Changeset b067d9b for src/SymTab/Validate.cc

Timestamp:

Oct 29, 2019, 4:01:24 PM (6 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

773db65, 9421f3d8

Parents:

7951100 (diff), 8364209 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge branch 'master' of plg.uwaterloo.ca:software/cfa/cfa-cc

File:

• src/SymTab/Validate.cc (modified) (48 diffs)

src/SymTab/Validate.cc

@@ -9 +9 @@
 // Author           : Richard C. Bilson
 // Created On       : Sun May 17 21:50:04 2015
-// Last Modified By : Peter A. Buhr
-// Last Modified On : Mon Aug 28 13:47:23 2017
-// Update Count     : 359
+// Last Modified By : Andrew Beach
+// Last Modified On : Wed Aug  7 6:42:00 2019
+// Update Count     : 360
 //
 
@@ -44 +44 @@
 #include <list>                        // for list
 #include <string>                      // for string
+#include <unordered_map>               // for unordered_map
 #include <utility>                     // for pair
 
+#include "AST/Chain.hpp"
+#include "AST/Decl.hpp"
+#include "AST/Node.hpp"
+#include "AST/Pass.hpp"
+#include "AST/SymbolTable.hpp"
+#include "AST/Type.hpp"
+#include "AST/TypeSubstitution.hpp"
 #include "CodeGen/CodeGenerator.h"     // for genName
 #include "CodeGen/OperatorTable.h"     // for isCtorDtor, isCtorDtorAssign
 #include "ControlStruct/Mutate.h"      // for ForExprMutator
+#include "Common/CodeLocation.h"       // for CodeLocation
+#include "Common/Stats.h"              // for Stats::Heap
 #include "Common/PassVisitor.h"        // for PassVisitor, WithDeclsToAdd
 #include "Common/ScopedMap.h"          // for ScopedMap
@@ -61 +71 @@
 #include "Parser/LinkageSpec.h"        // for C
 #include "ResolvExpr/typeops.h"        // for typesCompatible
+#include "ResolvExpr/Resolver.h"       // for findSingleExpression
+#include "ResolvExpr/ResolveTypeof.h"  // for resolveTypeof
 #include "SymTab/Autogen.h"            // for SizeType
 #include "SynTree/Attribute.h"         // for noAttributes, Attribute
@@ -72 +84 @@
 #include "SynTree/TypeSubstitution.h"  // for TypeSubstitution
 #include "SynTree/Visitor.h"           // for Visitor
+#include "Validate/HandleAttributes.h" // for handleAttributes
+#include "Validate/FindSpecialDecls.h" // for FindSpecialDecls
 
 class CompoundStmt;
@@ -77 +91 @@
 class SwitchStmt;
 
-#define debugPrint( x ) if ( doDebug ) { std::cout << x; }
+#define debugPrint( x ) if ( doDebug ) x
 
 namespace SymTab {
+        /// hoists declarations that are difficult to hoist while parsing
+        struct HoistTypeDecls final : public WithDeclsToAdd {
+                void previsit( SizeofExpr * );
+                void previsit( AlignofExpr * );
+                void previsit( UntypedOffsetofExpr * );
+                void previsit( CompoundLiteralExpr * );
+                void handleType( Type * );
+        };
+
+        struct FixQualifiedTypes final : public WithIndexer {
+                Type * postmutate( QualifiedType * );
+        };
+
         struct HoistStruct final : public WithDeclsToAdd, public WithGuards {
                 /// Flattens nested struct types
                 static void hoistStruct( std::list< Declaration * > &translationUnit );
 
-                void previsit( EnumInstType * enumInstType );
-                void previsit( StructInstType * structInstType );
-                void previsit( UnionInstType * unionInstType );
                 void previsit( StructDecl * aggregateDecl );
                 void previsit( UnionDecl * aggregateDecl );
                 void previsit( StaticAssertDecl * assertDecl );
+                void previsit( StructInstType * type );
+                void previsit( UnionInstType * type );
+                void previsit( EnumInstType * type );
 
           private:
-                template< typename AggDecl > void handleAggregate( AggDecl *aggregateDecl );
+                template< typename AggDecl > void handleAggregate( AggDecl * aggregateDecl );
 
                 AggregateDecl * parentAggr = nullptr;
@@ -106 +133 @@
 
         /// Replaces enum types by int, and function or array types in function parameter and return lists by appropriate pointers.
-        struct EnumAndPointerDecay {
-                void previsit( EnumDecl *aggregateDecl );
-                void previsit( FunctionType *func );
+        struct EnumAndPointerDecay_old {
+                void previsit( EnumDecl * aggregateDecl );
+                void previsit( FunctionType * func );
         };
 
         /// Associates forward declarations of aggregates with their definitions
-        struct LinkReferenceToTypes final : public WithIndexer, public WithGuards {
-                LinkReferenceToTypes( const Indexer *indexer );
-                void postvisit( TypeInstType *typeInst );
-
-                void postvisit( EnumInstType *enumInst );
-                void postvisit( StructInstType *structInst );
-                void postvisit( UnionInstType *unionInst );
-                void postvisit( TraitInstType *traitInst );
-
-                void postvisit( EnumDecl *enumDecl );
-                void postvisit( StructDecl *structDecl );
-                void postvisit( UnionDecl *unionDecl );
+        struct LinkReferenceToTypes_old final : public WithIndexer, public WithGuards, public WithVisitorRef<LinkReferenceToTypes_old>, public WithShortCircuiting {
+                LinkReferenceToTypes_old( const Indexer * indexer );
+                void postvisit( TypeInstType * typeInst );
+
+                void postvisit( EnumInstType * enumInst );
+                void postvisit( StructInstType * structInst );
+                void postvisit( UnionInstType * unionInst );
+                void postvisit( TraitInstType * traitInst );
+                void previsit( QualifiedType * qualType );
+                void postvisit( QualifiedType * qualType );
+
+                void postvisit( EnumDecl * enumDecl );
+                void postvisit( StructDecl * structDecl );
+                void postvisit( UnionDecl * unionDecl );
                 void postvisit( TraitDecl * traitDecl );
 
-                void previsit( StructDecl *structDecl );
-                void previsit( UnionDecl *unionDecl );
+                void previsit( StructDecl * structDecl );
+                void previsit( UnionDecl * unionDecl );
 
                 void renameGenericParams( std::list< TypeDecl * > & params );
 
           private:
-                const Indexer *local_indexer;
+                const Indexer * local_indexer;
 
                 typedef std::map< std::string, std::list< EnumInstType * > > ForwardEnumsType;
@@ -145 +174 @@
 
         /// Replaces array and function types in forall lists by appropriate pointer type and assigns each Object and Function declaration a unique ID.
-        struct ForallPointerDecay final {
+        struct ForallPointerDecay_old final {
                 void previsit( ObjectDecl * object );
                 void previsit( FunctionDecl * func );
@@ -165 +194 @@
         };
 
-        struct EliminateTypedef final : public WithVisitorRef<EliminateTypedef>, public WithGuards {
-                EliminateTypedef() : scopeLevel( 0 ) {}
+        struct ReplaceTypedef final : public WithVisitorRef<ReplaceTypedef>, public WithGuards, public WithShortCircuiting, public WithDeclsToAdd {
+                ReplaceTypedef() : scopeLevel( 0 ) {}
                 /// Replaces typedefs by forward declarations
-                static void eliminateTypedef( std::list< Declaration * > &translationUnit );
-
+                static void replaceTypedef( std::list< Declaration * > &translationUnit );
+
+                void premutate( QualifiedType * );
+                Type * postmutate( QualifiedType * qualType );
                 Type * postmutate( TypeInstType * aggregateUseType );
                 Declaration * postmutate( TypedefDecl * typeDecl );
@@ -180 +211 @@
 
                 void premutate( CompoundStmt * compoundStmt );
-                CompoundStmt * postmutate( CompoundStmt * compoundStmt );
 
                 void premutate( StructDecl * structDecl );
-                Declaration * postmutate( StructDecl * structDecl );
                 void premutate( UnionDecl * unionDecl );
-                Declaration * postmutate( UnionDecl * unionDecl );
                 void premutate( EnumDecl * enumDecl );
-                Declaration * postmutate( EnumDecl * enumDecl );
-                Declaration * postmutate( TraitDecl * contextDecl );
+                void premutate( TraitDecl * );
 
                 void premutate( FunctionType * ftype );
@@ -194 +221 @@
           private:
                 template<typename AggDecl>
-                AggDecl *handleAggregate( AggDecl * aggDecl );
-
-                template<typename AggDecl>
                 void addImplicitTypedef( AggDecl * aggDecl );
+                template< typename AggDecl >
+                void handleAggregate( AggDecl * aggr );
 
                 typedef std::unique_ptr<TypedefDecl> TypedefDeclPtr;
                 typedef ScopedMap< std::string, std::pair< TypedefDeclPtr, int > > TypedefMap;
-                typedef std::map< std::string, TypeDecl * > TypeDeclMap;
+                typedef ScopedMap< std::string, TypeDecl * > TypeDeclMap;
                 TypedefMap typedefNames;
                 TypeDeclMap typedeclNames;
                 int scopeLevel;
                 bool inFunctionType = false;
+        };
+
+        struct EliminateTypedef {
+                /// removes TypedefDecls from the AST
+                static void eliminateTypedef( std::list< Declaration * > &translationUnit );
+
+                template<typename AggDecl>
+                void handleAggregate( AggDecl * aggregateDecl );
+
+                void previsit( StructDecl * aggregateDecl );
+                void previsit( UnionDecl * aggregateDecl );
+                void previsit( CompoundStmt * compoundStmt );
         };
 
@@ -214 +252 @@
                 static void verify( std::list< Declaration * > &translationUnit );
 
-                void previsit( FunctionDecl *funcDecl );
+                void previsit( FunctionDecl * funcDecl );
         };
 
@@ -223 +261 @@
         };
 
-        struct ArrayLength {
+        struct FixObjectType : public WithIndexer {
+                /// resolves typeof type in object, function, and type declarations
+                static void fix( std::list< Declaration * > & translationUnit );
+
+                void previsit( ObjectDecl * );
+                void previsit( FunctionDecl * );
+                void previsit( TypeDecl * );
+        };
+
+        struct ArrayLength : public WithIndexer {
                 /// for array types without an explicit length, compute the length and store it so that it
                 /// is known to the rest of the phases. For example,
@@ -234 +281 @@
 
                 void previsit( ObjectDecl * objDecl );
+                void previsit( ArrayType * arrayType );
         };
 
