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-rw-r--r--compiler/semfold.nim548
1 files changed, 306 insertions, 242 deletions
diff --git a/compiler/semfold.nim b/compiler/semfold.nim
index 604aa9fea..80144ccc0 100644
--- a/compiler/semfold.nim
+++ b/compiler/semfold.nim
@@ -11,22 +11,34 @@
 # and evaluation phase
 
 import
-  strutils, options, ast, trees, nimsets,
-  platform, math, msgs, idents, renderer, types,
-  commands, magicsys, modulegraphs, strtabs, lineinfos
+  options, ast, trees, nimsets,
+  platform, msgs, idents, renderer, types,
+  commands, magicsys, modulegraphs, lineinfos, wordrecg
+
+import std/[strutils, math, strtabs]
+from system/memory import nimCStrLen
+
+when defined(nimPreviewSlimSystem):
+  import std/[assertions, formatfloat]
 
 proc errorType*(g: ModuleGraph): PType =
   ## creates a type representing an error state
-  result = newType(tyError, g.owners[^1])
+  result = newType(tyError, g.idgen, g.owners[^1])
   result.flags.incl tfCheckedForDestructor
 
-proc newIntNodeT*(intVal: Int128, n: PNode; g: ModuleGraph): PNode =
+proc getIntLitTypeG(g: ModuleGraph; literal: PNode; idgen: IdGenerator): PType =
+  # we cache some common integer literal types for performance:
+  let ti = getSysType(g, literal.info, tyInt)
+  result = copyType(ti, idgen, ti.owner)
+  result.n = literal
+
+proc newIntNodeT*(intVal: Int128, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   result = newIntTypeNode(intVal, n.typ)
   # See bug #6989. 'pred' et al only produce an int literal type if the
   # original type was 'int', not a distinct int etc.
   if n.typ.kind == tyInt:
     # access cache for the int lit type
-    result.typ = getIntLitType(g, result)
+    result.typ = getIntLitTypeG(g, result, idgen)
   result.info = n.info
 
 proc newFloatNodeT*(floatVal: BiggestFloat, n: PNode; g: ModuleGraph): PNode =
@@ -42,36 +54,46 @@ proc newStrNodeT*(strVal: string, n: PNode; g: ModuleGraph): PNode =
   result.typ = n.typ
   result.info = n.info
 
-proc getConstExpr*(m: PSym, n: PNode; g: ModuleGraph): PNode
+proc getConstExpr*(m: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode
   # evaluates the constant expression or returns nil if it is no constant
   # expression
-proc evalOp*(m: TMagic, n, a, b, c: PNode; g: ModuleGraph): PNode
+proc evalOp*(m: TMagic, n, a, b, c: PNode; idgen: IdGenerator; g: ModuleGraph): PNode
 
 proc checkInRange(conf: ConfigRef; n: PNode, res: Int128): bool =
   res in firstOrd(conf, n.typ)..lastOrd(conf, n.typ)
 
-proc foldAdd(a, b: Int128, n: PNode; g: ModuleGraph): PNode =
+proc foldAdd(a, b: Int128, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   let res = a + b
   if checkInRange(g.config, n, res):
-    result = newIntNodeT(res, n, g)
+    result = newIntNodeT(res, n, idgen, g)
+  else:
+    result = nil
 
-proc foldSub(a, b: Int128, n: PNode; g: ModuleGraph): PNode =
+proc foldSub(a, b: Int128, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   let res = a - b
   if checkInRange(g.config, n, res):
-    result = newIntNodeT(res, n, g)
+    result = newIntNodeT(res, n, idgen, g)
+  else:
+    result = nil
 
-proc foldUnarySub(a: Int128, n: PNode, g: ModuleGraph): PNode =
+proc foldUnarySub(a: Int128, n: PNode; idgen: IdGenerator, g: ModuleGraph): PNode =
   if a != firstOrd(g.config, n.typ):
-    result = newIntNodeT(-a, n, g)
+    result = newIntNodeT(-a, n, idgen, g)
+  else:
+    result = nil
 
-proc foldAbs(a: Int128, n: PNode; g: ModuleGraph): PNode =
+proc foldAbs(a: Int128, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   if a != firstOrd(g.config, n.typ):
-    result = newIntNodeT(abs(a), n, g)
+    result = newIntNodeT(abs(a), n, idgen, g)
+  else:
+    result = nil
 
