1 );
                                VariableExpr * var2 = getBaseVar( condExpr->get_arg3(), &lvl2 );
                                if ( lvl1 == lvl2 && var1 && var2 && var1->get_var() == var2->get_var() ) {
                                        *levels = lvl1;
                                        return var1;
                                }
                                break;
                        } else break;

                        ++(*levels);
                }

                return 0;
        }

        namespace {
                /// Checks if is a pointer to D
                template<typename D, typename B>
                bool is( const B* p ) { return type_index{typeid(D)} == type_index{typeid(*p)}; }

                /// Converts to a pointer to D without checking for safety
                template<typename D, typename B>
                inline D* as( B* p ) { return reinterpret_cast<D*>(p); }

                /// Flattens a declaration list
                template<typename Output>
                void flattenList( list< DeclarationWithType* > src, Output out ) {
                        for ( DeclarationWithType* decl : src ) {
                                ResolvExpr::flatten( decl->get_type(), out );
                        }
                }

                /// Flattens a list of types
                template<typename Output>
                void flattenList( list< Type* > src, Output out ) {
                        for ( Type* ty : src ) {
                                ResolvExpr::flatten( ty, out );
                        }
                }

                /// Checks if two lists of parameters are equal up to polymorphic substitution.
                bool paramListsPolyCompatible( const list< Expression* >& aparams, const list< Expression* >& bparams ) {
                        if ( aparams.size() != bparams.size() ) return false;

                        for ( list< Expression* >::const_iterator at = aparams.begin(), bt = bparams.begin();
                                        at != aparams.end(); ++at, ++bt ) {
                                TypeExpr *aparam = dynamic_cast< TypeExpr* >(*at);
                                assertf(aparam, "Aggregate parameters should be type expressions");
                                TypeExpr *bparam = dynamic_cast< TypeExpr* >(*bt);
                                assertf(bparam, "Aggregate parameters should be type expressions");

                                // xxx - might need to let VoidType be a wildcard here too; could have some voids
                                // stuffed in for dtype-statics.
                                // if ( is<VoidType>( aparam->get_type() ) || is<VoidType>( bparam->get_type() ) ) continue;
                                if ( ! typesPolyCompatible( aparam->get_type(), bparam->get_type() ) ) return false;
                        }

                        return true;
                }
        }

        bool typesPolyCompatible( Type *a, Type *b ) {
                type_index aid{ typeid(*a) };
                // polymorphic types always match
                if ( aid == type_index{typeid(TypeInstType)} ) return true;

                type_index bid{ typeid(*b) };
                // polymorphic types always match
                if ( bid == type_index{typeid(TypeInstType)} ) return true;

                // can't match otherwise if different types
                if ( aid != bid ) return false;

                // recurse through type structure (conditions borrowed from Unify.cc)
                if ( aid == type_index{typeid(BasicType)} ) {
                        return as<BasicType>(a)->get_kind() == as<BasicType>(b)->get_kind();
                } else if ( aid == type_index{typeid(PointerType)} ) {
                        PointerType *ap = as<PointerType>(a), *bp = as<PointerType>(b);

                        // void pointers should match any other pointer type
                        return is<VoidType>( ap->get_base() ) || is<VoidType>( bp->get_base() )
                                || typesPolyCompatible( ap->get_base(), bp->get_base() );
                } else if ( aid == type_index{typeid(ReferenceType)} ) {
                        ReferenceType *ap = as<ReferenceType>(a), *bp = as<ReferenceType>(b);
                        return is<VoidType>( ap->get_base() ) || is<VoidType>( bp->get_base() )
                                || typesPolyCompatible( ap->get_base(), bp->get_base() );
                } else if ( aid == type_index{typeid(ArrayType)} ) {
                        ArrayType *aa = as<ArrayType>(a), *ba = as<ArrayType>(b);

                        if ( aa->get_isVarLen() ) {
                                if ( ! ba->get_isVarLen() ) return false;
                        } else {
                                if ( ba->get_isVarLen() ) return false;

                                ConstantExpr *ad = dynamic_cast<ConstantExpr*>( aa->get_dimension() );
                                ConstantExpr *bd = dynamic_cast<ConstantExpr*>( ba->get_dimension() );
                                if ( ad && bd
                                                && ad->get_constant()->get_value() != bd->get_constant()->get_value() )
                                        return false;
                        }

                        return typesPolyCompatible( aa->get_base(), ba->get_base() );
                } else if ( aid == type_index{typeid(FunctionType)} ) {
                        FunctionType *af = as<FunctionType>(a), *bf = as<FunctionType>(b);

                        vector<Type*> aparams, bparams;
                        flattenList( af->get_parameters(), back_inserter( aparams ) );
                        flattenList( bf->get_parameters(), back_inserter( bparams ) );
                        if ( aparams.size() != bparams.size() ) return false;

                        vector<Type*> areturns, breturns;
                        flattenList( af->get_returnVals(), back_inserter( areturns ) );
                        flattenList( bf->get_returnVals(), back_inserter( breturns ) );
                        if ( areturns.size() != breturns.size() ) return false;

                        for ( unsigned i = 0; i < aparams.size(); ++i ) {
                                if ( ! typesPolyCompatible( aparams[i], bparams[i] ) ) return false;
                        }
                        for ( unsigned i = 0; i < areturns.size(); ++i ) {
                                if ( ! typesPolyCompatible( areturns[i], breturns[i] ) ) return false;
                        }
                        return true;
                } else if ( aid == type_index{typeid(StructInstType)} ) {
                        StructInstType *aa = as<StructInstType>(a), *ba = as<StructInstType>(b);