@@ -239 +287 @@
                 Type::StorageClasses storageClasses;
 
-                void premutate( ObjectDecl *objectDecl );
-                Expression * postmutate( CompoundLiteralExpr *compLitExpr );
+                void premutate( ObjectDecl * objectDecl );
+                Expression * postmutate( CompoundLiteralExpr * compLitExpr );
         };
 
@@ -250 +298 @@
         };
 
-        FunctionDecl * dereferenceOperator = nullptr;
-        struct FindSpecialDeclarations final {
-                void previsit( FunctionDecl * funcDecl );
-        };
-
         void validate( std::list< Declaration * > &translationUnit, __attribute__((unused)) bool doDebug ) {
-                PassVisitor<EnumAndPointerDecay> epc;
-                PassVisitor<LinkReferenceToTypes> lrt( nullptr );
-                PassVisitor<ForallPointerDecay> fpd;
+                PassVisitor<EnumAndPointerDecay_old> epc;
+                PassVisitor<LinkReferenceToTypes_old> lrt( nullptr );
+                PassVisitor<ForallPointerDecay_old> fpd;
                 PassVisitor<CompoundLiteral> compoundliteral;
                 PassVisitor<ValidateGenericParameters> genericParams;
-                PassVisitor<FindSpecialDeclarations> finder;
                 PassVisitor<LabelAddressFixer> labelAddrFixer;
-
-                EliminateTypedef::eliminateTypedef( translationUnit );
-                HoistStruct::hoistStruct( translationUnit ); // must happen after EliminateTypedef, so that aggregate typedefs occur in the correct order
-                ReturnTypeFixer::fix( translationUnit ); // must happen before autogen
-                acceptAll( translationUnit, epc ); // must happen before VerifyCtorDtorAssign, because void return objects should not exist; before LinkReferenceToTypes because it is an indexer and needs correct types for mangling
-                acceptAll( translationUnit, lrt ); // must happen before autogen, because sized flag needs to propagate to generated functions
-                acceptAll( translationUnit, genericParams );  // check as early as possible - can't happen before LinkReferenceToTypes
-                VerifyCtorDtorAssign::verify( translationUnit );  // must happen before autogen, because autogen examines existing ctor/dtors
-                ReturnChecker::checkFunctionReturns( translationUnit );
-                InitTweak::fixReturnStatements( translationUnit ); // must happen before autogen
-                Concurrency::applyKeywords( translationUnit );
-                acceptAll( translationUnit, fpd ); // must happen before autogenerateRoutines, after Concurrency::applyKeywords because uniqueIds must be set on declaration before resolution
-                ControlStruct::hoistControlDecls( translationUnit );  // hoist initialization out of for statements; must happen before autogenerateRoutines
-                autogenerateRoutines( translationUnit ); // moved up, used to be below compoundLiteral - currently needs EnumAndPointerDecay
-                Concurrency::implementMutexFuncs( translationUnit );
-                Concurrency::implementThreadStarter( translationUnit );
-                mutateAll( translationUnit, compoundliteral );
-                ArrayLength::computeLength( translationUnit );
-                acceptAll( translationUnit, finder ); // xxx - remove this pass soon
-                mutateAll( translationUnit, labelAddrFixer );
-        }
-
-        void validateType( Type *type, const Indexer *indexer ) {
-                PassVisitor<EnumAndPointerDecay> epc;
-                PassVisitor<LinkReferenceToTypes> lrt( indexer );
-                PassVisitor<ForallPointerDecay> fpd;
+                PassVisitor<HoistTypeDecls> hoistDecls;
+                PassVisitor<FixQualifiedTypes> fixQual;
+
+                {
+                        Stats::Heap::newPass("validate-A");
+                        Stats::Time::BlockGuard guard("validate-A");
+                        acceptAll( translationUnit, hoistDecls );
+                        ReplaceTypedef::replaceTypedef( translationUnit );
+                        ReturnTypeFixer::fix( translationUnit ); // must happen before autogen
+                        acceptAll( translationUnit, epc ); // must happen before VerifyCtorDtorAssign, because void return objects should not exist; before LinkReferenceToTypes_old because it is an indexer and needs correct types for mangling
+                }
+                {
+                        Stats::Heap::newPass("validate-B");
+                        Stats::Time::BlockGuard guard("validate-B");
+                        Stats::Time::TimeBlock("Link Reference To Types", [&]() {
+                                acceptAll( translationUnit, lrt ); // must happen before autogen, because sized flag needs to propagate to generated functions
+                        });
+                        Stats::Time::TimeBlock("Fix Qualified Types", [&]() {
+                                mutateAll( translationUnit, fixQual ); // must happen after LinkReferenceToTypes_old, because aggregate members are accessed
+                        });
+                        Stats::Time::TimeBlock("Hoist Structs", [&]() {
+                                HoistStruct::hoistStruct( translationUnit ); // must happen after EliminateTypedef, so that aggregate typedefs occur in the correct order
+                        });
+                        Stats::Time::TimeBlock("Eliminate Typedefs", [&]() {
+                                EliminateTypedef::eliminateTypedef( translationUnit ); //
+                        });
+                }
+                {
+                        Stats::Heap::newPass("validate-C");
+                        Stats::Time::BlockGuard guard("validate-C");
+                        acceptAll( translationUnit, genericParams );  // check as early as possible - can't happen before LinkReferenceToTypes_old
+                        VerifyCtorDtorAssign::verify( translationUnit );  // must happen before autogen, because autogen examines existing ctor/dtors
+                        ReturnChecker::checkFunctionReturns( translationUnit );
+                        InitTweak::fixReturnStatements( translationUnit ); // must happen before autogen
+                }
+                {
+                        Stats::Heap::newPass("validate-D");
+                        Stats::Time::BlockGuard guard("validate-D");
+                        Stats::Time::TimeBlock("Apply Concurrent Keywords", [&]() {
+                                Concurrency::applyKeywords( translationUnit );
+                        });
+                        Stats::Time::TimeBlock("Forall Pointer Decay", [&]() {
+                                acceptAll( translationUnit, fpd ); // must happen before autogenerateRoutines, after Concurrency::applyKeywords because uniqueIds must be set on declaration before resolution
+                        });
+                        Stats::Time::TimeBlock("Hoist Control Declarations", [&]() {
+                                ControlStruct::hoistControlDecls( translationUnit );  // hoist initialization out of for statements; must happen before autogenerateRoutines
+                        });
+                        Stats::Time::TimeBlock("Generate Autogen routines", [&]() {
+                                autogenerateRoutines( translationUnit ); // moved up, used to be below compoundLiteral - currently needs EnumAndPointerDecay_old
+                        });
+                }
+                {
+                        Stats::Heap::newPass("validate-E");
+                        Stats::Time::BlockGuard guard("validate-E");
+                        Stats::Time::TimeBlock("Implement Mutex Func", [&]() {
+                                Concurrency::implementMutexFuncs( translationUnit );
+                        });
+                        Stats::Time::TimeBlock("Implement Thread Start", [&]() {
+                                Concurrency::implementThreadStarter( translationUnit );
+                        });
+                        Stats::Time::TimeBlock("Compound Literal", [&]() {
+                                mutateAll( translationUnit, compoundliteral );
+                        });
+                        Stats::Time::TimeBlock("Resolve With Expressions", [&]() {
+                                ResolvExpr::resolveWithExprs( translationUnit ); // must happen before FixObjectType because user-code is resolved and may contain with variables
+                        });
+                }
+                {
+                        Stats::Heap::newPass("validate-F");
+                        Stats::Time::BlockGuard guard("validate-F");
+                        Stats::Time::TimeBlock("Fix Object Type", [&]() {
+                                FixObjectType::fix( translationUnit );
+                        });
+                        Stats::Time::TimeBlock("Array Length", [&]() {
+                                ArrayLength::computeLength( translationUnit );
+                        });
+                        Stats::Time::TimeBlock("Find Special Declarations", [&]() {
+                                Validate::findSpecialDecls( translationUnit );
+                        });
+                        Stats::Time::TimeBlock("Fix Label Address", [&]() {
+                                mutateAll( translationUnit, labelAddrFixer );
+                        });
+                        Stats::Time::TimeBlock("Handle Attributes", [&]() {
+                                Validate::handleAttributes( translationUnit );
+                        });
+                }
+        }
+
+        void validateType( Type * type, const Indexer * indexer ) {
+                PassVisitor<EnumAndPointerDecay_old> epc;
+                PassVisitor<LinkReferenceToTypes_old> lrt( indexer );
+                PassVisitor<ForallPointerDecay_old> fpd;
                 type->accept( epc );
                 type->accept( lrt );
@@ -294 +402 @@
         }
 
+
+        void HoistTypeDecls::handleType( Type * type ) {
+                // some type declarations are buried in expressions and not easy to hoist during parsing; hoist them here
+                AggregateDecl * aggr = nullptr;
+                if ( StructInstType * inst = dynamic_cast< StructInstType * >( type ) ) {
+                        aggr = inst->baseStruct;
+                } else if ( UnionInstType * inst = dynamic_cast< UnionInstType * >( type ) ) {
+                        aggr = inst->baseUnion;
+                } else if ( EnumInstType * inst = dynamic_cast< EnumInstType * >( type ) ) {
+                        aggr = inst->baseEnum;
+                }
+                if ( aggr && aggr->body ) {
+                        declsToAddBefore.push_front( aggr );
+                }
+        }
+
+        void HoistTypeDecls::previsit( SizeofExpr * expr ) {
+                handleType( expr->type );
+        }
+
+        void HoistTypeDecls::previsit( AlignofExpr * expr ) {
+                handleType( expr->type );
+        }
+
+        void HoistTypeDecls::previsit( UntypedOffsetofExpr * expr ) {
+                handleType( expr->type );
+        }
+
+        void HoistTypeDecls::previsit( CompoundLiteralExpr * expr ) {
+                handleType( expr->result );
+        }
+
+
+        Type * FixQualifiedTypes::postmutate( QualifiedType * qualType ) {
+                Type * parent = qualType->parent;
+                Type * child = qualType->child;
+                if ( dynamic_cast< GlobalScopeType * >( qualType->parent ) ) {
+                        // .T => lookup T at global scope
+                        if ( TypeInstType * inst = dynamic_cast< TypeInstType * >( child ) ) {
+                                auto td = indexer.globalLookupType( inst->name );
+                                if ( ! td ) {
+                                        SemanticError( qualType->location, toString("Use of undefined global type ", inst->name) );
+                                }
+                                auto base = td->base;
+                                assert( base );
+                                Type * ret = base->clone();
+                                ret->get_qualifiers() = qualType->get_qualifiers();
+                                return ret;
+                        } else {
+                                // .T => T is not a type name
+                                assertf( false, "unhandled global qualified child type: %s", toCString(child) );
+                        }
+                } else {
+                        // S.T => S must be an aggregate type, find the declaration for T in S.
+                        AggregateDecl * aggr = nullptr;
+                        if ( StructInstType * inst = dynamic_cast< StructInstType * >( parent ) ) {
+                                aggr = inst->baseStruct;
+                        } else if ( UnionInstType * inst = dynamic_cast< UnionInstType * > ( parent ) ) {
+                                aggr = inst->baseUnion;
+                        } else {
+                                SemanticError( qualType->location, toString("Qualified type requires an aggregate on the left, but has: ", parent) );
+                        }
+                        assert( aggr ); // TODO: need to handle forward declarations
+                        for ( Declaration * member : aggr->members ) {
+                                if ( TypeInstType * inst = dynamic_cast< TypeInstType * >( child ) ) {
+                                        // name on the right is a typedef
+                                        if ( NamedTypeDecl * aggr = dynamic_cast< NamedTypeDecl * > ( member ) ) {
+                                                if ( aggr->name == inst->name ) {
+                                                        assert( aggr->base );
+                                                        Type * ret = aggr->base->clone();
+                                                        ret->get_qualifiers() = qualType->get_qualifiers();
+                                                        TypeSubstitution sub = parent->genericSubstitution();
+                                                        sub.apply(ret);
+                                                        return ret;
+                                                }
+                                        }
+                                } else {
+                                        // S.T - S is not an aggregate => error
+                                        assertf( false, "unhandled qualified child type: %s", toCString(qualType) );
+                                }
+                        }
+                        // failed to find a satisfying definition of type
+                        SemanticError( qualType->location, toString("Undefined type in qualified type: ", qualType) );
+                }
+
+                // ... may want to link canonical SUE definition to each forward decl so that it becomes easier to lookup?
+        }
+
+
         void HoistStruct::hoistStruct( std::list< Declaration * > &translationUnit ) {
                 PassVisitor<HoistStruct> hoister;
@@ -299 +496 @@
         }
 
-        bool shouldHoist( Declaration *decl ) {
+        bool shouldHoist( Declaration * decl ) {
                 return dynamic_cast< StructDecl * >( decl ) || dynamic_cast< UnionDecl * >( decl ) || dynamic_cast< StaticAssertDecl * >( decl );
         }
 
+        namespace {
+                void qualifiedName( AggregateDecl * aggr, std::ostringstream & ss ) {
+                        if ( aggr->parent ) qualifiedName( aggr->parent, ss );
+                        ss << "__" << aggr->name;
+                }
+
+                // mangle nested type names using entire parent chain
+                std::string qualifiedName( AggregateDecl * aggr ) {
+                        std::ostringstream ss;
+                        qualifiedName( aggr, ss );
+                        return ss.str();
+                }
+        }
+
         template< typename AggDecl >
-        void HoistStruct::handleAggregate( AggDecl *aggregateDecl ) {
+        void HoistStruct::handleAggregate( AggDecl * aggregateDecl ) {
                 if ( parentAggr ) {
+                        aggregateDecl->parent = parentAggr;
+                        aggregateDecl->name = qualifiedName( aggregateDecl );
                         // Add elements in stack order corresponding to nesting structure.
                         declsToAddBefore.push_front( aggregateDecl );
@@ -316 +529 @@
         }
 
-        void HoistStruct::previsit( EnumInstType * inst ) {
-                if ( inst->baseEnum && inst->baseEnum->body ) {
-                        declsToAddBefore.push_front( inst->baseEnum );
-                }
-        }
-
-        void HoistStruct::previsit( StructInstType * inst ) {
-                if ( inst->baseStruct && inst->baseStruct->body ) {
-                        declsToAddBefore.push_front( inst->baseStruct );
-                }
-        }
-
-        void HoistStruct::previsit( UnionInstType * inst ) {
-                if ( inst->baseUnion && inst->baseUnion->body ) {
-                        declsToAddBefore.push_front( inst->baseUnion );
-                }
-        }
-
         void HoistStruct::previsit( StaticAssertDecl * assertDecl ) {
                 if ( parentAggr ) {
@@ -348 +543 @@
         }
 
-        void EnumAndPointerDecay::previsit( EnumDecl *enumDecl ) {
+        void HoistStruct::previsit( StructInstType * type ) {
+                // need to reset type name after expanding to qualified name
+                assert( type->baseStruct );
+                type->name = type->baseStruct->name;
+        }
+
+        void HoistStruct::previsit( UnionInstType * type ) {
+                assert( type->baseUnion );
+                type->name = type->baseUnion->name;
+        }
+
+        void HoistStruct::previsit( EnumInstType * type ) {
+                assert( type->baseEnum );
+                type->name = type->baseEnum->name;
+        }
+
+
+        bool isTypedef( Declaration * decl ) {
+                return dynamic_cast< TypedefDecl * >( decl );
+        }
+
+        void EliminateTypedef::eliminateTypedef( std::list< Declaration * > &translationUnit ) {
+                PassVisitor<EliminateTypedef> eliminator;
+                acceptAll( translationUnit, eliminator );
+                filter( translationUnit, isTypedef, true );
+        }
+
+        template< typename AggDecl >
+        void EliminateTypedef::handleAggregate( AggDecl * aggregateDecl ) {
+                filter( aggregateDecl->members, isTypedef, true );
+        }
+
+        void EliminateTypedef::previsit( StructDecl * aggregateDecl ) {
+                handleAggregate( aggregateDecl );
+        }
+
+        void EliminateTypedef::previsit( UnionDecl * aggregateDecl ) {
+                handleAggregate( aggregateDecl );
+        }
+
+        void EliminateTypedef::previsit( CompoundStmt * compoundStmt ) {
+                // remove and delete decl stmts
+                filter( compoundStmt->kids, [](Statement * stmt) {
+                        if ( DeclStmt * declStmt = dynamic_cast< DeclStmt * >( stmt ) ) {
+                                if ( dynamic_cast< TypedefDecl * >( declStmt->decl ) ) {
+                                        return true;
+                                } // if
+                        } // if
+                        return false;
+                }, true);
+        }
+
+        void EnumAndPointerDecay_old::previsit( EnumDecl * enumDecl ) {
                 // Set the type of each member of the enumeration to be EnumConstant
-                for ( std::list< Declaration * >::iterator i = enumDecl->get_members().begin(); i != enumDecl->get_members().end(); ++i ) {
-                        ObjectDecl * obj = dynamic_cast< ObjectDecl * >( *i );
+                for ( std::list< Declaration * >::iterator i = enumDecl->members.begin(); i != enumDecl->members.end(); ++i ) {
+                        ObjectDecl * obj = dynamic_cast< ObjectDecl * >( * i );
                         assert( obj );
-                        obj->set_type( new EnumInstType( Type::Qualifiers( Type::Const ), enumDecl->get_name() ) );
+                        obj->set_type( new EnumInstType( Type::Qualifiers( Type::Const ), enumDecl->name ) );
                 } // for
         }
@@ -380 +627 @@
         }
 
-        void EnumAndPointerDecay::previsit( FunctionType *func ) {
+        void EnumAndPointerDecay_old::previsit( FunctionType * func ) {
                 // Fix up parameters and return types
                 fixFunctionList( func->parameters, func->isVarArgs, func );
@@ -386 +633 @@
         }
 
-        LinkReferenceToTypes::LinkReferenceToTypes( const Indexer *other_indexer ) {
+        LinkReferenceToTypes_old::LinkReferenceToTypes_old( const Indexer * other_indexer ) {
                 if ( other_indexer ) {
                         local_indexer = other_indexer;
@@ -394 +641 @@
         }
 
-        void LinkReferenceToTypes::postvisit( EnumInstType *enumInst ) {
-                EnumDecl *st = local_indexer->lookupEnum( enumInst->get_name() );
+        void LinkReferenceToTypes_old::postvisit( EnumInstType * enumInst ) {
+                const EnumDecl * st = local_indexer->lookupEnum( enumInst->name );
                 // it's not a semantic error if the enum is not found, just an implicit forward declaration
                 if ( st ) {
-                        //assert( ! enumInst->get_baseEnum() || enumInst->get_baseEnum()->get_members().empty() || ! st->get_members().empty() );
-                        enumInst->set_baseEnum( st );
-                } // if
-                if ( ! st || st->get_members().empty() ) {
+                        enumInst->baseEnum = const_cast<EnumDecl *>(st); // Just linking in the node
+                } // if
+                if ( ! st || ! st->body ) {
                         // use of forward declaration
-                        forwardEnums[ enumInst->get_name() ].push_back( enumInst );
+                        forwardEnums[ enumInst->name ].push_back( enumInst );
                 } // if
         }
@@ -415 +661 @@
         }
 
-        void LinkReferenceToTypes::postvisit( StructInstType *structInst ) {
-                StructDecl *st = local_indexer->lookupStruct( structInst->get_name() );
+        void LinkReferenceToTypes_old::postvisit( StructInstType * structInst ) {
+                const StructDecl * st = local_indexer->lookupStruct( structInst->name );
                 // it's not a semantic error if the struct is not found, just an implicit forward declaration
                 if ( st ) {
-                        //assert( ! structInst->get_baseStruct() || structInst->get_baseStruct()->get_members().empty() || ! st->get_members().empty() );
-                        structInst->set_baseStruct( st );
-                } // if
-                if ( ! st || st->get_members().empty() ) {
+                        structInst->baseStruct = const_cast<StructDecl *>(st); // Just linking in the node
+                } // if
+                if ( ! st || ! st->body ) {
                         // use of forward declaration
-                        forwardStructs[ structInst->get_name() ].push_back( structInst );
+                        forwardStructs[ structInst->name ].push_back( structInst );
                 } // if
                 checkGenericParameters( structInst );
         }
 
-        void LinkReferenceToTypes::postvisit( UnionInstType *unionInst ) {
-                UnionDecl *un = local_indexer->lookupUnion( unionInst->get_name() );
+        void LinkReferenceToTypes_old::postvisit( UnionInstType * unionInst ) {
+                const UnionDecl * un = local_indexer->lookupUnion( unionInst->name );
                 // it's not a semantic error if the union is not found, just an implicit forward declaration
                 if ( un ) {
-                        unionInst->set_baseUnion( un );
-                } // if
-                if ( ! un || un->get_members().empty() ) {
+                        unionInst->baseUnion = const_cast<UnionDecl *>(un); // Just linking in the node
+                } // if
+                if ( ! un || ! un->body ) {
                         // use of forward declaration
-                        forwardUnions[ unionInst->get_name() ].push_back( unionInst );
+                        forwardUnions[ unionInst->name ].push_back( unionInst );
                 } // if
                 checkGenericParameters( unionInst );
+        }
+
+        void LinkReferenceToTypes_old::previsit( QualifiedType * ) {
+                visit_children = false;
+        }
+
+        void LinkReferenceToTypes_old::postvisit( QualifiedType * qualType ) {
+                // linking only makes sense for the 'oldest ancestor' of the qualified type
+                qualType->parent->accept( * visitor );
         }
 
@@ -450 +704 @@
                         DeclarationWithType * dwt2 = dynamic_cast<DeclarationWithType *>( d2 );
                         if ( dwt1 && dwt2 ) {
-                                if ( dwt1->get_name() == dwt2->get_name() && ResolvExpr::typesCompatible( dwt1->get_type(), dwt2->get_type(), SymTab::Indexer() ) ) {
+                                if ( dwt1->name == dwt2->name && ResolvExpr::typesCompatible( dwt1->get_type(), dwt2->get_type(), SymTab::Indexer() ) ) {
                                         // std::cerr << "=========== equal:" << std::endl;
                                         // std::cerr << "d1: " << d1 << std::endl;
@@ -475 +729 @@
         template< typename Iterator >
         void expandAssertions( TraitInstType * inst, Iterator out ) {
-                assertf( inst->baseTrait, "Trait instance not linked to base trait: %s", toString( inst ).c_str() );
+                assertf( inst->baseTrait, "Trait instance not linked to base trait: %s", toCString( inst ) );
                 std::list< DeclarationWithType * > asserts;
                 for ( Declaration * decl : inst->baseTrait->members ) {
@@ -484 +738 @@
         }
 
-        void LinkReferenceToTypes::postvisit( TraitDecl * traitDecl ) {
+        void LinkReferenceToTypes_old::postvisit( TraitDecl * traitDecl ) {
                 if ( traitDecl->name == "sized" ) {
                         // "sized" is a special trait - flick the sized status on for the type variable
@@ -506 +760 @@
         }
 
-        void LinkReferenceToTypes::postvisit( TraitInstType * traitInst ) {
+        void LinkReferenceToTypes_old::postvisit( TraitInstType * traitInst ) {
                 // handle other traits
-                TraitDecl *traitDecl = local_indexer->lookupTrait( traitInst->name );
+                const TraitDecl * traitDecl = local_indexer->lookupTrait( traitInst->name );
                 if ( ! traitDecl ) {
                         SemanticError( traitInst->location, "use of undeclared trait " + traitInst->name );
                 } // if
-                if ( traitDecl->get_parameters().size() != traitInst->get_parameters().size() ) {
+                if ( traitDecl->parameters.size() != traitInst->parameters.size() ) {
                         SemanticError( traitInst, "incorrect number of trait parameters: " );
                 } // if
-                traitInst->baseTrait = traitDecl;
+                traitInst->baseTrait = const_cast<TraitDecl *>(traitDecl); // Just linking in the node
 
                 // need to carry over the 'sized' status of each decl in the instance
-                for ( auto p : group_iterate( traitDecl->get_parameters(), traitInst->get_parameters() ) ) {
+                for ( auto p : group_iterate( traitDecl->parameters, traitInst->parameters ) ) {
                         TypeExpr * expr = dynamic_cast< TypeExpr * >( std::get<1>(p) );
                         if ( ! expr ) {
@@ -525 +779 @@
                         if ( TypeInstType * inst = dynamic_cast< TypeInstType * >( expr->get_type() ) ) {
                                 TypeDecl * formalDecl = std::get<0>(p);
-                                TypeDecl * instDecl = inst->get_baseType();
+                                TypeDecl * instDecl = inst->baseType;
                                 if ( formalDecl->get_sized() ) instDecl->set_sized( true );
                         }
@@ -532 +786 @@
         }
 
-        void LinkReferenceToTypes::postvisit( EnumDecl *enumDecl ) {
+        void LinkReferenceToTypes_old::postvisit( EnumDecl * enumDecl ) {
                 // visit enum members first so that the types of self-referencing members are updated properly
-                if ( ! enumDecl->get_members().empty() ) {
-                        ForwardEnumsType::iterator fwds = forwardEnums.find( enumDecl->get_name() );
+                if ( enumDecl->body ) {
+                        ForwardEnumsType::iterator fwds = forwardEnums.find( enumDecl->name );
                         if ( fwds != forwardEnums.end() ) {
                                 for ( std::list< EnumInstType * >::iterator inst = fwds->second.begin(); inst != fwds->second.end(); ++inst ) {
-                                        (*inst )->set_baseEnum( enumDecl );
+                                        (* inst)->baseEnum = enumDecl;
                                 } // for
                                 forwardEnums.erase( fwds );
                         } // if
-                } // if
-        }
-
-        void LinkReferenceToTypes::renameGenericParams( std::list< TypeDecl * > & params ) {
+
+                        for ( Declaration * member : enumDecl->members ) {
+                                ObjectDecl * field = strict_dynamic_cast<ObjectDecl *>( member );
+                                if ( field->init ) {
+                                        // need to resolve enumerator initializers early so that other passes that determine if an expression is constexpr have the appropriate information.
+                                        SingleInit * init = strict_dynamic_cast<SingleInit *>( field->init );
+                                        ResolvExpr::findSingleExpression( init->value, new BasicType( Type::Qualifiers(), BasicType::SignedInt ), indexer );
+                                }
+                        }
+                } // if
+        }
+
+        void LinkReferenceToTypes_old::renameGenericParams( std::list< TypeDecl * > & params ) {
                 // rename generic type parameters uniquely so that they do not conflict with user-defined function forall parameters, e.g.
                 //   forall(otype T)
@@ -563 +826 @@
         }
 
-        void LinkReferenceToTypes::previsit( StructDecl * structDecl ) {
+        void LinkReferenceToTypes_old::previsit( StructDecl * structDecl ) {
                 renameGenericParams( structDecl->parameters );
         }
 
-        void LinkReferenceToTypes::previsit( UnionDecl * unionDecl ) {
+        void LinkReferenceToTypes_old::previsit( UnionDecl * unionDecl ) {
                 renameGenericParams( unionDecl->parameters );
         }
 
-        void LinkReferenceToTypes::postvisit( StructDecl *structDecl ) {
+        void LinkReferenceToTypes_old::postvisit( StructDecl * structDecl ) {
                 // visit struct members first so that the types of self-referencing members are updated properly
                 // xxx - need to ensure that type parameters match up between forward declarations and definition (most importantly, number of type parameters and their defaults)
-                if ( ! structDecl->get_members().empty() ) {
-                        ForwardStructsType::iterator fwds = forwardStructs.find( structDecl->get_name() );
+                if ( structDecl->body ) {
+                        ForwardStructsType::iterator fwds = forwardStructs.find( structDecl->name );
                         if ( fwds != forwardStructs.end() ) {
                                 for ( std::list< StructInstType * >::iterator inst = fwds->second.begin(); inst != fwds->second.end(); ++inst ) {
-                                        (*inst )->set_baseStruct( structDecl );
+                                        (* inst)->baseStruct = structDecl;
                                 } // for
                                 forwardStructs.erase( fwds );
@@ -585 +848 @@
         }
 
-        void LinkReferenceToTypes::postvisit( UnionDecl *unionDecl ) {
-                if ( ! unionDecl->get_members().empty() ) {
-                        ForwardUnionsType::iterator fwds = forwardUnions.find( unionDecl->get_name() );
+        void LinkReferenceToTypes_old::postvisit( UnionDecl * unionDecl ) {
+                if ( unionDecl->body ) {
+                        ForwardUnionsType::iterator fwds = forwardUnions.find( unionDecl->name );
                         if ( fwds != forwardUnions.end() ) {
                                 for ( std::list< UnionInstType * >::iterator inst = fwds->second.begin(); inst != fwds->second.end(); ++inst ) {
-                                        (*inst )->set_baseUnion( unionDecl );
+                                        (* inst)->baseUnion = unionDecl;
                                 } // for
                                 forwardUnions.erase( fwds );
@@ -597 +860 @@
         }
 
-        void LinkReferenceToTypes::postvisit( TypeInstType *typeInst ) {
+        void LinkReferenceToTypes_old::postvisit( TypeInstType * typeInst ) {
                 // ensure generic parameter instances are renamed like the base type
                 if ( inGeneric && typeInst->baseType ) typeInst->name = typeInst->baseType->name;
-                if ( NamedTypeDecl *namedTypeDecl = local_indexer->lookupType( typeInst->get_name() ) ) {
-                        if ( TypeDecl *typeDecl = dynamic_cast< TypeDecl * >( namedTypeDecl ) ) {
-                                typeInst->set_isFtype( typeDecl->get_kind() == TypeDecl::Ftype );
+                if ( const NamedTypeDecl * namedTypeDecl = local_indexer->lookupType( typeInst->name ) ) {
+                        if ( const TypeDecl * typeDecl = dynamic_cast< const TypeDecl * >( namedTypeDecl ) ) {
+                                typeInst->set_isFtype( typeDecl->kind == TypeDecl::Ftype );
                         } // if
                 } // if
@@ -614 +877 @@
                         // expand trait instances into their members
                         for ( DeclarationWithType * assertion : asserts ) {
-                                if ( TraitInstType *traitInst = dynamic_cast< TraitInstType * >( assertion->get_type() ) ) {
+                                if ( TraitInstType * traitInst = dynamic_cast< TraitInstType * >( assertion->get_type() ) ) {
                                         // expand trait instance into all of its members
                                         expandAssertions( traitInst, back_inserter( type->assertions ) );
@@ -634 +897 @@
         }
 
-        void ForallPointerDecay::previsit( ObjectDecl *object ) {
+        void ForallPointerDecay_old::previsit( ObjectDecl * object ) {
                 // ensure that operator names only apply to functions or function pointers
                 if ( CodeGen::isOperator( object->name ) && ! dynamic_cast< FunctionType * >( object->type->stripDeclarator() ) ) {
@@ -642 +905 @@
         }
 
-        void ForallPointerDecay::previsit( FunctionDecl *func ) {
+        void ForallPointerDecay_old::previsit( FunctionDecl * func ) {
                 func->fixUniqueId();
         }
 
-        void ForallPointerDecay::previsit( FunctionType * ftype ) {
+        void ForallPointerDecay_old::previsit( FunctionType * ftype ) {
                 forallFixer( ftype->forall, ftype );
         }
 
-        void ForallPointerDecay::previsit( StructDecl * aggrDecl ) {
+        void ForallPointerDecay_old::previsit( StructDecl * aggrDecl ) {
                 forallFixer( aggrDecl->parameters, aggrDecl );
         }
 
-        void ForallPointerDecay::previsit( UnionDecl * aggrDecl ) {
+        void ForallPointerDecay_old::previsit( UnionDecl * aggrDecl ) {
                 forallFixer( aggrDecl->parameters, aggrDecl );
         }
@@ -679 +942 @@
 
 
-        bool isTypedef( Declaration *decl ) {
-                return dynamic_cast< TypedefDecl * >( decl );
-        }
-
-        void EliminateTypedef::eliminateTypedef( std::list< Declaration * > &translationUnit ) {
-                PassVisitor<EliminateTypedef> eliminator;
+        void ReplaceTypedef::replaceTypedef( std::list< Declaration * > &translationUnit ) {
+                PassVisitor<ReplaceTypedef> eliminator;
                 mutateAll( translationUnit, eliminator );
                 if ( eliminator.pass.typedefNames.count( "size_t" ) ) {
                         // grab and remember declaration of size_t
-                        SizeType = eliminator.pass.typedefNames["size_t"].first->get_base()->clone();
+                        Validate::SizeType = eliminator.pass.typedefNames["size_t"].first->base->clone();
                 } else {
                         // xxx - missing global typedef for size_t - default to long unsigned int, even though that may be wrong
                         // eventually should have a warning for this case.
-                        SizeType = new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt );
-                }
-                filter( translationUnit, isTypedef, true );
-        }
-
-        Type * EliminateTypedef::postmutate( TypeInstType * typeInst ) {
+                        Validate::SizeType = new BasicType( Type::Qualifiers(), BasicType::LongUnsignedInt );
+                }
+        }
+
+        void ReplaceTypedef::premutate( QualifiedType * ) {
+                visit_children = false;
+        }
+
+        Type * ReplaceTypedef::postmutate( QualifiedType * qualType ) {
+                // replacing typedefs only makes sense for the 'oldest ancestor' of the qualified type
+                qualType->parent = qualType->parent->acceptMutator( * visitor );
+                return qualType;
+        }
+
+        Type * ReplaceTypedef::postmutate( TypeInstType * typeInst ) {
                 // instances of typedef types will come here. If it is an instance
                 // of a typdef type, link the instance to its actual type.
-                TypedefMap::const_iterator def = typedefNames.find( typeInst->get_name() );
+                TypedefMap::const_iterator def = typedefNames.find( typeInst->name );
                 if ( def != typedefNames.end() ) {
-                        Type *ret = def->second.first->base->clone();
+                        Type * ret = def->second.first->base->clone();
+                        ret->location = typeInst->location;
                         ret->get_qualifiers() |= typeInst->get_qualifiers();
                         // attributes are not carried over from typedef to function parameters/return values
@@ -713 +982 @@
                         // place instance parameters on the typedef'd type
                         if ( ! typeInst->parameters.empty() ) {
-                                ReferenceToType *rtt = dynamic_cast<ReferenceToType*>(ret);
+                                ReferenceToType * rtt = dynamic_cast<ReferenceToType *>(ret);
                                 if ( ! rtt ) {
                                         SemanticError( typeInst->location, "Cannot apply type parameters to base type of " + typeInst->name );
                                 }
-                                rtt->get_parameters().clear();
+                                rtt->parameters.clear();
                                 cloneAll( typeInst->parameters, rtt->parameters );
-                                mutateAll( rtt->parameters, *visitor );  // recursively fix typedefs on parameters
+                                mutateAll( rtt->parameters, * visitor );  // recursively fix typedefs on parameters
                         } // if
                         delete typeInst;
                         return ret;
                 } else {
-                        TypeDeclMap::const_iterator base = typedeclNames.find( typeInst->get_name() );
-                        assertf( base != typedeclNames.end(), "Cannot find typedecl name %s", typeInst->name.c_str() );
+                        TypeDeclMap::const_iterator base = typedeclNames.find( typeInst->name );
+                        if ( base == typedeclNames.end() ) {
+                                SemanticError( typeInst->location, toString("Use of undefined type ", typeInst->name) );
+                        }
                         typeInst->set_baseType( base->second );
-                } // if
-                return typeInst;
+                        return typeInst;
+                } // if
+                assert( false );
         }
 
@@ -745 +1017 @@
         }
 
-        Declaration *EliminateTypedef::postmutate( TypedefDecl * tyDecl ) {
-                if ( typedefNames.count( tyDecl->get_name() ) == 1 && typedefNames[ tyDecl->get_name() ].second == scopeLevel ) {
+        Declaration * ReplaceTypedef::postmutate( TypedefDecl * tyDecl ) {
+                if ( typedefNames.count( tyDecl->name ) == 1 && typedefNames[ tyDecl->name ].second == scopeLevel ) {
                         // typedef to the same name from the same scope
                         // must be from the same type
 
-                        Type * t1 = tyDecl->get_base();
-                        Type * t2 = typedefNames[ tyDecl->get_name() ].first->get_base();
+                        Type * t1 = tyDecl->base;
+                        Type * t2 = typedefNames[ tyDecl->name ].first->base;
                         if ( ! ResolvExpr::typesCompatible( t1, t2, Indexer() ) ) {
                                 SemanticError( tyDecl->location, "Cannot redefine typedef: " + tyDecl->name );
@@ -763 +1035 @@
                         }
                 } else {
-                        typedefNames[ tyDecl->get_name() ] = std::make_pair( TypedefDeclPtr( tyDecl ), scopeLevel );
+                        typedefNames[ tyDecl->name ] = std::make_pair( TypedefDeclPtr( tyDecl ), scopeLevel );
                 } // if
 
@@ -771 +1043 @@
                 //    struct screen;
                 // because the expansion of the typedef is:
-                //    void rtn( SCREEN *p ) => void rtn( struct screen *p )
+                //    void rtn( SCREEN * p ) => void rtn( struct screen * p )
                 // hence the type-name "screen" must be defined.
                 // Note, qualifiers on the typedef are superfluous for the forward declaration.
 
-                Type *designatorType = tyDecl->get_base()->stripDeclarator();
-                if ( StructInstType *aggDecl = dynamic_cast< StructInstType * >( designatorType ) ) {
-                        return new StructDecl( aggDecl->get_name(), DeclarationNode::Struct, noAttributes, tyDecl->get_linkage() );
-                } else if ( UnionInstType *aggDecl = dynamic_cast< UnionInstType * >( designatorType ) ) {
-                        return new UnionDecl( aggDecl->get_name(), noAttributes, tyDecl->get_linkage() );
-                } else if ( EnumInstType *enumDecl = dynamic_cast< EnumInstType * >( designatorType ) ) {
-                        return new EnumDecl( enumDecl->get_name(), noAttributes, tyDecl->get_linkage() );
-                } else {
-                        return tyDecl->clone();
-                } // if
-        }
-
-        void EliminateTypedef::premutate( TypeDecl * typeDecl ) {
-                TypedefMap::iterator i = typedefNames.find( typeDecl->get_name() );
+                Type * designatorType = tyDecl->base->stripDeclarator();
+                if ( StructInstType * aggDecl = dynamic_cast< StructInstType * >( designatorType ) ) {
+                        declsToAddBefore.push_back( new StructDecl( aggDecl->name, DeclarationNode::Struct, noAttributes, tyDecl->linkage ) );
+                } else if ( UnionInstType * aggDecl = dynamic_cast< UnionInstType * >( designatorType ) ) {
+                        declsToAddBefore.push_back( new UnionDecl( aggDecl->name, noAttributes, tyDecl->linkage ) );
+                } else if ( EnumInstType * enumDecl = dynamic_cast< EnumInstType * >( designatorType ) ) {
+                        declsToAddBefore.push_back( new EnumDecl( enumDecl->name, noAttributes, tyDecl->linkage ) );
+                } // if
+                return tyDecl->clone();
+        }
+
+        void ReplaceTypedef::premutate( TypeDecl * typeDecl ) {
+                TypedefMap::iterator i = typedefNames.find( typeDecl->name );
                 if ( i != typedefNames.end() ) {
                         typedefNames.erase( i ) ;
                 } // if
 
-                typedeclNames[ typeDecl->get_name() ] = typeDecl;
-        }
-
-        void EliminateTypedef::premutate( FunctionDecl * ) {
+                typedeclNames.insert( typeDecl->name, typeDecl );
+        }
+
+        void ReplaceTypedef::premutate( FunctionDecl * ) {
                 GuardScope( typedefNames );
-        }
-
-        void EliminateTypedef::premutate( ObjectDecl * ) {
+                GuardScope( typedeclNames );
+        }
+
+        void ReplaceTypedef::premutate( ObjectDecl * ) {
                 GuardScope( typedefNames );
-        }
-
-        DeclarationWithType *EliminateTypedef::postmutate( ObjectDecl * objDecl ) {
-                if ( FunctionType *funtype = dynamic_cast<FunctionType *>( objDecl->get_type() ) ) { // function type?
+                GuardScope( typedeclNames );
+        }
+
+        DeclarationWithType * ReplaceTypedef::postmutate( ObjectDecl * objDecl ) {
+                if ( FunctionType * funtype = dynamic_cast<FunctionType *>( objDecl->type ) ) { // function type?
                         // replace the current object declaration with a function declaration
-                        FunctionDecl * newDecl = new FunctionDecl( objDecl->get_name(), objDecl->get_storageClasses(), objDecl->get_linkage(), funtype, 0, objDecl->get_attributes(), objDecl->get_funcSpec() );
-                        objDecl->get_attributes().clear();
+                        FunctionDecl * newDecl = new FunctionDecl( objDecl->name, objDecl->get_storageClasses(), objDecl->linkage, funtype, 0, objDecl->attributes, objDecl->get_funcSpec() );
+                        objDecl->attributes.clear();
                         objDecl->set_type( nullptr );
                         delete objDecl;
@@ -816 +1089 @@
         }
 
-        void EliminateTypedef::premutate( CastExpr * ) {
+        void ReplaceTypedef::premutate( CastExpr * ) {
                 GuardScope( typedefNames );
-        }
-
-        void EliminateTypedef::premutate( CompoundStmt * ) {
+                GuardScope( typedeclNames );
+        }
+
+        void ReplaceTypedef::premutate( CompoundStmt * ) {
                 GuardScope( typedefNames );
+                GuardScope( typedeclNames );
                 scopeLevel += 1;
                 GuardAction( [this](){ scopeLevel -= 1; } );
         }
 
-        CompoundStmt *EliminateTypedef::postmutate( CompoundStmt * compoundStmt ) {
-                // remove and delete decl stmts
-                filter( compoundStmt->kids, [](Statement * stmt) {
-                        if ( DeclStmt *declStmt = dynamic_cast< DeclStmt * >( stmt ) ) {
-                                if ( dynamic_cast< TypedefDecl * >( declStmt->get_decl() ) ) {
-                                        return true;
-                                } // if
-                        } // if
-                        return false;
-                }, true);
-                return compoundStmt;
-        }
-
-        // there may be typedefs nested within aggregates. in order for everything to work properly, these should be removed
-        // as well
         template<typename AggDecl>
-        AggDecl *EliminateTypedef::handleAggregate( AggDecl * aggDecl ) {
-                filter( aggDecl->members, isTypedef, true );
-                return aggDecl;
-        }
-
-        template<typename AggDecl>
-        void EliminateTypedef::addImplicitTypedef( AggDecl * aggDecl ) {
+        void ReplaceTypedef::addImplicitTypedef( AggDecl * aggDecl ) {
                 if ( typedefNames.count( aggDecl->get_name() ) == 0 ) {
-                        Type *type = nullptr;
+                        Type * type = nullptr;
                         if ( StructDecl * newDeclStructDecl = dynamic_cast< StructDecl * >( aggDecl ) ) {
                                 type = new StructInstType( Type::Qualifiers(), newDeclStructDecl->get_name() );
@@ -860 +1114 @@
                         TypedefDeclPtr tyDecl( new TypedefDecl( aggDecl->get_name(), aggDecl->location, Type::StorageClasses(), type, aggDecl->get_linkage() ) );
                         typedefNames[ aggDecl->get_name() ] = std::make_pair( std::move( tyDecl ), scopeLevel );
-                } // if
-        }
-
-        void EliminateTypedef::premutate( StructDecl * structDecl ) {
+                        // add the implicit typedef to the AST
+                        declsToAddBefore.push_back( new TypedefDecl( aggDecl->get_name(), aggDecl->location, Type::StorageClasses(), type->clone(), aggDecl->get_linkage() ) );
+                } // if
+        }
+
+        template< typename AggDecl >
+        void ReplaceTypedef::handleAggregate( AggDecl * aggr ) {
+                SemanticErrorException errors;
+
+                ValueGuard< std::list<Declaration * > > oldBeforeDecls( declsToAddBefore );
+                ValueGuard< std::list<Declaration * > > oldAfterDecls ( declsToAddAfter  );
+                declsToAddBefore.clear();
+                declsToAddAfter.clear();
+
+                GuardScope( typedefNames );
+                GuardScope( typedeclNames );
+                mutateAll( aggr->parameters, * visitor );
+
+                // unroll mutateAll for aggr->members so that implicit typedefs for nested types are added to the aggregate body.
+                for ( std::list< Declaration * >::iterator i = aggr->members.begin(); i != aggr->members.end(); ++i ) {
+                        if ( !declsToAddAfter.empty() ) { aggr->members.splice( i, declsToAddAfter ); }
+
+                        try {
+                                * i = maybeMutate( * i, * visitor );
+                        } catch ( SemanticErrorException &e ) {
+                                errors.append( e );
+                        }
+
+                        if ( !declsToAddBefore.empty() ) { aggr->members.splice( i, declsToAddBefore ); }
+                }
+
+                if ( !declsToAddAfter.empty() ) { aggr->members.splice( aggr->members.end(), declsToAddAfter ); }
+                if ( !errors.isEmpty() ) { throw errors; }
+        }
+
+        void ReplaceTypedef::premutate( StructDecl * structDecl ) {
+                visit_children = false;
                 addImplicitTypedef( structDecl );
-        }
-
-
-        Declaration *EliminateTypedef::postmutate( StructDecl * structDecl ) {
-                return handleAggregate( structDecl );
-        }
-
-        void EliminateTypedef::premutate( UnionDecl * unionDecl ) {
+                handleAggregate( structDecl );
+        }
+
+        void ReplaceTypedef::premutate( UnionDecl * unionDecl ) {
+                visit_children = false;
                 addImplicitTypedef( unionDecl );
-        }
-
-        Declaration *EliminateTypedef::postmutate( UnionDecl * unionDecl ) {
-                return handleAggregate( unionDecl );
-        }
-
-        void EliminateTypedef::premutate( EnumDecl * enumDecl ) {
+                handleAggregate( unionDecl );
+        }
+
+        void ReplaceTypedef::premutate( EnumDecl * enumDecl ) {
                 addImplicitTypedef( enumDecl );
         }
 
-        Declaration *EliminateTypedef::postmutate( EnumDecl * enumDecl ) {
-                return handleAggregate( enumDecl );
-        }
-
-        Declaration *EliminateTypedef::postmutate( TraitDecl * traitDecl ) {
-                return handleAggregate( traitDecl );
-        }
-
-        void EliminateTypedef::premutate( FunctionType * ) {
+        void ReplaceTypedef::premutate( FunctionType * ) {
                 GuardValue( inFunctionType );
                 inFunctionType = true;
+        }
+
+        void ReplaceTypedef::premutate( TraitDecl * ) {
+                GuardScope( typedefNames );
+                GuardScope( typedeclNames);
         }
 
@@ -939 +1217 @@
                         for ( size_t i = 0; paramIter != params->end(); ++paramIter, ++i ) {
                                 if ( i < args.size() ) {
-                                        TypeExpr * expr = strict_dynamic_cast< TypeExpr * >( *std::next( args.begin(), i ) );
-                                        sub.add( (*paramIter)->get_name(), expr->get_type()->clone() );
+                                        TypeExpr * expr = strict_dynamic_cast< TypeExpr * >( * std::next( args.begin(), i ) );
+                                        sub.add( (* paramIter)->get_name(), expr->get_type()->clone() );
                                 } else if ( i == args.size() ) {
-                                        Type * defaultType = (*paramIter)->get_init();
+                                        Type * defaultType = (* paramIter)->get_init();
                                         if ( defaultType ) {
                                                 args.push_back( new TypeExpr( defaultType->clone() ) );
-                                                sub.add( (*paramIter)->get_name(), defaultType->clone() );
+                                                sub.add( (* paramIter)->get_name(), defaultType->clone() );
                                         }
                                 }
@@ -964 +1242 @@
         }
 
-        void CompoundLiteral::premutate( ObjectDecl *objectDecl ) {
+        void CompoundLiteral::premutate( ObjectDecl * objectDecl ) {
                 storageClasses = objectDecl->get_storageClasses();
         }
 
-        Expression *CompoundLiteral::postmutate( CompoundLiteralExpr *compLitExpr ) {
+        Expression * CompoundLiteral::postmutate( CompoundLiteralExpr * compLitExpr ) {
                 // transform [storage_class] ... (struct S){ 3, ... };
                 // into [storage_class] struct S temp =  { 3, ... };
                 static UniqueName indexName( "_compLit" );
 
-                ObjectDecl *tempvar = new ObjectDecl( indexName.newName(), storageClasses, LinkageSpec::C, nullptr, compLitExpr->get_result(), compLitExpr->get_initializer() );
+                ObjectDecl * tempvar = new ObjectDecl( indexName.newName(), storageClasses, LinkageSpec::C, nullptr, compLitExpr->get_result(), compLitExpr->get_initializer() );
                 compLitExpr->set_result( nullptr );
                 compLitExpr->set_initializer( nullptr );
@@ -1011 +1289 @@
                         TupleType * tupleType = strict_dynamic_cast< TupleType * >( ResolvExpr::extractResultType( ftype ) );
                         // ensure return value is not destructed by explicitly creating an empty ListInit node wherein maybeConstruct is false.
-                        ObjectDecl * newRet = new ObjectDecl( "", Type::StorageClasses(), LinkageSpec::Cforall, 0, tupleType, new ListInit( std::list<Initializer*>(), noDesignators, false ) );
+                        ObjectDecl * newRet = new ObjectDecl( "", Type::StorageClasses(), LinkageSpec::Cforall, 0, tupleType, new ListInit( std::list<Initializer *>(), noDesignators, false ) );
                         deleteAll( retVals );
                         retVals.clear();
@@ -1018 +1296 @@
         }
 
+        void FixObjectType::fix( std::list< Declaration * > & translationUnit ) {
+                PassVisitor<FixObjectType> fixer;
+                acceptAll( translationUnit, fixer );
+        }
+
+        void FixObjectType::previsit( ObjectDecl * objDecl ) {
+                Type * new_type = ResolvExpr::resolveTypeof( objDecl->get_type(), indexer );
+                objDecl->set_type( new_type );
+        }
+
+        void FixObjectType::previsit( FunctionDecl * funcDecl ) {
+                Type * new_type = ResolvExpr::resolveTypeof( funcDecl->type, indexer );
+                funcDecl->set_type( new_type );
+        }
+
+        void FixObjectType::previsit( TypeDecl * typeDecl ) {
+                if ( typeDecl->get_base() ) {
+                        Type * new_type = ResolvExpr::resolveTypeof( typeDecl->get_base(), indexer );
+                        typeDecl->set_base( new_type );
+                } // if
+        }
+
         void ArrayLength::computeLength( std::list< Declaration * > & translationUnit ) {
                 PassVisitor<ArrayLength> len;
@@ -1024 +1324 @@
 
         void ArrayLength::previsit( ObjectDecl * objDecl ) {
-                if ( ArrayType * at = dynamic_cast< ArrayType * >( objDecl->get_type() ) ) {
-                        if ( at->get_dimension() ) return;
-                        if ( ListInit * init = dynamic_cast< ListInit * >( objDecl->get_init() ) ) {
-                                at->set_dimension( new ConstantExpr( Constant::from_ulong( init->get_initializers().size() ) ) );
-                        }
+                if ( ArrayType * at = dynamic_cast< ArrayType * >( objDecl->type ) ) {
+                        if ( at->dimension ) return;
+                        if ( ListInit * init = dynamic_cast< ListInit * >( objDecl->init ) ) {
+                                at->dimension = new ConstantExpr( Constant::from_ulong( init->initializers.size() ) );
+                        }
+                }
+        }
+
+        void ArrayLength::previsit( ArrayType * type ) {
+                if ( type->dimension ) {
+                        // need to resolve array dimensions early so that constructor code can correctly determine
+                        // if a type is a VLA (and hence whether its elements need to be constructed)
+                        ResolvExpr::findSingleExpression( type->dimension, Validate::SizeType->clone(), indexer );
+
+                        // must re-evaluate whether a type is a VLA, now that more information is available
+                        // (e.g. the dimension may have been an enumerator, which was unknown prior to this step)
+                        type->isVarLen = ! InitTweak::isConstExpr( type->dimension );
                 }
         }
@@ -1062 +1374 @@
         }
 
-        void FindSpecialDeclarations::previsit( FunctionDecl * funcDecl ) {
-                if ( ! dereferenceOperator ) {
-                        if ( funcDecl->get_name() == "*?" && funcDecl->get_linkage() == LinkageSpec::Intrinsic ) {
-                                FunctionType * ftype = funcDecl->get_functionType();
-                                if ( ftype->get_parameters().size() == 1 && ftype->get_parameters().front()->get_type()->get_qualifiers() == Type::Qualifiers() ) {
-                                        dereferenceOperator = funcDecl;
+namespace {
+        /// Replaces enum types by int, and function/array types in function parameter and return
+        /// lists by appropriate pointers
+        struct EnumAndPointerDecay_new {
+                const ast::EnumDecl * previsit( const ast::EnumDecl * enumDecl ) {
+                        // set the type of each member of the enumeration to be EnumConstant
+                        for ( unsigned i = 0; i < enumDecl->members.size(); ++i ) {
+                                // build new version of object with EnumConstant
+                                ast::ptr< ast::ObjectDecl > obj =
+                                        enumDecl->members[i].strict_as< ast::ObjectDecl >();
+                                obj.get_and_mutate()->type =
+                                        new ast::EnumInstType{ enumDecl->name, ast::CV::Const };
+
+                                // set into decl
+                                ast::EnumDecl * mut = mutate( enumDecl );
+                                mut->members[i] = obj.get();
+                                enumDecl = mut;
+                        }
+                        return enumDecl;
+                }
+
+                static const ast::FunctionType * fixFunctionList(
+                        const ast::FunctionType * func,
+                        std::vector< ast::ptr< ast::DeclWithType > > ast::FunctionType::* field,
+                        ast::ArgumentFlag isVarArgs = ast::FixedArgs
+                ) {
+                        const auto & dwts = func->* field;
+                        unsigned nvals = dwts.size();
+                        bool hasVoid = false;
+                        for ( unsigned i = 0; i < nvals; ++i ) {
+                                func = ast::mutate_field_index( func, field, i, fixFunction( dwts[i], hasVoid ) );
+                        }
+
+                        // the only case in which "void" is valid is where it is the only one in the list
+                        if ( hasVoid && ( nvals > 1 || isVarArgs ) ) {
+                                SemanticError(
+                                        dwts.front()->location, func, "invalid type void in function type" );
+                        }
+
+                        // one void is the only thing in the list, remove it
+                        if ( hasVoid ) {
+                                func = ast::mutate_field(
+                                        func, field, std::vector< ast::ptr< ast::DeclWithType > >{} );
+                        }
+
+                        return func;
+                }
+
+                const ast::FunctionType * previsit( const ast::FunctionType * func ) {
+                        func = fixFunctionList( func, &ast::FunctionType::params, func->isVarArgs );
+                        return fixFunctionList( func, &ast::FunctionType::returns );
+                }
+        };
+
+        /// expand assertions from a trait instance, performing appropriate type variable substitutions
+        void expandAssertions(
+                const ast::TraitInstType * inst, std::vector< ast::ptr< ast::DeclWithType > > & out
+        ) {
+                assertf( inst->base, "Trait instance not linked to base trait: %s", toCString( inst ) );
+
+                // build list of trait members, substituting trait decl parameters for instance parameters
+                ast::TypeSubstitution sub{
+                        inst->base->params.begin(), inst->base->params.end(), inst->params.begin() };
+                // deliberately take ast::ptr by-value to ensure this does not mutate inst->base
+                for ( ast::ptr< ast::Decl > decl : inst->base->members ) {
+                        auto member = decl.strict_as< ast::DeclWithType >();
+                        sub.apply( member );
+                        out.emplace_back( member );
+                }
+        }
+
+        /// Associates forward declarations of aggregates with their definitions
+        class LinkReferenceToTypes_new final
+        : public ast::WithSymbolTable, public ast::WithGuards, public
+          ast::WithVisitorRef<LinkReferenceToTypes_new>, public ast::WithShortCircuiting {
+
+                // these maps of uses of forward declarations of types need to have the actual type
+                // declaration switched in * after * they have been traversed. To enable this in the
+                // ast::Pass framework, any node that needs to be so mutated has mutate() called on it
+                // before it is placed in the map, properly updating its parents in the usual traversal,
+                // then can have the actual mutation applied later
+                using ForwardEnumsType = std::unordered_multimap< std::string, ast::EnumInstType * >;
+                using ForwardStructsType = std::unordered_multimap< std::string, ast::StructInstType * >;
+                using ForwardUnionsType = std::unordered_multimap< std::string, ast::UnionInstType * >;
+
+                const CodeLocation & location;
+                const ast::SymbolTable * localSymtab;
+
+                ForwardEnumsType forwardEnums;
+                ForwardStructsType forwardStructs;
+                ForwardUnionsType forwardUnions;
+
+                /// true if currently in a generic type body, so that type parameter instances can be
+                /// renamed appropriately
+                bool inGeneric = false;
+
+        public:
+                /// contstruct using running symbol table
+                LinkReferenceToTypes_new( const CodeLocation & loc )
+                : location( loc ), localSymtab( &symtab ) {}
+
+                /// construct using provided symbol table
+                LinkReferenceToTypes_new( const CodeLocation & loc, const ast::SymbolTable & syms )
+                : location( loc ), localSymtab( &syms ) {}
+
+                const ast::Type * postvisit( const ast::TypeInstType * typeInst ) {
+                        // ensure generic parameter instances are renamed like the base type
+                        if ( inGeneric && typeInst->base ) {
+                                typeInst = ast::mutate_field(
+                                        typeInst, &ast::TypeInstType::name, typeInst->base->name );
+                        }
+
+                        if (
+                                auto typeDecl = dynamic_cast< const ast::TypeDecl * >(
+                                        localSymtab->lookupType( typeInst->name ) )
+                        ) {
+                                typeInst = ast::mutate_field( typeInst, &ast::TypeInstType::kind, typeDecl->kind );
+                        }
+
+                        return typeInst;
+                }
+
+                const ast::Type * postvisit( const ast::EnumInstType * inst ) {
+                        const ast::EnumDecl * decl = localSymtab->lookupEnum( inst->name );
+                        // not a semantic error if the enum is not found, just an implicit forward declaration
+                        if ( decl ) {
+                                inst = ast::mutate_field( inst, &ast::EnumInstType::base, decl );
+                        }
+                        if ( ! decl || ! decl->body ) {
+                                // forward declaration
+                                auto mut = mutate( inst );
+                                forwardEnums.emplace( inst->name, mut );
+                                inst = mut;
+                        }
+                        return inst;
+                }
+
+                void checkGenericParameters( const ast::ReferenceToType * inst ) {
+                        for ( const ast::Expr * param : inst->params ) {
+                                if ( ! dynamic_cast< const ast::TypeExpr * >( param ) ) {
+                                        SemanticError(
+                                                location, inst, "Expression parameters for generic types are currently "
+                                                "unsupported: " );
                                 }
                         }
                 }
-        }
+
+                const ast::StructInstType * postvisit( const ast::StructInstType * inst ) {
+                        const ast::StructDecl * decl = localSymtab->lookupStruct( inst->name );
+                        // not a semantic error if the struct is not found, just an implicit forward declaration
+                        if ( decl ) {
+                                inst = ast::mutate_field( inst, &ast::StructInstType::base, decl );
+                        }
+                        if ( ! decl || ! decl->body ) {
+                                // forward declaration
+                                auto mut = mutate( inst );
+                                forwardStructs.emplace( inst->name, mut );
+                                inst = mut;
+                        }
+                        checkGenericParameters( inst );
+                        return inst;
+                }
+
+                const ast::UnionInstType * postvisit( const ast::UnionInstType * inst ) {
+                        const ast::UnionDecl * decl = localSymtab->lookupUnion( inst->name );
+                        // not a semantic error if the struct is not found, just an implicit forward declaration
+                        if ( decl ) {
+                                inst = ast::mutate_field( inst, &ast::UnionInstType::base, decl );
+                        }
+                        if ( ! decl || ! decl->body ) {
+                                // forward declaration
+                                auto mut = mutate( inst );
+                                forwardUnions.emplace( inst->name, mut );
+                                inst = mut;
+                        }
+                        checkGenericParameters( inst );
+                        return inst;
+                }
+
+                const ast::Type * postvisit( const ast::TraitInstType * traitInst ) {
+                        // handle other traits
+                        const ast::TraitDecl * traitDecl = localSymtab->lookupTrait( traitInst->name );
+                        if ( ! traitDecl )       {
+                                SemanticError( location, "use of undeclared trait " + traitInst->name );
+                        }
+                        if ( traitDecl->params.size() != traitInst->params.size() ) {
+                                SemanticError( location, traitInst, "incorrect number of trait parameters: " );
+                        }
+                        traitInst = ast::mutate_field( traitInst, &ast::TraitInstType::base, traitDecl );
+
+                        // need to carry over the "sized" status of each decl in the instance
+                        for ( unsigned i = 0; i < traitDecl->params.size(); ++i ) {
+                                auto expr = traitInst->params[i].as< ast::TypeExpr >();
+                                if ( ! expr ) {
+                                        SemanticError(
+                                                traitInst->params[i].get(), "Expression parameters for trait instances "
+                                                "are currently unsupported: " );
+                                }
+
+                                if ( auto inst = expr->type.as< ast::TypeInstType >() ) {
+                                        if ( traitDecl->params[i]->sized && ! inst->base->sized ) {
+                                                // traitInst = ast::mutate_field_index(
+                                                //      traitInst, &ast::TraitInstType::params, i,
+                                                //      ...
+                                                // );
+                                                ast::TraitInstType * mut = ast::mutate( traitInst );
+                                                ast::chain_mutate( mut->params[i] )
+                                                        ( &ast::TypeExpr::type )
+                                                                ( &ast::TypeInstType::base )->sized = true;
+                                                traitInst = mut;
+                                        }
+                                }
+                        }
+
+                        return traitInst;
+                }
+
+                void previsit( const ast::QualifiedType * ) { visit_children = false; }
+
+                const ast::Type * postvisit( const ast::QualifiedType * qualType ) {
+                        // linking only makes sense for the "oldest ancestor" of the qualified type
+                        return ast::mutate_field(
+                                qualType, &ast::QualifiedType::parent, qualType->parent->accept( * visitor ) );
+                }
+
+                const ast::Decl * postvisit( const ast::EnumDecl * enumDecl ) {
+                        // visit enum members first so that the types of self-referencing members are updated
+                        // properly
+                        if ( ! enumDecl->body ) return enumDecl;
+
+                        // update forward declarations to point here
+                        auto fwds = forwardEnums.equal_range( enumDecl->name );
+                        if ( fwds.first != fwds.second ) {
+                                auto inst = fwds.first;
+                                do {
+                                        // forward decl is stored * mutably * in map, can thus be updated
+                                        inst->second->base = enumDecl;
+                                } while ( ++inst != fwds.second );
+                                forwardEnums.erase( fwds.first, fwds.second );
+                        }
+
+                        // ensure that enumerator initializers are properly set
+                        for ( unsigned i = 0; i < enumDecl->members.size(); ++i ) {
+                                auto field = enumDecl->members[i].strict_as< ast::ObjectDecl >();
+                                if ( field->init ) {
+                                        // need to resolve enumerator initializers early so that other passes that
+                                        // determine if an expression is constexpr have appropriate information
+                                        auto init = field->init.strict_as< ast::SingleInit >();
+
+                                        enumDecl = ast::mutate_field_index(
+                                                enumDecl, &ast::EnumDecl::members, i,
+                                                ast::mutate_field( field, &ast::ObjectDecl::init,
+                                                        ast::mutate_field( init, &ast::SingleInit::value,
+                                                                ResolvExpr::findSingleExpression(
+                                                                        init->value, new ast::BasicType{ ast::BasicType::SignedInt },
+                                                                        symtab ) ) ) );
+                                }
+                        }
+
+                        return enumDecl;
+                }
+
+                /// rename generic type parameters uniquely so that they do not conflict with user defined
+                /// function forall parameters, e.g. the T in Box and the T in f, below
+                ///   forall(otype T)
+                ///   struct Box {
+                ///     T x;
+                ///   };
+                ///   forall(otype T)
+                ///   void f(Box(T) b) {
+                ///     ...
+                ///   }
+                template< typename AggrDecl >
+                const AggrDecl * renameGenericParams( const AggrDecl * aggr ) {
+                        GuardValue( inGeneric );
+                        inGeneric = ! aggr->params.empty();
+
+                        for ( unsigned i = 0; i < aggr->params.size(); ++i ) {
+                                const ast::TypeDecl * td = aggr->params[i];
+
+                                aggr = ast::mutate_field_index(
+                                        aggr, &AggrDecl::params, i,
+                                        ast::mutate_field( td, &ast::TypeDecl::name, "__" + td->name + "_generic_" ) );
+                        }
+                        return aggr;
+                }
+
+                const ast::StructDecl * previsit( const ast::StructDecl * structDecl ) {
+                        return renameGenericParams( structDecl );
+                }
+
+                void postvisit( const ast::StructDecl * structDecl ) {
+                        // visit struct members first so that the types of self-referencing members are
+                        // updated properly
+                        if ( ! structDecl->body ) return;
+
+                        // update forward declarations to point here
+                        auto fwds = forwardStructs.equal_range( structDecl->name );
+                        if ( fwds.first != fwds.second ) {
+                                auto inst = fwds.first;
+                                do {
+                                        // forward decl is stored * mutably * in map, can thus be updated
+                                        inst->second->base = structDecl;
+                                } while ( ++inst != fwds.second );
+                                forwardStructs.erase( fwds.first, fwds.second );
+                        }
+                }
+
+                const ast::UnionDecl * previsit( const ast::UnionDecl * unionDecl ) {
+                        return renameGenericParams( unionDecl );
+                }
+
+                void postvisit( const ast::UnionDecl * unionDecl ) {
+                        // visit union members first so that the types of self-referencing members are updated
+                        // properly
+                        if ( ! unionDecl->body ) return;
+
+                        // update forward declarations to point here
+                        auto fwds = forwardUnions.equal_range( unionDecl->name );
+                        if ( fwds.first != fwds.second ) {
+                                auto inst = fwds.first;
+                                do {
+                                        // forward decl is stored * mutably * in map, can thus be updated
+                                        inst->second->base = unionDecl;
+                                } while ( ++inst != fwds.second );
+                                forwardUnions.erase( fwds.first, fwds.second );
+                        }
+                }
+
+                const ast::Decl * postvisit( const ast::TraitDecl * traitDecl ) {
+                        // set the "sized" status for the special "sized" trait
+                        if ( traitDecl->name == "sized" ) {
+                                assertf( traitDecl->params.size() == 1, "Built-in trait 'sized' has incorrect "
+                                        "number of parameters: %zd", traitDecl->params.size() );
+
+                                traitDecl = ast::mutate_field_index(
+                                        traitDecl, &ast::TraitDecl::params, 0,
+                                        ast::mutate_field(
+                                                traitDecl->params.front().get(), &ast::TypeDecl::sized, true ) );
+                        }
+
+                        // move assertions from type parameters into the body of the trait
+                        std::vector< ast::ptr< ast::DeclWithType > > added;
+                        for ( const ast::TypeDecl * td : traitDecl->params ) {
+                                for ( const ast::DeclWithType * assn : td->assertions ) {
+                                        auto inst = dynamic_cast< const ast::TraitInstType * >( assn->get_type() );
+                                        if ( inst ) {
+                                                expandAssertions( inst, added );
+                                        } else {
+                                                added.emplace_back( assn );
+                                        }
+                                }
+                        }
+                        if ( ! added.empty() ) {
+                                auto mut = mutate( traitDecl );
+                                for ( const ast::DeclWithType * decl : added ) {
+                                        mut->members.emplace_back( decl );
+                                }
+                                traitDecl = mut;
+                        }
+
+                        return traitDecl;
+                }
+        };
+
+        /// Replaces array and function types in forall lists by appropriate pointer type and assigns
+        /// each object and function declaration a unique ID
+        class ForallPointerDecay_new {
+                const CodeLocation & location;
+        public:
+                ForallPointerDecay_new( const CodeLocation & loc ) : location( loc ) {}
+
+                const ast::ObjectDecl * previsit( const ast::ObjectDecl * obj ) {
+                        // ensure that operator names only apply to functions or function pointers
+                        if (
+                                CodeGen::isOperator( obj->name )
+                                && ! dynamic_cast< const ast::FunctionType * >( obj->type->stripDeclarator() )
+                        ) {
+                                SemanticError( obj->location, toCString( "operator ", obj->name.c_str(), " is not "
+                                        "a function or function pointer." )  );
+                        }
+
+                        // ensure object has unique ID
+                        if ( obj->uniqueId ) return obj;
+                        auto mut = mutate( obj );
+                        mut->fixUniqueId();
+                        return mut;
+                }
+
+                const ast::FunctionDecl * previsit( const ast::FunctionDecl * func ) {
+                        // ensure function has unique ID
+                        if ( func->uniqueId ) return func;
+                        auto mut = mutate( func );
+                        mut->fixUniqueId();
+                        return mut;
+                }
+
+                /// Fix up assertions -- flattens assertion lists, removing all trait instances
+                template< typename node_t, typename parent_t >
+                static const node_t * forallFixer(
+                        const CodeLocation & loc, const node_t * node,
+                        ast::ParameterizedType::ForallList parent_t::* forallField
+                ) {
+                        for ( unsigned i = 0; i < (node->* forallField).size(); ++i ) {
+                                const ast::TypeDecl * type = (node->* forallField)[i];
+                                if ( type->assertions.empty() ) continue;
+
+                                std::vector< ast::ptr< ast::DeclWithType > > asserts;
+                                asserts.reserve( type->assertions.size() );
+
+                                // expand trait instances into their members
+                                for ( const ast::DeclWithType * assn : type->assertions ) {
+                                        auto traitInst =
+                                                dynamic_cast< const ast::TraitInstType * >( assn->get_type() );
+                                        if ( traitInst ) {
+                                                // expand trait instance to all its members
+                                                expandAssertions( traitInst, asserts );
+                                        } else {
+                                                // pass other assertions through
+                                                asserts.emplace_back( assn );
+                                        }
+                                }
+
+                                // apply FixFunction to every assertion to check for invalid void type
+                                for ( ast::ptr< ast::DeclWithType > & assn : asserts ) {
+                                        bool isVoid = false;
+                                        assn = fixFunction( assn, isVoid );
+                                        if ( isVoid ) {
+                                                SemanticError( loc, node, "invalid type void in assertion of function " );
+                                        }
+                                }
+
+                                // place mutated assertion list in node
+                                auto mut = mutate( type );
+                                mut->assertions = move( asserts );
+                                node = ast::mutate_field_index( node, forallField, i, mut );
+                        }
+                        return node;
+                }
+
+                const ast::FunctionType * previsit( const ast::FunctionType * ftype ) {
+                        return forallFixer( location, ftype, &ast::FunctionType::forall );
+                }
+
+                const ast::StructDecl * previsit( const ast::StructDecl * aggrDecl ) {
+                        return forallFixer( aggrDecl->location, aggrDecl, &ast::StructDecl::params );
+                }
+
+                const ast::UnionDecl * previsit( const ast::UnionDecl * aggrDecl ) {
+                        return forallFixer( aggrDecl->location, aggrDecl, &ast::UnionDecl::params );
+                }
+        };
+} // anonymous namespace
+
+const ast::Type * validateType(
+                const CodeLocation & loc, const ast::Type * type, const ast::SymbolTable & symtab ) {
+        ast::Pass< EnumAndPointerDecay_new > epc;
+        ast::Pass< LinkReferenceToTypes_new > lrt{ loc, symtab };
+        ast::Pass< ForallPointerDecay_new > fpd{ loc };
+
+        return type->accept( epc )->accept( lrt )->accept( fpd );
+}
+
 } // namespace SymTab