-proc foldMul(a, b: Int128, n: PNode; g: ModuleGraph): PNode =
+proc foldMul(a, b: Int128, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   let res = a * b
   if checkInRange(g.config, n, res):
-    return newIntNodeT(res, n, g)
+    return newIntNodeT(res, n, idgen, g)
+  else:
+    result = nil
 
 proc ordinalValToString*(a: PNode; g: ModuleGraph): string =
   # because $ has the param ordinal[T], `a` is not necessarily an enum, but an
@@ -83,6 +105,7 @@ proc ordinalValToString*(a: PNode; g: ModuleGraph): string =
   of tyChar:
     result = $chr(toInt64(x) and 0xff)
   of tyEnum:
+    result = ""
     var n = t.n
     for i in 0..<n.len:
       if n[i].kind != nkSym: internalError(g.config, a.info, "ordinalValToString")
@@ -99,10 +122,10 @@ proc ordinalValToString*(a: PNode; g: ModuleGraph): string =
     result = $x
 
 proc isFloatRange(t: PType): bool {.inline.} =
-  result = t.kind == tyRange and t[0].kind in {tyFloat..tyFloat128}
+  result = t.kind == tyRange and t.elementType.kind in {tyFloat..tyFloat128}
 
 proc isIntRange(t: PType): bool {.inline.} =
-  result = t.kind == tyRange and t[0].kind in {
+  result = t.kind == tyRange and t.elementType.kind in {
       tyInt..tyInt64, tyUInt8..tyUInt32}
 
 proc pickIntRange(a, b: PType): PType =
@@ -113,104 +136,68 @@ proc pickIntRange(a, b: PType): PType =
 proc isIntRangeOrLit(t: PType): bool =
   result = isIntRange(t) or isIntLit(t)
 
-proc makeRange(typ: PType, first, last: BiggestInt; g: ModuleGraph): PType =
-  let minA = min(first, last)
-  let maxA = max(first, last)
-  let lowerNode = newIntNode(nkIntLit, minA)
-  if typ.kind == tyInt and minA == maxA:
-    result = getIntLitType(g, lowerNode)
-  elif typ.kind in {tyUInt, tyUInt64}:
-    # these are not ordinal types, so you get no subrange type for these:
-    result = typ
-  else:
-    var n = newNode(nkRange)
-    n.add lowerNode
-    n.add newIntNode(nkIntLit, maxA)
-    result = newType(tyRange, typ.owner)
-    result.n = n
-    addSonSkipIntLit(result, skipTypes(typ, {tyRange}))
-
-proc makeRangeF(typ: PType, first, last: BiggestFloat; g: ModuleGraph): PType =
-  var n = newNode(nkRange)
-  n.add newFloatNode(nkFloatLit, min(first.float, last.float))
-  n.add newFloatNode(nkFloatLit, max(first.float, last.float))
-  result = newType(tyRange, typ.owner)
-  result.n = n
-  addSonSkipIntLit(result, skipTypes(typ, {tyRange}))
-
-proc fitLiteral(c: ConfigRef, n: PNode): PNode {.deprecated: "no substitute".} =
-  # Trim the literal value in order to make it fit in the destination type
-  if n == nil:
-    # `n` may be nil if the overflow check kicks in
-    return
-
-  doAssert n.kind in {nkIntLit, nkCharLit}
-
-  result = n
-
-  let typ = n.typ.skipTypes(abstractRange)
-  if typ.kind in tyUInt..tyUInt32:
-    result.intVal = result.intVal and castToInt64(lastOrd(c, typ))
-
-proc evalOp(m: TMagic, n, a, b, c: PNode; g: ModuleGraph): PNode =
+proc evalOp(m: TMagic, n, a, b, c: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   # b and c may be nil
   result = nil
   case m
-  of mOrd: result = newIntNodeT(getOrdValue(a), n, g)
-  of mChr: result = newIntNodeT(getInt(a), n, g)
-  of mUnaryMinusI, mUnaryMinusI64: result = foldUnarySub(getInt(a), n, g)
+  of mOrd: result = newIntNodeT(getOrdValue(a), n, idgen, g)
+  of mChr: result = newIntNodeT(getInt(a), n, idgen, g)
+  of mUnaryMinusI, mUnaryMinusI64: result = foldUnarySub(getInt(a), n, idgen, g)
   of mUnaryMinusF64: result = newFloatNodeT(-getFloat(a), n, g)
-  of mNot: result = newIntNodeT(One - getInt(a), n, g)
-  of mCard: result = newIntNodeT(toInt128(nimsets.cardSet(g.config, a)), n, g)
+  of mNot: result = newIntNodeT(One - getInt(a), n, idgen, g)
+  of mCard: result = newIntNodeT(toInt128(nimsets.cardSet(g.config, a)), n, idgen, g)
   of mBitnotI:
     if n.typ.isUnsigned:
-      result = newIntNodeT(bitnot(getInt(a)).maskBytes(int(n.typ.size)), n, g)
+      result = newIntNodeT(bitnot(getInt(a)).maskBytes(int(getSize(g.config, n.typ))), n, idgen, g)
     else:
-      result = newIntNodeT(bitnot(getInt(a)), n, g)
-  of mLengthArray: result = newIntNodeT(lengthOrd(g.config, a.typ), n, g)
+      result = newIntNodeT(bitnot(getInt(a)), n, idgen, g)
+  of mLengthArray: result = newIntNodeT(lengthOrd(g.config, a.typ), n, idgen, g)
   of mLengthSeq, mLengthOpenArray, mLengthStr:
     if a.kind == nkNilLit:
-      result = newIntNodeT(Zero, n, g)
+      result = newIntNodeT(Zero, n, idgen, g)
     elif a.kind in {nkStrLit..nkTripleStrLit}:
-      result = newIntNodeT(toInt128(a.strVal.len), n, g)
+      if a.typ.kind == tyString:
+        result = newIntNodeT(toInt128(a.strVal.len), n, idgen, g)
+      elif a.typ.kind == tyCstring:
+        result = newIntNodeT(toInt128(nimCStrLen(a.strVal.cstring)), n, idgen, g)
     else:
-      result = newIntNodeT(toInt128(a.len), n, g)
+      result = newIntNodeT(toInt128(a.len), n, idgen, g)
   of mUnaryPlusI, mUnaryPlusF64: result = a # throw `+` away
   # XXX: Hides overflow/underflow
-  of mAbsI: result = foldAbs(getInt(a), n, g)
-  of mSucc: result = foldAdd(getOrdValue(a), getInt(b), n, g)
-  of mPred: result = foldSub(getOrdValue(a), getInt(b), n, g)
-  of mAddI: result = foldAdd(getInt(a), getInt(b), n, g)
-  of mSubI: result = foldSub(getInt(a), getInt(b), n, g)
-  of mMulI: result = foldMul(getInt(a), getInt(b), n, g)
+  of mAbsI: result = foldAbs(getInt(a), n, idgen, g)
+  of mSucc: result = foldAdd(getOrdValue(a), getInt(b), n, idgen, g)
+  of mPred: result = foldSub(getOrdValue(a), getInt(b), n, idgen, g)
+  of mAddI: result = foldAdd(getInt(a), getInt(b), n, idgen, g)
+  of mSubI: result = foldSub(getInt(a), getInt(b), n, idgen, g)
+  of mMulI: result = foldMul(getInt(a), getInt(b), n, idgen, g)
   of mMinI:
     let argA = getInt(a)
     let argB = getInt(b)
-    result = newIntNodeT(if argA < argB: argA else: argB, n, g)
+    result = newIntNodeT(if argA < argB: argA else: argB, n, idgen, g)
   of mMaxI:
     let argA = getInt(a)
     let argB = getInt(b)
-    result = newIntNodeT(if argA > argB: argA else: argB, n, g)
+    result = newIntNodeT(if argA > argB: argA else: argB, n, idgen, g)
   of mShlI:
     case skipTypes(n.typ, abstractRange).kind
-    of tyInt8: result = newIntNodeT(toInt128(toInt8(getInt(a)) shl toInt64(getInt(b))), n, g)
-    of tyInt16: result = newIntNodeT(toInt128(toInt16(getInt(a)) shl toInt64(getInt(b))), n, g)
-    of tyInt32: result = newIntNodeT(toInt128(toInt32(getInt(a)) shl toInt64(getInt(b))), n, g)
-    of tyInt64: result = newIntNodeT(toInt128(toInt64(getInt(a)) shl toInt64(getInt(b))), n, g)
+    of tyInt8: result = newIntNodeT(toInt128(toInt8(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
+    of tyInt16: result = newIntNodeT(toInt128(toInt16(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
+    of tyInt32: result = newIntNodeT(toInt128(toInt32(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
+    of tyInt64: result = newIntNodeT(toInt128(toInt64(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
     of tyInt:
       if g.config.target.intSize == 4:
-        result = newIntNodeT(toInt128(toInt32(getInt(a)) shl toInt64(getInt(b))), n, g)
+        result = newIntNodeT(toInt128(toInt32(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
       else:
-        result = newIntNodeT(toInt128(toInt64(getInt(a)) shl toInt64(getInt(b))), n, g)
-    of tyUInt8: result = newIntNodeT(toInt128(toUInt8(getInt(a)) shl toInt64(getInt(b))), n, g)
-    of tyUInt16: result = newIntNodeT(toInt128(toUInt16(getInt(a)) shl toInt64(getInt(b))), n, g)
-    of tyUInt32: result = newIntNodeT(toInt128(toUInt32(getInt(a)) shl toInt64(getInt(b))), n, g)
-    of tyUInt64: result = newIntNodeT(toInt128(toUInt64(getInt(a)) shl toInt64(getInt(b))), n, g)
+        result = newIntNodeT(toInt128(toInt64(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
+    of tyUInt8: result = newIntNodeT(toInt128(toUInt8(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
+    of tyUInt16: result = newIntNodeT(toInt128(toUInt16(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
+    of tyUInt32: result = newIntNodeT(toInt128(toUInt32(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
+    of tyUInt64: result = newIntNodeT(toInt128(toUInt64(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
     of tyUInt:
       if g.config.target.intSize == 4:
-        result = newIntNodeT(toInt128(toUInt32(getInt(a)) shl toInt64(getInt(b))), n, g)
+        result = newIntNodeT(toInt128(toUInt32(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
       else:
-        result = newIntNodeT(toInt128(toUInt64(getInt(a)) shl toInt64(getInt(b))), n, g)
+        result = newIntNodeT(toInt128(toUInt64(getInt(a)) shl toInt64(getInt(b))), n, idgen, g)
     else: internalError(g.config, n.info, "constant folding for shl")
   of mShrI:
     var a = cast[uint64](getInt(a))
@@ -231,75 +218,81 @@ proc evalOp(m: TMagic, n, a, b, c: PNode; g: ModuleGraph): PNode =
         # unsigned and 64 bit integers don't need masking
         discard
     let c = cast[BiggestInt](a shr b)
-    result = newIntNodeT(toInt128(c), n, g)
+    result = newIntNodeT(toInt128(c), n, idgen, g)
   of mAshrI:
