//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// CommonType.cc --
//
// Author           : Richard C. Bilson
// Created On       : Sun May 17 06:59:27 2015
// Last Modified By : Peter A. Buhr
// Last Modified On : Thu Feb 14 17:10:10 2019
// Update Count     : 24
//

#include "CommonType.hpp"

#include <cassert>                       // for strict_dynamic_cast
#include <map>                           // for _Rb_tree_const_iterator
#include <utility>                       // for pair

#include "AST/Decl.hpp"
#include "AST/Pass.hpp"
#include "AST/Type.hpp"
#include "Unify.h"                       // for unifyExact, WidenMode
#include "typeops.h"                     // for isFtype
#include "Tuples/Tuples.h"

// #define DEBUG
#ifdef DEBUG
#define PRINT(x) x
#else
#define PRINT(x)
#endif

namespace ResolvExpr {

namespace {

	// GENERATED START, DO NOT EDIT
	// GENERATED BY BasicTypes-gen.cc
	#define BT ast::BasicKind::
	static const ast::BasicKind commonTypes[BT NUMBER_OF_BASIC_TYPES][BT NUMBER_OF_BASIC_TYPES] = { // nearest common ancestor
		/*		                        B                       C                      SC                      UC                      SI                     SUI
				                        I                      UI                      LI                     LUI                     LLI                    LLUI
				                       IB                     UIB                     _FH                     _FH                      _F                     _FC
				                        F                      FC                     _FX                    _FXC                      FD                    _FDC
				                        D                      DC                    F80X                   _FDXC                     F80                     _FB
				                    _FLDC                      FB                      LD                     LDC                    _FBX                  _FLDXC
				 */
				  {
		/*      B */                BT Bool,                BT Char,          BT SignedChar,        BT UnsignedChar,      BT ShortSignedInt,    BT ShortUnsignedInt,
				             BT SignedInt,         BT UnsignedInt,       BT LongSignedInt,     BT LongUnsignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*      C */                BT Char,                BT Char,          BT SignedChar,        BT UnsignedChar,      BT ShortSignedInt,    BT ShortUnsignedInt,
				             BT SignedInt,         BT UnsignedInt,       BT LongSignedInt,     BT LongUnsignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*     SC */          BT SignedChar,          BT SignedChar,          BT SignedChar,        BT UnsignedChar,      BT ShortSignedInt,    BT ShortUnsignedInt,
				             BT SignedInt,         BT UnsignedInt,       BT LongSignedInt,     BT LongUnsignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*     UC */        BT UnsignedChar,        BT UnsignedChar,        BT UnsignedChar,        BT UnsignedChar,      BT ShortSignedInt,    BT ShortUnsignedInt,
				             BT SignedInt,         BT UnsignedInt,       BT LongSignedInt,     BT LongUnsignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*     SI */      BT ShortSignedInt,      BT ShortSignedInt,      BT ShortSignedInt,      BT ShortSignedInt,      BT ShortSignedInt,    BT ShortUnsignedInt,
				             BT SignedInt,         BT UnsignedInt,       BT LongSignedInt,     BT LongUnsignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*    SUI */    BT ShortUnsignedInt,    BT ShortUnsignedInt,    BT ShortUnsignedInt,    BT ShortUnsignedInt,    BT ShortUnsignedInt,    BT ShortUnsignedInt,
				             BT SignedInt,         BT UnsignedInt,       BT LongSignedInt,     BT LongUnsignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*      I */           BT SignedInt,           BT SignedInt,           BT SignedInt,           BT SignedInt,           BT SignedInt,           BT SignedInt,
				             BT SignedInt,         BT UnsignedInt,       BT LongSignedInt,     BT LongUnsignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*     UI */         BT UnsignedInt,         BT UnsignedInt,         BT UnsignedInt,         BT UnsignedInt,         BT UnsignedInt,         BT UnsignedInt,
				           BT UnsignedInt,         BT UnsignedInt,       BT LongSignedInt,     BT LongUnsignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*     LI */       BT LongSignedInt,       BT LongSignedInt,       BT LongSignedInt,       BT LongSignedInt,       BT LongSignedInt,       BT LongSignedInt,
				         BT LongSignedInt,       BT LongSignedInt,       BT LongSignedInt,     BT LongUnsignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*    LUI */     BT LongUnsignedInt,     BT LongUnsignedInt,     BT LongUnsignedInt,     BT LongUnsignedInt,     BT LongUnsignedInt,     BT LongUnsignedInt,
				       BT LongUnsignedInt,     BT LongUnsignedInt,     BT LongUnsignedInt,     BT LongUnsignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*    LLI */   BT LongLongSignedInt,   BT LongLongSignedInt,   BT LongLongSignedInt,   BT LongLongSignedInt,   BT LongLongSignedInt,   BT LongLongSignedInt,
				     BT LongLongSignedInt,   BT LongLongSignedInt,   BT LongLongSignedInt,   BT LongLongSignedInt,   BT LongLongSignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*   LLUI */ BT LongLongUnsignedInt, BT LongLongUnsignedInt, BT LongLongUnsignedInt, BT LongLongUnsignedInt, BT LongLongUnsignedInt, BT LongLongUnsignedInt,
				   BT LongLongUnsignedInt, BT LongLongUnsignedInt, BT LongLongUnsignedInt, BT LongLongUnsignedInt, BT LongLongUnsignedInt, BT LongLongUnsignedInt,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*     IB */        BT SignedInt128,        BT SignedInt128,        BT SignedInt128,        BT SignedInt128,        BT SignedInt128,        BT SignedInt128,
				          BT SignedInt128,        BT SignedInt128,        BT SignedInt128,        BT SignedInt128,        BT SignedInt128,        BT SignedInt128,
				          BT SignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*    UIB */      BT UnsignedInt128,      BT UnsignedInt128,      BT UnsignedInt128,      BT UnsignedInt128,      BT UnsignedInt128,      BT UnsignedInt128,
				        BT UnsignedInt128,      BT UnsignedInt128,      BT UnsignedInt128,      BT UnsignedInt128,      BT UnsignedInt128,      BT UnsignedInt128,
				        BT UnsignedInt128,      BT UnsignedInt128,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*    _FH */            BT uFloat16,            BT uFloat16,            BT uFloat16,            BT uFloat16,            BT uFloat16,            BT uFloat16,
				              BT uFloat16,            BT uFloat16,            BT uFloat16,            BT uFloat16,            BT uFloat16,            BT uFloat16,
				              BT uFloat16,            BT uFloat16,            BT uFloat16,     BT uFloat16Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*    _FH */     BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat16Complex,
				       BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat16Complex,
				       BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat16Complex,     BT uFloat32Complex,     BT uFloat32Complex,
				          BT FloatComplex,        BT FloatComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,     BT uFloat64Complex,     BT uFloat64Complex,
				         BT DoubleComplex,       BT DoubleComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				  },
				  {
		/*     _F */            BT uFloat32,            BT uFloat32,            BT uFloat32,            BT uFloat32,            BT uFloat32,            BT uFloat32,
				              BT uFloat32,            BT uFloat32,            BT uFloat32,            BT uFloat32,            BT uFloat32,            BT uFloat32,
				              BT uFloat32,            BT uFloat32,            BT uFloat32,     BT uFloat32Complex,            BT uFloat32,     BT uFloat32Complex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*    _FC */     BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,
				       BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,
				       BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,     BT uFloat32Complex,
				          BT FloatComplex,        BT FloatComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,     BT uFloat64Complex,     BT uFloat64Complex,
				         BT DoubleComplex,       BT DoubleComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				  },
				  {
		/*      F */               BT Float,               BT Float,               BT Float,               BT Float,               BT Float,               BT Float,
				                 BT Float,               BT Float,               BT Float,               BT Float,               BT Float,               BT Float,
				                 BT Float,               BT Float,               BT Float,        BT FloatComplex,               BT Float,        BT FloatComplex,
				                 BT Float,        BT FloatComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*     FC */        BT FloatComplex,        BT FloatComplex,        BT FloatComplex,        BT FloatComplex,        BT FloatComplex,        BT FloatComplex,
				          BT FloatComplex,        BT FloatComplex,        BT FloatComplex,        BT FloatComplex,        BT FloatComplex,        BT FloatComplex,
				          BT FloatComplex,        BT FloatComplex,        BT FloatComplex,        BT FloatComplex,        BT FloatComplex,        BT FloatComplex,
				          BT FloatComplex,        BT FloatComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,     BT uFloat64Complex,     BT uFloat64Complex,
				         BT DoubleComplex,       BT DoubleComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				  },
				  {
		/*    _FX */           BT uFloat32x,           BT uFloat32x,           BT uFloat32x,           BT uFloat32x,           BT uFloat32x,           BT uFloat32x,
				             BT uFloat32x,           BT uFloat32x,           BT uFloat32x,           BT uFloat32x,           BT uFloat32x,           BT uFloat32x,
				             BT uFloat32x,           BT uFloat32x,           BT uFloat32x,    BT uFloat32xComplex,           BT uFloat32x,    BT uFloat32xComplex,
				             BT uFloat32x,    BT uFloat32xComplex,           BT uFloat32x,    BT uFloat32xComplex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*   _FXC */    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,
				      BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,
				      BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,
				      BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,    BT uFloat32xComplex,     BT uFloat64Complex,     BT uFloat64Complex,
				         BT DoubleComplex,       BT DoubleComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				  },
				  {
		/*     FD */            BT uFloat64,            BT uFloat64,            BT uFloat64,            BT uFloat64,            BT uFloat64,            BT uFloat64,
				              BT uFloat64,            BT uFloat64,            BT uFloat64,            BT uFloat64,            BT uFloat64,            BT uFloat64,
				              BT uFloat64,            BT uFloat64,            BT uFloat64,     BT uFloat64Complex,            BT uFloat64,     BT uFloat64Complex,
				              BT uFloat64,     BT uFloat64Complex,            BT uFloat64,     BT uFloat64Complex,            BT uFloat64,     BT uFloat64Complex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*   _FDC */     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,
				       BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,
				       BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,
				       BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,     BT uFloat64Complex,
				         BT DoubleComplex,       BT DoubleComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				  },
				  {
		/*      D */              BT Double,              BT Double,              BT Double,              BT Double,              BT Double,              BT Double,
				                BT Double,              BT Double,              BT Double,              BT Double,              BT Double,              BT Double,
				                BT Double,              BT Double,              BT Double,       BT DoubleComplex,              BT Double,       BT DoubleComplex,
				                BT Double,       BT DoubleComplex,              BT Double,       BT DoubleComplex,              BT Double,       BT DoubleComplex,
				                BT Double,       BT DoubleComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*     DC */       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,
				         BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,
				         BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,
				         BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,       BT DoubleComplex,
				         BT DoubleComplex,       BT DoubleComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				  },
				  {
		/*   F80X */           BT uFloat64x,           BT uFloat64x,           BT uFloat64x,           BT uFloat64x,           BT uFloat64x,           BT uFloat64x,
				             BT uFloat64x,           BT uFloat64x,           BT uFloat64x,           BT uFloat64x,           BT uFloat64x,           BT uFloat64x,
				             BT uFloat64x,           BT uFloat64x,           BT uFloat64x,    BT uFloat64xComplex,           BT uFloat64x,    BT uFloat64xComplex,
				             BT uFloat64x,    BT uFloat64xComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uFloat64x,    BT uFloat64xComplex,
				             BT uFloat64x,    BT uFloat64xComplex,           BT uFloat64x,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*  _FDXC */    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,
				      BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,
				      BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,
				      BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,
				      BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat64xComplex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				  },
				  {
		/*    F80 */           BT uuFloat80,           BT uuFloat80,           BT uuFloat80,           BT uuFloat80,           BT uuFloat80,           BT uuFloat80,
				             BT uuFloat80,           BT uuFloat80,           BT uuFloat80,           BT uuFloat80,           BT uuFloat80,           BT uuFloat80,
				             BT uuFloat80,           BT uuFloat80,           BT uuFloat80,    BT uFloat64xComplex,           BT uuFloat80,    BT uFloat64xComplex,
				             BT uuFloat80,    BT uFloat64xComplex,           BT uuFloat80,    BT uFloat64xComplex,           BT uuFloat80,    BT uFloat64xComplex,
				             BT uuFloat80,    BT uFloat64xComplex,           BT uuFloat80,    BT uFloat64xComplex,           BT uuFloat80,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*    _FB */           BT uFloat128,           BT uFloat128,           BT uFloat128,           BT uFloat128,           BT uFloat128,           BT uFloat128,
				             BT uFloat128,           BT uFloat128,           BT uFloat128,           BT uFloat128,           BT uFloat128,           BT uFloat128,
				             BT uFloat128,           BT uFloat128,           BT uFloat128,    BT uFloat128Complex,           BT uFloat128,    BT uFloat128Complex,
				             BT uFloat128,    BT uFloat128Complex,           BT uFloat128,    BT uFloat128Complex,           BT uFloat128,    BT uFloat128Complex,
				             BT uFloat128,    BT uFloat128Complex,           BT uFloat128,    BT uFloat128Complex,           BT uFloat128,           BT uFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*  _FLDC */    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,    BT uFloat128Complex,
				      BT uFloat128Complex,    BT uFloat128Complex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				  },
				  {
		/*     FB */          BT uuFloat128,          BT uuFloat128,          BT uuFloat128,          BT uuFloat128,          BT uuFloat128,          BT uuFloat128,
				            BT uuFloat128,          BT uuFloat128,          BT uuFloat128,          BT uuFloat128,          BT uuFloat128,          BT uuFloat128,
				            BT uuFloat128,          BT uuFloat128,          BT uuFloat128,    BT uFloat128Complex,          BT uuFloat128,    BT uFloat128Complex,
				            BT uuFloat128,    BT uFloat128Complex,          BT uuFloat128,    BT uFloat128Complex,          BT uuFloat128,    BT uFloat128Complex,
				            BT uuFloat128,    BT uFloat128Complex,          BT uuFloat128,    BT uFloat128Complex,          BT uuFloat128,          BT uuFloat128,
				      BT uFloat128Complex,          BT uuFloat128,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*     LD */          BT LongDouble,          BT LongDouble,          BT LongDouble,          BT LongDouble,          BT LongDouble,          BT LongDouble,
				            BT LongDouble,          BT LongDouble,          BT LongDouble,          BT LongDouble,          BT LongDouble,          BT LongDouble,
				            BT LongDouble,          BT LongDouble,          BT LongDouble,   BT LongDoubleComplex,          BT LongDouble,   BT LongDoubleComplex,
				            BT LongDouble,   BT LongDoubleComplex,          BT LongDouble,   BT LongDoubleComplex,          BT LongDouble,   BT LongDoubleComplex,
				            BT LongDouble,   BT LongDoubleComplex,          BT LongDouble,   BT LongDoubleComplex,          BT LongDouble,          BT LongDouble,
				     BT LongDoubleComplex,          BT LongDouble,          BT LongDouble,   BT LongDoubleComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/*    LDC */   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,
				     BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,
				     BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,
				     BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,
				     BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,
				     BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT LongDoubleComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				  },
				  {
		/*   _FBX */          BT uFloat128x,          BT uFloat128x,          BT uFloat128x,          BT uFloat128x,          BT uFloat128x,          BT uFloat128x,
				            BT uFloat128x,          BT uFloat128x,          BT uFloat128x,          BT uFloat128x,          BT uFloat128x,          BT uFloat128x,
				            BT uFloat128x,          BT uFloat128x,          BT uFloat128x,   BT uFloat128xComplex,          BT uFloat128x,   BT uFloat128xComplex,
				            BT uFloat128x,   BT uFloat128xComplex,          BT uFloat128x,   BT uFloat128xComplex,          BT uFloat128x,   BT uFloat128xComplex,
				            BT uFloat128x,   BT uFloat128xComplex,          BT uFloat128x,   BT uFloat128xComplex,          BT uFloat128x,          BT uFloat128x,
				     BT uFloat128xComplex,          BT uFloat128x,          BT uFloat128x,   BT uFloat128xComplex,          BT uFloat128x,   BT uFloat128xComplex,
				  },
				  {
		/* _FLDXC */   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				     BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				     BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				     BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				     BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				     BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,   BT uFloat128xComplex,
				  },
	}; // commonTypes
	#undef BT
	// GENERATED END
	static_assert(
		sizeof(commonTypes)/sizeof(commonTypes[0][0]) == ast::BasicKind::NUMBER_OF_BASIC_TYPES * ast::BasicKind::NUMBER_OF_BASIC_TYPES,
		"Each basic type kind should have a corresponding row in the combined type matrix"
	);

class CommonType final : public ast::WithShortCircuiting {
	const ast::Type * type2;
	WidenMode widen;
	ast::TypeEnvironment & tenv;
	const ast::OpenVarSet & open;
	ast::AssertionSet & need;
	ast::AssertionSet & have;
public:
	static size_t traceId;
	ast::ptr< ast::Type > result;

	CommonType(
		const ast::Type * t2, WidenMode w,
		ast::TypeEnvironment & env, const ast::OpenVarSet & o,
		ast::AssertionSet & need, ast::AssertionSet & have )
	: type2( t2 ), widen( w ), tenv( env ), open( o ), need (need), have (have) ,result() {}

	void previsit( const ast::Node * ) { visit_children = false; }

	void postvisit( const ast::VoidType * ) {}

	void postvisit( const ast::BasicType * basic ) {
		if ( auto basic2 = dynamic_cast< const ast::BasicType * >( type2 ) ) {
			ast::BasicKind kind;
			if (basic->kind != basic2->kind && !widen.first && !widen.second) return;
			else if (!widen.first) kind = basic->kind; // widen.second
			else if (!widen.second) kind = basic2->kind;
			else kind = commonTypes[ basic->kind ][ basic2->kind ];
			// xxx - what does qualifiers even do here??
			if ( (basic->qualifiers >= basic2->qualifiers || widen.first)
				&& (basic->qualifiers <= basic2->qualifiers || widen.second) ) {
				result = new ast::BasicType{ kind, basic->qualifiers | basic2->qualifiers };
			}
		} else if (
			dynamic_cast< const ast::ZeroType * >( type2 )
			|| dynamic_cast< const ast::OneType * >( type2 )
		) {
			if (widen.second) {
				result = new ast::BasicType{ basic->kind, basic->qualifiers | type2->qualifiers };
			}
		} else if ( const ast::EnumInstType * enumInst = dynamic_cast< const ast::EnumInstType * >( type2 ) ) {
			const ast::EnumDecl* enumDecl = enumInst->base;
			if ( !enumDecl->base ) {
				ast::BasicKind kind = commonTypes[ basic->kind ][ ast::BasicKind::SignedInt ];
				if (
					( ( kind == basic->kind && basic->qualifiers >= type2->qualifiers )
						|| widen.first )
					&& ( ( kind != basic->kind && basic->qualifiers <= type2->qualifiers )
						|| widen.second )
				) {
					result = new ast::BasicType{ kind, basic->qualifiers | type2->qualifiers };
				}
			}
		} else if ( auto type2AsAttr = dynamic_cast< const ast::EnumAttrType * >( type2 ) ) {
			if ( type2AsAttr->attr == ast::EnumAttribute::Posn ) {
				ast::BasicKind kind = commonTypes[ basic->kind ][ ast::BasicKind::SignedInt ];
				if (
					( ( kind == basic->kind && basic->qualifiers >= type2->qualifiers )
						|| widen.first )
					&& ( ( kind != basic->kind && basic->qualifiers <= type2->qualifiers )
						|| widen.second )
				) {
					result = new ast::BasicType{ kind, basic->qualifiers | type2->qualifiers };
				}
			}
		}
	}

private:
	template< typename Pointer >
	void getCommonWithVoidPointer( const Pointer * voidPtr, const Pointer * oPtr ) {
		const ast::Type * base = oPtr->base;
		if ( auto var = dynamic_cast< const ast::TypeInstType * >( base ) ) {
			auto entry = open.find( *var );
			if ( entry != open.end() ) {
				ast::AssertionSet need, have;
				if ( ! tenv.bindVar(
					var, voidPtr->base, entry->second, need, have, open, widen )
				) return;
			}
		}
		result = voidPtr;
		add_qualifiers( result, oPtr->qualifiers );
	}

public:
	void postvisit( const ast::PointerType * pointer ) {
		if ( auto pointer2 = dynamic_cast< const ast::PointerType * >( type2 ) ) {
			if (
				widen.first
				&& pointer2->base.as< ast::VoidType >()
				&& ! ast::isFtype( pointer->base )
			) {
				getCommonWithVoidPointer( pointer2, pointer );
			} else if (
				widen.second
				&& pointer->base.as< ast::VoidType >()
				&& ! ast::isFtype( pointer2->base )
			) {
				getCommonWithVoidPointer( pointer, pointer2 );
			} else if (
				( pointer->base->qualifiers >= pointer2->base->qualifiers || widen.first )
				&& ( pointer->base->qualifiers <= pointer2->base->qualifiers || widen.second )
			) {
				ast::CV::Qualifiers q1 = pointer->base->qualifiers;
				ast::CV::Qualifiers q2 = pointer2->base->qualifiers;

				// force t{1,2} to be cloned if their qualifiers must be stripped, so that
				// pointer{,2}->base are unchanged
				ast::ptr< ast::Type > t1{ pointer->base }, t2{ pointer2->base };
				reset_qualifiers( t1 );
				reset_qualifiers( t2 );

				ast::OpenVarSet newOpen{ open };
				if ( unifyExact( t1, t2, tenv, have, need, newOpen, noWiden() ) ) {
					result = pointer;
					if ( q1.val != q2.val ) {
						// reset result->base->qualifiers to be union of two base qualifiers
						strict_dynamic_cast< ast::PointerType * >(
							result.get_and_mutate()
						)->base.get_and_mutate()->qualifiers = q1 | q2;
					}
				} else if ( isFtype (t1) && isFtype (t2) ) {
					auto f1 = t1.as<ast::FunctionType>();
					if (!f1) return;
					auto f2 = t2.strict_as<ast::FunctionType>();

					assertf(f1->returns.size() <= 1, "Function return should not be a list");
					assertf(f2->returns.size() <= 1, "Function return should not be a list");

					if (
						( f1->params.size() != f2->params.size() || f1->returns.size() != f2->returns.size() )
						&& ! f1->isTtype()
						&& ! f2->isTtype()
					) return;

					auto params1 = flattenList( f1->params, tenv );
					auto params2 = flattenList( f2->params, tenv );

					auto crnt1 = params1.begin();
					auto crnt2 = params2.begin();
					auto end1 = params1.end();
					auto end2 = params2.end();

					while (crnt1 != end1 && crnt2 != end2 ) {
						const ast::Type * arg1 = *crnt1;
						const ast::Type * arg2 = *crnt2;

						bool isTuple1 = Tuples::isTtype( t1 );
						bool isTuple2 = Tuples::isTtype( t2 );

						// assumes here that ttype *must* be last parameter
						if ( isTuple1 && ! isTuple2 ) {
							// combine remainder of list2, then unify
							if (unifyExact(
								arg1, tupleFromTypes( crnt2, end2 ), tenv, need, have, open,
								noWiden() )) {
									break;
							} else return;
						} else if ( ! isTuple1 && isTuple2 ) {
							// combine remainder of list1, then unify
							if (unifyExact(
								tupleFromTypes( crnt1, end1 ), arg2, tenv, need, have, open,
								noWiden() )) {
									break;
							} else return;
						}

						// allow qualifiers of pointer and reference base to become more specific
						if (auto ref1 = dynamic_cast<const ast::ReferenceType *> (arg1)) {
							if (auto ref2 = dynamic_cast<const ast::ReferenceType *> (arg2)) {
								ast::ptr<ast::Type> base1 = ref1->base;
								ast::ptr<ast::Type> base2 = ref2->base;

								// xxx - assume LHS is always the target type

								if ( ! ((widen.second && ref2->qualifiers.is_mutex)
								|| (ref1->qualifiers.is_mutex == ref2->qualifiers.is_mutex ))) return;

								if ( (widen.second && base1->qualifiers <= base2->qualifiers ) || (base2->qualifiers == base1->qualifiers) ) {

									reset_qualifiers(base1);
									reset_qualifiers(base2);

									if ( !unifyExact(
										base1, base2, tenv, need, have, open, noWiden() )
									) return;
								}
							} else return;
						} else if (auto ptr1 = dynamic_cast<const ast::PointerType *> (arg1)) {
							if (auto ptr2 = dynamic_cast<const ast::PointerType *> (arg2)) {
								ast::ptr<ast::Type> base1 = ptr1->base;
								ast::ptr<ast::Type> base2 = ptr2->base;

								// xxx - assume LHS is always the target type
								// a function accepting const can always be called by non-const arg

								if ( (widen.second && base1->qualifiers <= base2->qualifiers ) || (base2->qualifiers == base1->qualifiers) ) {

									reset_qualifiers(base1);
									reset_qualifiers(base2);

									if ( ! unifyExact(
										base1, base2, tenv, need, have, open, noWiden() )
									) return;
								}
							} else return;
						} else if (! unifyExact(
								arg1, arg2, tenv, need, have, open, noWiden() )) {
							return;
						}
						++crnt1; ++crnt2;
					}
					if ( crnt1 != end1 ) {
						// try unifying empty tuple with ttype
						const ast::Type * t1 = *crnt1;
						if (! Tuples::isTtype( t1 ) ) return;
						if (! unifyExact(
							t1, tupleFromTypes( crnt2, end2 ), tenv, need, have, open,
							noWiden() )) return;
					} else if ( crnt2 != end2 ) {
						// try unifying empty tuple with ttype
						const ast::Type * t2 = *crnt2;
						if ( !Tuples::isTtype( t2 ) ) return;
						if ( !unifyExact(
							tupleFromTypes( crnt1, end1 ), t2, tenv, need, have, open,
							noWiden() )) return;
					}
					if ((f1->returns.size() == 0 && f2->returns.size() == 0)
					  || (f1->returns.size() == 1 && f2->returns.size() == 1 && unifyExact(f1->returns[0], f2->returns[0], tenv, need, have, open, noWiden()))) {
						result = pointer;

						for (auto & assn : f1->assertions) {
							auto i = need.find(assn);
							if (i != need.end()) i->second.isUsed = true;
							auto j = have.find(assn);
							if (j != have.end()) j->second.isUsed = true;
						}

						for (auto & assn : f2->assertions) {
							auto i = need.find(assn);
							if (i != need.end()) i->second.isUsed = true;
							auto j = have.find(assn);
							if (j != have.end()) j->second.isUsed = true;
						}
					}
				} // if ftype
			}
		} else if ( widen.second && dynamic_cast< const ast::ZeroType * >( type2 ) ) {
			result = pointer;
			add_qualifiers( result, type2->qualifiers );
		}
	}

	void postvisit( const ast::ArrayType * ) {}

	void postvisit( const ast::ReferenceType * ref ) {
		if ( auto ref2 = dynamic_cast< const ast::ReferenceType * >( type2 ) ) {
			if (
				widen.first && ref2->base.as< ast::VoidType >() && ! ast::isFtype( ref->base )
			) {
				getCommonWithVoidPointer( ref2, ref );
			} else if (
				widen.second && ref->base.as< ast::VoidType>() && ! ast::isFtype( ref2->base )
			) {
				getCommonWithVoidPointer( ref, ref2 );
			} else if (
				( ref->base->qualifiers >= ref2->base->qualifiers || widen.first )
				&& ( ref->base->qualifiers <= ref2->base->qualifiers || widen.second )
			) {
				ast::CV::Qualifiers q1 = ref->base->qualifiers, q2 = ref2->base->qualifiers;

				// force t{1,2} to be cloned if their qualifiers must be stripped, so that
				// ref{,2}->base are unchanged
				ast::ptr< ast::Type > t1{ ref->base }, t2{ ref2->base };
				reset_qualifiers( t1 );
				reset_qualifiers( t2 );

				ast::OpenVarSet newOpen{ open };
				if ( unifyExact( t1, t2, tenv, have, need, newOpen, noWiden() ) ) {
					result = ref;
					if ( q1.val != q2.val ) {
						// reset result->base->qualifiers to be union of two base qualifiers
						strict_dynamic_cast< ast::ReferenceType * >(
							result.get_and_mutate()
						)->base.get_and_mutate()->qualifiers = q1 | q2;
					}
				}
			}
		} else if ( widen.second && dynamic_cast< const ast::ZeroType * >( type2 ) ) {
			result = ref;
			add_qualifiers( result, type2->qualifiers );
		} else {
			if (!dynamic_cast<const ast::EnumInstType *>(type2))
				result = commonType( type2, ref, tenv, need, have, open, widen );
		}
	}

	void postvisit( const ast::FunctionType * ) {}

	void postvisit( const ast::StructInstType * ) {}

	void postvisit( const ast::UnionInstType * ) {}

	void postvisit( const ast::EnumInstType * enumInst ) {
		if ( enumInst->base && !enumInst->base->base ) {
			auto basicType = new ast::BasicType( ast::BasicKind::UnsignedInt );
			result = commonType( basicType, type2, tenv, need, have, open, widen);
		}
	}

	void postvisit( const ast::EnumAttrType * ) {}

	void postvisit( const ast::TraitInstType * ) {}

	void postvisit( const ast::TypeInstType * ) {}

	void postvisit( const ast::TupleType * ) {}

	void postvisit( const ast::VarArgsType * ) {}

	void postvisit( const ast::ZeroType * zero ) {
		if ( !widen.first ) return;
		if ( dynamic_cast< const ast::BasicType * >( type2 )
				|| dynamic_cast< const ast::PointerType * >( type2 ) ) {
			if ( widen.second || zero->qualifiers <= type2->qualifiers ) {
				result = type2;
				add_qualifiers( result, zero->qualifiers );
			}
		} else if ( widen.second && dynamic_cast< const ast::OneType * >( type2 ) ) {
			result = new ast::BasicType{
				ast::BasicKind::SignedInt, zero->qualifiers | type2->qualifiers };
		} else if ( const ast::EnumInstType * enumInst = dynamic_cast< const ast::EnumInstType * >( type2 ) ) {
			const ast::EnumDecl * enumDecl = enumInst->base;
			if ( !enumDecl->base ) {
				if ( widen.second || zero->qualifiers <= type2->qualifiers ) {
					result = type2;
					add_qualifiers( result, zero->qualifiers );
				}
			}
		}
	}

	void postvisit( const ast::OneType * one ) {
		if ( !widen.first ) return;
		if ( dynamic_cast< const ast::BasicType * >( type2 ) ) {
			if ( widen.second || one->qualifiers <= type2->qualifiers ) {
				result = type2;
				add_qualifiers( result, one->qualifiers );
			}
		} else if ( widen.second && dynamic_cast< const ast::ZeroType * >( type2 ) ) {
			result = new ast::BasicType{
				ast::BasicKind::SignedInt, one->qualifiers | type2->qualifiers };
		} else if ( const ast::EnumInstType * enumInst = dynamic_cast< const ast::EnumInstType * >( type2 ) ) {
			const ast::EnumDecl * enumDecl = enumInst->base;
			if ( !enumDecl->base ) {
				if ( widen.second || one->qualifiers <= type2->qualifiers ) {
					result = type2;
					add_qualifiers( result, one->qualifiers );
				}
			}
		}
	}
};

// size_t CommonType::traceId = Stats::Heap::new_stacktrace_id("CommonType");

ast::ptr< ast::Type > handleReference(
	const ast::ptr< ast::Type > & t1, const ast::ptr< ast::Type > & t2, WidenMode widen,
	ast::TypeEnvironment & env,
	const ast::OpenVarSet & open
) {
	ast::ptr<ast::Type> common;
	ast::AssertionSet have, need;
	ast::OpenVarSet newOpen( open );

	// need unify to bind type variables
	if ( unify( t1, t2, env, have, need, newOpen, common ) ) {
		ast::CV::Qualifiers q1 = t1->qualifiers, q2 = t2->qualifiers;
		PRINT(
			std::cerr << "unify success: " << widenFirst << " " << widenSecond << std::endl;
		)
		if ( ( widen.first || q2 <= q1 ) && ( widen.second || q1 <= q2 ) ) {
			PRINT(
				std::cerr << "widen okay" << std::endl;
			)
			add_qualifiers( common, q1 | q2 );
			return common;
		}
	}

	PRINT(
		std::cerr << "exact unify failed: " << t1 << " " << t2 << std::endl;
	)
	return { nullptr };
}

} // namespace

ast::ptr< ast::Type > commonType(
	const ast::ptr< ast::Type > & type1, const ast::ptr< ast::Type > & type2,
	ast::TypeEnvironment & env, ast::AssertionSet & need, ast::AssertionSet & have,
	const ast::OpenVarSet & open, WidenMode widen
) {
	unsigned depth1 = type1->referenceDepth();
	unsigned depth2 = type2->referenceDepth();

	if ( depth1 != depth2 ) {  // implies depth1 > 0 || depth2 > 0
		PRINT(
			std::cerr << "reference depth diff: " << (depth1-depth2) << std::endl;
		)
		ast::ptr< ast::Type > result;
		const ast::ReferenceType * ref1 = type1.as< ast::ReferenceType >();
		const ast::ReferenceType * ref2 = type2.as< ast::ReferenceType >();

		if ( depth1 > depth2 ) {
			assert( ref1 );
			result = handleReference( ref1->base, type2, widen, env, open );
		} else {  // Implies depth1 < depth2
			assert( ref2 );
			result = handleReference( type1, ref2->base, widen, env, open );
		}

		if ( result && ref1 ) {
			// formal is reference, so result should be reference
			PRINT(
				std::cerr << "formal is reference; result should be reference" << std::endl;
			)
			result = new ast::ReferenceType{ result, ref1->qualifiers };
		}

		PRINT(
			std::cerr << "common type of reference [" << type1 << "] and [" << type2 << "] is "
			"[" << result << "]" << std::endl;
		)
		return result;
	}
	// otherwise both are reference types of the same depth and this is handled by the visitor
	return ast::Pass<CommonType>::read( type1.get(),
		type2, widen, env, open, need, have );
}

} // namespace ResolvExpr

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