                        if ( aa->get_name() != ba->get_name() ) return false;
                        return paramListsPolyCompatible( aa->get_parameters(), ba->get_parameters() );
                } else if ( aid == type_index{typeid(UnionInstType)} ) {
                        UnionInstType *aa = as<UnionInstType>(a), *ba = as<UnionInstType>(b);

                        if ( aa->get_name() != ba->get_name() ) return false;
                        return paramListsPolyCompatible( aa->get_parameters(), ba->get_parameters() );
                } else if ( aid == type_index{typeid(EnumInstType)} ) {
                        return as<EnumInstType>(a)->get_name() == as<EnumInstType>(b)->get_name();
                } else if ( aid == type_index{typeid(TraitInstType)} ) {
                        return as<TraitInstType>(a)->get_name() == as<TraitInstType>(b)->get_name();
                } else if ( aid == type_index{typeid(TupleType)} ) {
                        TupleType *at = as<TupleType>(a), *bt = as<TupleType>(b);

                        vector<Type*> atypes, btypes;
                        flattenList( at->get_types(), back_inserter( atypes ) );
                        flattenList( bt->get_types(), back_inserter( btypes ) );
                        if ( atypes.size() != btypes.size() ) return false;

                        for ( unsigned i = 0; i < atypes.size(); ++i ) {
                                if ( ! typesPolyCompatible( atypes[i], btypes[i] ) ) return false;
                        }
                        return true;
                } else return true; // VoidType, VarArgsType, ZeroType & OneType just need the same type
        }

        namespace {
                // temporary hack to avoid re-implementing anything related to TyVarMap
                // does this work? these two structs have identical definitions.
                inline TypeDecl::Data convData(const ast::TypeDecl::Data & data) {
                        return *reinterpret_cast<const TypeDecl::Data *>(&data);
                }
        }

        bool needsBoxing( Type * param, Type * arg, const TyVarMap &exprTyVars, const TypeSubstitution * env ) {
                // is parameter is not polymorphic, don't need to box
                if ( ! isPolyType( param, exprTyVars ) ) return false;
                Type * newType = arg->clone();
                if ( env ) env->apply( newType );
                std::unique_ptr<Type> manager( newType );
                // if the argument's type is polymorphic, we don't need to box again!
                return ! isPolyType( newType );
        }

        bool needsBoxing( const ast::Type * param, const ast::Type * arg, const TyVarMap &exprTyVars, const ast::TypeSubstitution * env) {
                // is parameter is not polymorphic, don't need to box
                if ( ! isPolyType( param, exprTyVars ) ) return false;
                ast::ptr<ast::Type> newType = arg;
                if ( env ) env->apply( newType );
                // if the argument's type is polymorphic, we don't need to box again!
                return ! isPolyType( newType );
        }

        bool needsBoxing( Type * param, Type * arg, ApplicationExpr * appExpr, const TypeSubstitution * env ) {
                FunctionType * function = getFunctionType( appExpr->function->result );
                assertf( function, "ApplicationExpr has non-function type: %s", toString( appExpr->function->result ).c_str() );
                TyVarMap exprTyVars( TypeDecl::Data{} );
                makeTyVarMap( function, exprTyVars );
                return needsBoxing( param, arg, exprTyVars, env );
        }

        bool needsBoxing( const ast::Type * param, const ast::Type * arg, const ast::ApplicationExpr * appExpr, const ast::TypeSubstitution * env) {
                const ast::FunctionType * function = getFunctionType(appExpr->func->result);
                assertf( function, "ApplicationExpr has non-function type: %s", toString( appExpr->func->result ).c_str() );
                TyVarMap exprTyVars(TypeDecl::Data{});
                makeTyVarMap(function, exprTyVars);
                return needsBoxing(param, arg, exprTyVars, env);

        }

        void addToTyVarMap( TypeDecl * tyVar, TyVarMap &tyVarMap ) {
                tyVarMap.insert( tyVar->name, TypeDecl::Data{ tyVar } );
        }

        void addToTyVarMap( const ast::TypeInstType * tyVar, TyVarMap & tyVarMap) {
                tyVarMap.insert(tyVar->typeString(), convData(ast::TypeDecl::Data{tyVar->base}));
        }

        void makeTyVarMap( Type *type, TyVarMap &tyVarMap ) {
                for ( Type::ForallList::const_iterator tyVar = type->get_forall().begin(); tyVar != type->get_forall().end(); ++tyVar ) {
                        assert( *tyVar );
                        addToTyVarMap( *tyVar, tyVarMap );
                }
                if ( PointerType *pointer = dynamic_cast< PointerType* >( type ) ) {
                        makeTyVarMap( pointer->get_base(), tyVarMap );
                }
        }

        void makeTyVarMap(const ast::Type * type, TyVarMap & tyVarMap) {
                if (auto ptype = dynamic_cast<const ast::FunctionType *>(type)) {
                        for (auto & tyVar : ptype->forall) {
                                assert (tyVar);
                                addToTyVarMap(tyVar, tyVarMap);
                        }
                }
                if (auto pointer = dynamic_cast<const ast::PointerType *>(type)) {
                        makeTyVarMap(pointer->base, tyVarMap);
                }
        }

        void printTyVarMap( std::ostream &os, const TyVarMap &tyVarMap ) {
                for ( TyVarMap::const_iterator i = tyVarMap.begin(); i != tyVarMap.end(); ++i ) {
                        os << i->first << " (" << i->second << ") ";
                } // for
                os << std::endl;
        }

} // namespace GenPoly

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //