Changeset d286cf68

Timestamp:

Jun 26, 2018, 5:16:19 PM (6 years ago)

Author:

Aaron Moss <a3moss@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, with_gc

Children:

63238a4

Parents:

270fdcf

Message:

Fix TypeEnvironment? bind algorithms

Location:

src/ResolvExpr

Files:

• AlternativeFinder.cc (modified) (1 diff)
• CommonType.cc (modified) (2 diffs)
• ExplodedActual.h (modified) (1 diff)
• Resolver.cc (modified) (1 diff)
• TypeEnvironment.cc (modified) (14 diffs)
• TypeEnvironment.h (modified) (6 diffs)
• Unify.cc (modified) (3 diffs)
• Unify.h (modified) (3 diffs)
• WidenMode.h (added)

src/ResolvExpr/AlternativeFinder.cc

@@ -1099 +1099 @@
                         argExpansions.emplace_back();
                         auto& argE = argExpansions.back();
-                        argE.reserve( arg.alternatives.size() );
+                        // argE.reserve( arg.alternatives.size() );
 
                         for ( const Alternative& actual : arg ) {

src/ResolvExpr/CommonType.cc

@@ -24 +24 @@
 #include "SynTree/Type.h"                // for BasicType, BasicType::Kind::...
 #include "SynTree/Visitor.h"             // for Visitor
-#include "Unify.h"                       // for unifyExact, bindVar, WidenMode
+#include "Unify.h"                       // for unifyExact, WidenMode
 #include "typeops.h"                     // for isFtype
 
@@ -238 +238 @@
                                 AssertionSet need, have;
                                 WidenMode widen( widenFirst, widenSecond );
-                                if ( entry != openVars.end() && ! bindVar(var, voidPointer->get_base(), entry->second, env, need, have, openVars, widen, indexer ) ) return;
+                                if ( entry != openVars.end() && ! env.bindVar(var, voidPointer->get_base(), entry->second, need, have, openVars, widen, indexer ) ) return;
                         }
                 }

src/ResolvExpr/ExplodedActual.h

@@ -32 +32 @@
 
                 ExplodedActual() : env(), cost(Cost::zero), exprs() {}
-
                 ExplodedActual( const Alternative& actual, const SymTab::Indexer& indexer );
+                ExplodedActual(ExplodedActual&&) = default;
+                ExplodedActual& operator= (ExplodedActual&&) = default;
         };
 }

src/ResolvExpr/Resolver.cc

@@ -582 +582 @@
 
                                                         // Make sure we don't widen any existing bindings
-                                                        for ( auto & i : resultEnv ) {
-                                                                i.allowWidening = false;
-                                                        }
-
+                                                        resultEnv.forbidWidening();
+                                                        
                                                         // Find any unbound type variables
                                                         resultEnv.extractOpenVars( openVars );

src/ResolvExpr/TypeEnvironment.cc

@@ -9 +9 @@
 // Author           : Richard C. Bilson
 // Created On       : Sun May 17 12:19:47 2015
-// Last Modified By : Peter A. Buhr
-// Last Modified On : Sun May 17 12:23:36 2015
-// Update Count     : 3
+// Last Modified By : Aaron B. Moss
+// Last Modified On : Mon Jun 18 11:58:00 2018
+// Update Count     : 4
 //
 
@@ -17 +17 @@
 #include <algorithm>                   // for copy, set_intersection
 #include <iterator>                    // for ostream_iterator, insert_iterator
+#include <memory>                      // for unique_ptr
 #include <utility>                     // for pair, move
 
@@ -22 +23 @@
 #include "SynTree/Type.h"              // for Type, FunctionType, Type::Fora...
 #include "SynTree/TypeSubstitution.h"  // for TypeSubstitution
+#include "Tuples/Tuples.h"             // for isTtype
 #include "TypeEnvironment.h"
+#include "typeops.h"                   // for occurs
+#include "Unify.h"                     // for unifyInexact
 
 namespace ResolvExpr {
@@ -65 +69 @@
         }
 
+        EqvClass::EqvClass( EqvClass &&other ) 
+        : vars{std::move(other.vars)}, type{other.type}, 
+          allowWidening{std::move(other.allowWidening)}, data{std::move(other.data)} {
+                  other.type = nullptr;
+        }
+
         EqvClass &EqvClass::operator=( const EqvClass &other ) {
                 if ( this == &other ) return *this;
@@ -72 +82 @@
         }
 
+        EqvClass &EqvClass::operator=( EqvClass &&other ) {
+                if ( this == &other ) return *this;
+                delete type;
+                
+                vars = std::move(other.vars);
+                type = other.type;
+                other.type = nullptr;
+                allowWidening = std::move(other.allowWidening);
+                data = std::move(other.data);
+
+                return *this;
+        }
+
         EqvClass::~EqvClass() {
                 delete type;
+        }
+
+        void EqvClass::set_type( Type* ty ) {
+                if ( ty == type ) return;
+                delete type;
+                type = ty;
         }
 
@@ -92 +121 @@
         const EqvClass* TypeEnvironment::lookup( const std::string &var ) const {
                 for ( std::list< EqvClass >::const_iterator i = env.begin(); i != env.end(); ++i ) {
-                        if ( i->vars.find( var ) != i->vars.end() ) {
-///       std::cout << var << " is in class ";
-///       i->print( std::cout );
-                                return &*i;
-                        }
-///     std::cout << var << " is not in class ";
-///     i->print( std::cout );
+                        if ( i->vars.find( var ) != i->vars.end() ) return &*i;
                 } // for
                 return nullptr;
@@ -116 +139 @@
         }
 
-        void TypeEnvironment::add( const EqvClass &eqvClass ) {
-                filterOverlappingClasses( env, eqvClass );
-                env.push_back( eqvClass );
-        }
-
         void TypeEnvironment::add( EqvClass &&eqvClass ) {
                 filterOverlappingClasses( env, eqvClass );
@@ -131 +149 @@
                         newClass.vars.insert( (*i)->get_name() );
                         newClass.data = TypeDecl::Data{ (*i) };
-                        env.push_back( newClass );
+                        env.push_back( std::move(newClass) );
                 } // for
         }
@@ -145 +163 @@
                         // transition to TypeSubstitution
                         newClass.data = TypeDecl::Data{ TypeDecl::Dtype, false };
-                        add( newClass );
+                        add( std::move(newClass) );
                 }
         }
@@ -152 +170 @@
                 for ( std::list< EqvClass >::const_iterator theClass = env.begin(); theClass != env.end(); ++theClass ) {
                         for ( std::set< std::string >::const_iterator theVar = theClass->vars.begin(); theVar != theClass->vars.end(); ++theVar ) {
-///       std::cerr << "adding " << *theVar;
                                 if ( theClass->type ) {
-///         std::cerr << " bound to ";
-///         theClass->type->print( std::cerr );
-///         std::cerr << std::endl;
                                         sub.add( *theVar, theClass->type );
                                 } else if ( theVar != theClass->vars.begin() ) {
                                         TypeInstType *newTypeInst = new TypeInstType( Type::Qualifiers(), *theClass->vars.begin(), theClass->data.kind == TypeDecl::Ftype );
-///         std::cerr << " bound to variable " << *theClass->vars.begin() << std::endl;
                                         sub.add( *theVar, newTypeInst );
                                         delete newTypeInst;
@@ -166 +179 @@
                         } // for
                 } // for
-///   std::cerr << "input env is:" << std::endl;
-///   print( std::cerr, 8 );
-///   std::cerr << "sub is:" << std::endl;
-///   sub.print( std::cerr, 8 );
                 sub.normalize();
         }
@@ -181 +190 @@
         std::list< EqvClass >::iterator TypeEnvironment::internal_lookup( const std::string &var ) {
                 for ( std::list< EqvClass >::iterator i = env.begin(); i != env.end(); ++i ) {
-                        if ( i->vars.find( var ) == i->vars.end() ) {
-                                return i;
-                        } // if
+                        if ( i->vars.count( var ) ) return i;
                 } // for
                 return env.end();
@@ -190 +197 @@
         void TypeEnvironment::simpleCombine( const TypeEnvironment &second ) {
                 env.insert( env.end(), second.env.begin(), second.env.end() );
-        }
-
-        void TypeEnvironment::combine( const TypeEnvironment &second, Type *(*combineFunc)( Type*, Type* ) ) {
-                TypeEnvironment secondCopy( second );
-                for ( std::list< EqvClass >::iterator firstClass = env.begin(); firstClass != env.end(); ++firstClass ) {
-                        EqvClass &newClass = *firstClass;
-                        std::set< std::string > newVars;
-                        for ( std::set< std::string >::const_iterator var = firstClass->vars.begin(); var != firstClass->vars.end(); ++var ) {
-                                std::list< EqvClass >::iterator secondClass = secondCopy.internal_lookup( *var );
-                                if ( secondClass != secondCopy.env.end() ) {
-                                        newVars.insert( secondClass->vars.begin(), secondClass->vars.end() );
-                                        if ( secondClass->type ) {
-                                                if ( newClass.type ) {
-                                                        Type *newType = combineFunc( newClass.type, secondClass->type );
-                                                        delete newClass.type;
-                                                        newClass.type = newType;
-                                                        newClass.allowWidening = newClass.allowWidening && secondClass->allowWidening;
-                                                } else {
-                                                        newClass.type = secondClass->type->clone();
-                                                        newClass.allowWidening = secondClass->allowWidening;
-                                                } // if
-                                        } // if
-                                        secondCopy.env.erase( secondClass );
-                                } // if
-                        } // for
-                        newClass.vars.insert( newVars.begin(), newVars.end() );
-                } // for
-                for ( std::list< EqvClass >::iterator secondClass = secondCopy.env.begin(); secondClass != secondCopy.env.end(); ++secondClass ) {
-                        env.push_back( *secondClass );
-                } // for
         }
 
@@ -241 +218 @@
         }
 
+        bool isFtype( Type *type ) {
+                if ( dynamic_cast< FunctionType* >( type ) ) {
+                        return true;
+                } else if ( TypeInstType *typeInst = dynamic_cast< TypeInstType* >( type ) ) {
+                        return typeInst->get_isFtype();
+                } // if
+                return false;
+        }
+
+        bool tyVarCompatible( const TypeDecl::Data & data, Type *type ) {
+                switch ( data.kind ) {
+                  case TypeDecl::Dtype:
+                        // to bind to an object type variable, the type must not be a function type.
+                        // if the type variable is specified to be a complete type then the incoming
+                        // type must also be complete
+                        // xxx - should this also check that type is not a tuple type and that it's not a ttype?
+                        return ! isFtype( type ) && (! data.isComplete || type->isComplete() );
+                  case TypeDecl::Ftype:
+                        return isFtype( type );
+                  case TypeDecl::Ttype:
+                        // ttype unifies with any tuple type
+                        return dynamic_cast< TupleType * >( type ) || Tuples::isTtype( type );
+                } // switch
+                return false;
+        }
+
+        bool TypeEnvironment::bindVar( TypeInstType *typeInst, Type *bindTo, const TypeDecl::Data & data, AssertionSet &need, AssertionSet &have, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
+                
+                // remove references from other, so that type variables can only bind to value types
+                bindTo = bindTo->stripReferences();
+                OpenVarSet::const_iterator tyvar = openVars.find( typeInst->get_name() );
+                assert( tyvar != openVars.end() );
+                if ( ! tyVarCompatible( tyvar->second, bindTo ) ) {
+                        return false;
+                } // if
+                if ( occurs( bindTo, typeInst->get_name(), *this ) ) {
+                        return false;
+                } // if
+                auto curClass = internal_lookup( typeInst->get_name() );
+                if ( curClass != env.end() ) {
+                        if ( curClass->type ) {
+                                Type *common = 0;
+                                // attempt to unify equivalence class type (which has qualifiers stripped, so they must be restored) with the type to bind to
+                                std::unique_ptr< Type > newType( curClass->type->clone() );
+                                newType->get_qualifiers() = typeInst->get_qualifiers();
+                                if ( unifyInexact( newType.get(), bindTo, *this, need, have, openVars, widenMode & WidenMode( curClass->allowWidening, true ), indexer, common ) ) {
+                                        if ( common ) {
+                                                common->get_qualifiers() = Type::Qualifiers{};
+                                                curClass->set_type( common );
+                                        } // if
+                                } else return false;
+                        } else {
+                                Type* newType = bindTo->clone();
+                                newType->get_qualifiers() = Type::Qualifiers{};
+                                curClass->set_type( newType );
+                                curClass->allowWidening = widenMode.widenFirst && widenMode.widenSecond;
+                        } // if
+                } else {
+                        EqvClass newClass;
+                        newClass.vars.insert( typeInst->get_name() );
+                        newClass.type = bindTo->clone();
+                        newClass.type->get_qualifiers() = Type::Qualifiers();
+                        newClass.allowWidening = widenMode.widenFirst && widenMode.widenSecond;
+                        newClass.data = data;
+                        env.push_back( std::move(newClass) );
+                } // if
+                return true;
+        }
+
+        bool TypeEnvironment::bindVarToVar( TypeInstType *var1, TypeInstType *var2, const TypeDecl::Data & data, AssertionSet &need, AssertionSet &have, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
+
+                auto class1 = internal_lookup( var1->get_name() );
+                auto class2 = internal_lookup( var2->get_name() );
+                
+                // exit early if variables already bound together
+                if ( class1 != env.end() && class1 == class2 ) {
+                        class1->allowWidening &= widenMode;
+                        return true;
+                }
+
+                bool widen1 = false, widen2 = false;
+                const Type *type1 = nullptr, *type2 = nullptr;
+
+                // check for existing bindings, perform occurs check
+                if ( class1 != env.end() ) {
+                        if ( class1->type ) {
+                                if ( occurs( class1->type, var2->get_name(), *this ) ) return false;
+                                type1 = class1->type;
+                        } // if
+                        widen1 = widenMode.widenFirst && class1->allowWidening;
+                } // if
+                if ( class2 != env.end() ) {
+                        if ( class2->type ) {
+                                if ( occurs( class2->type, var1->get_name(), *this ) ) return false;
+                                type2 = class2->type;
+                        } // if
+                        widen2 = widenMode.widenSecond && class2->allowWidening;
+                } // if
+
+                if ( type1 && type2 ) {
+                        // both classes bound, merge if bound types can be unified
+                        std::unique_ptr<Type> newType1{ type1->clone() }, newType2{ type2->clone() };
+                        WidenMode newWidenMode{ widen1, widen2 };
+                        Type *common = 0;
+                        if ( unifyInexact( newType1.get(), newType2.get(), *this, need, have, openVars, newWidenMode, indexer, common ) ) {
+                                class1->vars.insert( class2->vars.begin(), class2->vars.end() );
+                                class1->allowWidening = widen1 && widen2;
+                                if ( common ) {
+                                        common->get_qualifiers() = Type::Qualifiers{};
+                                        class1->set_type( common );
+                                }
+                                env.erase( class2 );
+                        } else return false;
+                } else if ( class1 != env.end() && class2 != env.end() ) {
+                        // both classes exist, at least one unbound, merge unconditionally
+                        if ( type1 ) {
+                                class1->vars.insert( class2->vars.begin(), class2->vars.end() );
+                                class1->allowWidening = widen1;
+                                env.erase( class2 );
+                        } else {
+                                class2->vars.insert( class1->vars.begin(), class1->vars.end() );
+                                class2->allowWidening = widen2;
+                                env.erase( class1 );
+                        } // if
+                } else if ( class1 != env.end() ) {
+                        // var2 unbound, add to class1
+                        class1->vars.insert( var2->get_name() );
+                        class1->allowWidening = widen1;
+                } else if ( class2 != env.end() ) {
+                        // var1 unbound, add to class2
+                        class2->vars.insert( var1->get_name() );
+                        class2->allowWidening = widen2;
+                } else {
+                        // neither var bound, create new class
+                        EqvClass newClass;
+                        newClass.vars.insert( var1->get_name() );
+                        newClass.vars.insert( var2->get_name() );
+                        newClass.allowWidening = widen1 && widen2;
+                        newClass.data = data;
+                        env.push_back( std::move(newClass) );
+                } // if
+                return true;
+        }
+
+        void TypeEnvironment::forbidWidening() {
+                for ( EqvClass& c : env ) c.allowWidening = false;
+        }
+
         std::ostream & operator<<( std::ostream & out, const TypeEnvironment & env ) {
                 env.print( out );

src/ResolvExpr/TypeEnvironment.h

@@ -9 +9 @@
 // Author           : Richard C. Bilson
 // Created On       : Sun May 17 12:24:58 2015
-// Last Modified By : Peter A. Buhr
-// Last Modified On : Sat Jul 22 09:35:45 2017
-// Update Count     : 3
+// Last Modified By : Aaron B. Moss
+// Last Modified On : Mon Jun 18 11:58:00 2018
+// Update Count     : 4
 //
 
@@ -21 +21 @@
 #include <set>                         // for set
 #include <string>                      // for string
+#include <utility>                     // for move, swap
+
+#include "WidenMode.h"                 // for WidenMode
 
 #include "SynTree/Declaration.h"       // for TypeDecl::Data, DeclarationWit...
@@ -77 +80 @@
                 EqvClass( const EqvClass &other );
                 EqvClass( const EqvClass &other, const Type *ty );
+                EqvClass( EqvClass &&other );
                 EqvClass &operator=( const EqvClass &other );
+                EqvClass &operator=( EqvClass &&other );
                 ~EqvClass();
                 void print( std::ostream &os, Indenter indent = {} ) const;
+
+                /// Takes ownership of `ty`, freeing old `type`
+                void set_type(Type* ty);
         };
 
@@ -85 +93 @@
           public:
                 const EqvClass* lookup( const std::string &var ) const;
-                void add( const EqvClass &eqvClass );
+          private:
                 void add( EqvClass &&eqvClass  );
+          public:
                 void add( const Type::ForallList &tyDecls );
                 void add( const TypeSubstitution & sub );
@@ -94 +103 @@
                 bool isEmpty() const { return env.empty(); }
                 void print( std::ostream &os, Indenter indent = {} ) const;
-                void combine( const TypeEnvironment &second, Type *(*combineFunc)( Type*, Type* ) );
+                // void combine( const TypeEnvironment &second, Type *(*combineFunc)( Type*, Type* ) );
                 void simpleCombine( const TypeEnvironment &second );
                 void extractOpenVars( OpenVarSet &openVars ) const;
@@ -103 +112 @@
                 void addActual( const TypeEnvironment& actualEnv, OpenVarSet& openVars );
 
-                typedef std::list< EqvClass >::iterator iterator;
-                iterator begin() { return env.begin(); }
-                iterator end() { return env.end(); }
-                typedef std::list< EqvClass >::const_iterator const_iterator;
-                const_iterator begin() const { return env.begin(); }
-                const_iterator end() const { return env.end(); }
+                /// Binds the type class represented by `typeInst` to the type `bindTo`; will add 
+                /// the class if needed. Returns false on failure.
+                bool bindVar( TypeInstType *typeInst, Type *bindTo, const TypeDecl::Data & data, AssertionSet &need, AssertionSet &have, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer );
+                
+                /// Binds the type classes represented by `var1` and `var2` together; will add 
+                /// one or both classes if needed. Returns false on failure.
+                bool bindVarToVar( TypeInstType *var1, TypeInstType *var2, const TypeDecl::Data & data, AssertionSet &need, AssertionSet &have, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer );
+
+                /// Disallows widening for all bindings in the environment
+                void forbidWidening();
+
+                using iterator = std::list< EqvClass >::const_iterator;
+                iterator begin() const { return env.begin(); }
+                iterator end() const { return env.end(); }
+
           private:
                 std::list< EqvClass > env;
+                
                 std::list< EqvClass >::iterator internal_lookup( const std::string &var );
         };

src/ResolvExpr/Unify.cc

@@ -9 +9 @@
 // Author           : Richard C. Bilson
 // Created On       : Sun May 17 12:27:10 2015
-// Last Modified By : Peter A. Buhr
-// Last Modified On : Thu Mar 16 16:22:54 2017
-// Update Count     : 42
+// Last Modified By : Aaron B. Moss
+// Last Modified On : Mon Jun 18 11:58:00 2018
+// Update Count     : 43
 //
 
@@ -129 +129 @@
         }
 
-        bool isFtype( Type *type ) {
-                if ( dynamic_cast< FunctionType* >( type ) ) {
-                        return true;
-                } else if ( TypeInstType *typeInst = dynamic_cast< TypeInstType* >( type ) ) {
-                        return typeInst->get_isFtype();
-                } // if
-                return false;
-        }
-
-        bool tyVarCompatible( const TypeDecl::Data & data, Type *type ) {
-                switch ( data.kind ) {
-                  case TypeDecl::Dtype:
-                        // to bind to an object type variable, the type must not be a function type.
-                        // if the type variable is specified to be a complete type then the incoming
-                        // type must also be complete
-                        // xxx - should this also check that type is not a tuple type and that it's not a ttype?
-                        return ! isFtype( type ) && (! data.isComplete || type->isComplete() );
-                  case TypeDecl::Ftype:
-                        return isFtype( type );
-                  case TypeDecl::Ttype:
-                        // ttype unifies with any tuple type
-                        return dynamic_cast< TupleType * >( type ) || Tuples::isTtype( type );
-                } // switch
-                return false;
-        }
-
-        bool bindVar( TypeInstType *typeInst, Type *other, const TypeDecl::Data & data, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
-                // remove references from other, so that type variables can only bind to value types
-                other = other->stripReferences();
-                OpenVarSet::const_iterator tyvar = openVars.find( typeInst->get_name() );
-                assert( tyvar != openVars.end() );
-                if ( ! tyVarCompatible( tyvar->second, other ) ) {
-                        return false;
-                } // if
-                if ( occurs( other, typeInst->get_name(), env ) ) {
-                        return false;
-                } // if
-                if ( const EqvClass *curClass = env.lookup( typeInst->get_name() ) ) {
-                        if ( curClass->type ) {
-                                Type *common = 0;
-                                // attempt to unify equivalence class type (which has qualifiers stripped, so they must be restored) with the type to bind to
-                                std::unique_ptr< Type > newType( curClass->type->clone() );
-                                newType->get_qualifiers() = typeInst->get_qualifiers();
-                                if ( unifyInexact( newType.get(), other, env, needAssertions, haveAssertions, openVars, widenMode & WidenMode( curClass->allowWidening, true ), indexer, common ) ) {
-                                        if ( common ) {
-                                                common->get_qualifiers() = Type::Qualifiers();
-                                                env.add( EqvClass{ *curClass, common } );
-                                        } // if
-                                        return true;
-                                } else {
-                                        return false;
-                                } // if
-                        } else {
-                                EqvClass newClass { *curClass, other };
-                                newClass.type->get_qualifiers() = Type::Qualifiers();
-                                newClass.allowWidening = widenMode.widenFirst && widenMode.widenSecond;
-                                env.add( std::move(newClass) );
-                        } // if
-                } else {
-                        EqvClass newClass;
-                        newClass.vars.insert( typeInst->get_name() );
-                        newClass.type = other->clone();
-                        newClass.type->get_qualifiers() = Type::Qualifiers();
-                        newClass.allowWidening = widenMode.widenFirst && widenMode.widenSecond;
-                        newClass.data = data;
-                        env.add( newClass );
-                } // if
-                return true;
-        }
-
-        bool bindVarToVar( TypeInstType *var1, TypeInstType *var2, const TypeDecl::Data & data, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
-                bool result = true;
-                const EqvClass *class1 = env.lookup( var1->get_name() );
-                const EqvClass *class2 = env.lookup( var2->get_name() );
-                bool widen1 = false, widen2 = false;
-                Type *type1 = nullptr, *type2 = nullptr;
-
-                if ( class1 ) {
-                        if ( class1->type ) {
-                                if ( occurs( class1->type, var2->get_name(), env ) ) {
-                                        return false;
-                                } // if
-                                type1 = class1->type->clone();
-                        } // if
-                        widen1 = widenMode.widenFirst && class1->allowWidening;
-                } // if
-                if ( class2 ) {
-                        if ( class2->type ) {
-                                if ( occurs( class2->type, var1->get_name(), env ) ) {
-                                        return false;
-                                } // if
-                                type2 = class2->type->clone();
-                        } // if
-                        widen2 = widenMode.widenSecond && class2->allowWidening;
-                } // if
-
-                if ( type1 && type2 ) {
-//    std::cerr << "has type1 && type2" << std::endl;
-                        WidenMode newWidenMode ( widen1, widen2 );
-                        Type *common = 0;
-                        if ( unifyInexact( type1, type2, env, needAssertions, haveAssertions, openVars, newWidenMode, indexer, common ) ) {
-                                EqvClass newClass1 = *class1;
-                                newClass1.vars.insert( class2->vars.begin(), class2->vars.end() );
-                                newClass1.allowWidening = widen1 && widen2;
-                                if ( common ) {
-                                        common->get_qualifiers() = Type::Qualifiers();
-                                        delete newClass1.type;
-                                        newClass1.type = common;
-                                } // if
-                                env.add( std::move(newClass1) );
-                        } else {
-                                result = false;
-                        } // if
-                } else if ( class1 && class2 ) {
-                        if ( type1 ) {
-                                EqvClass newClass1 = *class1;
-                                newClass1.vars.insert( class2->vars.begin(), class2->vars.end() );
-                                newClass1.allowWidening = widen1;
-                                env.add( std::move(newClass1) );
-                        } else {
-                                EqvClass newClass2 = *class2;
-                                newClass2.vars.insert( class1->vars.begin(), class1->vars.end() );
-                                newClass2.allowWidening = widen2;
-                                env.add( std::move(newClass2) );
-                        } // if
-                } else if ( class1 ) {
-                        EqvClass newClass1 = *class1;
-                        newClass1.vars.insert( var2->get_name() );
-                        newClass1.allowWidening = widen1;
-                        env.add( std::move(newClass1) );
-                } else if ( class2 ) {
-                        EqvClass newClass2 = *class2;
-                        newClass2.vars.insert( var1->get_name() );
-                        newClass2.allowWidening = widen2;
-                        env.add( std::move(newClass2) );
-                } else {
-                        EqvClass newClass;
-                        newClass.vars.insert( var1->get_name() );
-                        newClass.vars.insert( var2->get_name() );
-                        newClass.allowWidening = widen1 && widen2;
-                        newClass.data = data;
-                        env.add( newClass );
-                } // if
-                delete type1;
-                delete type2;
-                return result;
-        }
-
         bool unify( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, OpenVarSet &openVars, const SymTab::Indexer &indexer ) {
                 OpenVarSet closedVars;
@@ -321 +173 @@
 
                 if ( isopen1 && isopen2 && entry1->second == entry2->second ) {
-                        result = bindVarToVar( var1, var2, entry1->second, env, needAssertions, haveAssertions, openVars, widenMode, indexer );
+                        result = env.bindVarToVar( var1, var2, entry1->second, needAssertions, haveAssertions, openVars, widenMode, indexer );
                 } else if ( isopen1 ) {
-                        result = bindVar( var1, type2, entry1->second, env, needAssertions, haveAssertions, openVars, widenMode, indexer );
+                        result = env.bindVar( var1, type2, entry1->second, needAssertions, haveAssertions, openVars, widenMode, indexer );
                 } else if ( isopen2 ) { // TODO: swap widenMode values in call, since type positions are flipped?
-                        result = bindVar( var2, type1, entry2->second, env, needAssertions, haveAssertions, openVars, widenMode, indexer );
+                        result = env.bindVar( var2, type1, entry2->second, needAssertions, haveAssertions, openVars, widenMode, indexer );
                 } else {
                         PassVisitor<Unify> comparator( type2, env, needAssertions, haveAssertions, openVars, widenMode, indexer );

src/ResolvExpr/Unify.h

@@ -9 +9 @@
 // Author           : Richard C. Bilson
 // Created On       : Sun May 17 13:09:04 2015
-// Last Modified By : Peter A. Buhr
-// Last Modified On : Fri Jul 21 23:09:34 2017
-// Update Count     : 3
+// Last Modified By : Aaron B. Moss
+// Last Modified On : Mon Jun 18 11:58:00 2018
+// Update Count     : 4
 //
 
@@ -21 +21 @@
 #include "SynTree/Declaration.h"  // for TypeDecl, TypeDecl::Data
 #include "TypeEnvironment.h"      // for AssertionSet, OpenVarSet
+#include "WidenMode.h"            // for WidenMode
 
 class Type;
@@ -29 +30 @@
 
 namespace ResolvExpr {
-        struct WidenMode {
-                WidenMode( bool widenFirst, bool widenSecond ): widenFirst( widenFirst ), widenSecond( widenSecond ) {}
-                WidenMode &operator|=( const WidenMode &other ) { widenFirst |= other.widenFirst; widenSecond |= other.widenSecond; return *this; }
-                WidenMode &operator&=( const WidenMode &other ) { widenFirst &= other.widenFirst; widenSecond &= other.widenSecond; return *this; }
-                WidenMode operator|( const WidenMode &other ) { WidenMode newWM( *this ); newWM |= other; return newWM; }
-                WidenMode operator&( const WidenMode &other ) { WidenMode newWM( *this ); newWM &= other; return newWM; }
-                operator bool() { return widenFirst && widenSecond; }
-
-                bool widenFirst : 1, widenSecond : 1;
-        };
-
-        bool bindVar( TypeInstType *typeInst, Type *other, const TypeDecl::Data & data, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer );
         bool unify( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, OpenVarSet &openVars, const SymTab::Indexer &indexer );
         bool unify( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, OpenVarSet &openVars, const SymTab::Indexer &indexer, Type *&commonType );
         bool unifyExact( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, OpenVarSet &openVars, const SymTab::Indexer &indexer );
+        bool unifyInexact( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer, Type *&common );
 
         template< typename Iterator1, typename Iterator2 >