     case skipTypes(n.typ, abstractRange).kind
-    of tyInt8: result =  newIntNodeT(toInt128(ashr(toInt8(getInt(a)), toInt8(getInt(b)))), n, g)
-    of tyInt16: result = newIntNodeT(toInt128(ashr(toInt16(getInt(a)), toInt16(getInt(b)))), n, g)
-    of tyInt32: result = newIntNodeT(toInt128(ashr(toInt32(getInt(a)), toInt32(getInt(b)))), n, g)
+    of tyInt8: result =  newIntNodeT(toInt128(ashr(toInt8(getInt(a)), toInt8(getInt(b)))), n, idgen, g)
+    of tyInt16: result = newIntNodeT(toInt128(ashr(toInt16(getInt(a)), toInt16(getInt(b)))), n, idgen, g)
+    of tyInt32: result = newIntNodeT(toInt128(ashr(toInt32(getInt(a)), toInt32(getInt(b)))), n, idgen, g)
     of tyInt64, tyInt:
-      result = newIntNodeT(toInt128(ashr(toInt64(getInt(a)), toInt64(getInt(b)))), n, g)
+      result = newIntNodeT(toInt128(ashr(toInt64(getInt(a)), toInt64(getInt(b)))), n, idgen, g)
     else: internalError(g.config, n.info, "constant folding for ashr")
   of mDivI:
     let argA = getInt(a)
     let argB = getInt(b)
     if argB != Zero and (argA != firstOrd(g.config, n.typ) or argB != NegOne):
-      result = newIntNodeT(argA div argB, n, g)
+      result = newIntNodeT(argA div argB, n, idgen, g)
   of mModI:
     let argA = getInt(a)
     let argB = getInt(b)
     if argB != Zero and (argA != firstOrd(g.config, n.typ) or argB != NegOne):
-      result = newIntNodeT(argA mod argB, n, g)
+      result = newIntNodeT(argA mod argB, n, idgen, g)
   of mAddF64: result = newFloatNodeT(getFloat(a) + getFloat(b), n, g)
   of mSubF64: result = newFloatNodeT(getFloat(a) - getFloat(b), n, g)
   of mMulF64: result = newFloatNodeT(getFloat(a) * getFloat(b), n, g)
   of mDivF64:
     result = newFloatNodeT(getFloat(a) / getFloat(b), n, g)
-  of mIsNil: result = newIntNodeT(toInt128(ord(a.kind == nkNilLit)), n, g)
+  of mIsNil:
+    let val = a.kind == nkNilLit or
+      # nil closures have the value (nil, nil)
+      (a.typ != nil and skipTypes(a.typ, abstractRange).kind == tyProc and
+        a.kind == nkTupleConstr and a.len == 2 and
+        a[0].kind == nkNilLit and a[1].kind == nkNilLit)
+    result = newIntNodeT(toInt128(ord(val)), n, idgen, g)
   of mLtI, mLtB, mLtEnum, mLtCh:
-    result = newIntNodeT(toInt128(ord(getOrdValue(a) < getOrdValue(b))), n, g)
+    result = newIntNodeT(toInt128(ord(getOrdValue(a) < getOrdValue(b))), n, idgen, g)
   of mLeI, mLeB, mLeEnum, mLeCh:
-    result = newIntNodeT(toInt128(ord(getOrdValue(a) <= getOrdValue(b))), n, g)
+    result = newIntNodeT(toInt128(ord(getOrdValue(a) <= getOrdValue(b))), n, idgen, g)
   of mEqI, mEqB, mEqEnum, mEqCh:
-    result = newIntNodeT(toInt128(ord(getOrdValue(a) == getOrdValue(b))), n, g)
-  of mLtF64: result = newIntNodeT(toInt128(ord(getFloat(a) < getFloat(b))), n, g)
-  of mLeF64: result = newIntNodeT(toInt128(ord(getFloat(a) <= getFloat(b))), n, g)
-  of mEqF64: result = newIntNodeT(toInt128(ord(getFloat(a) == getFloat(b))), n, g)
-  of mLtStr: result = newIntNodeT(toInt128(ord(getStr(a) < getStr(b))), n, g)
-  of mLeStr: result = newIntNodeT(toInt128(ord(getStr(a) <= getStr(b))), n, g)
-  of mEqStr: result = newIntNodeT(toInt128(ord(getStr(a) == getStr(b))), n, g)
+    result = newIntNodeT(toInt128(ord(getOrdValue(a) == getOrdValue(b))), n, idgen, g)
+  of mLtF64: result = newIntNodeT(toInt128(ord(getFloat(a) < getFloat(b))), n, idgen, g)
+  of mLeF64: result = newIntNodeT(toInt128(ord(getFloat(a) <= getFloat(b))), n, idgen, g)
+  of mEqF64: result = newIntNodeT(toInt128(ord(getFloat(a) == getFloat(b))), n, idgen, g)
+  of mLtStr: result = newIntNodeT(toInt128(ord(getStr(a) < getStr(b))), n, idgen, g)
+  of mLeStr: result = newIntNodeT(toInt128(ord(getStr(a) <= getStr(b))), n, idgen, g)
+  of mEqStr: result = newIntNodeT(toInt128(ord(getStr(a) == getStr(b))), n, idgen, g)
   of mLtU:
-    result = newIntNodeT(toInt128(ord(`<%`(toInt64(getOrdValue(a)), toInt64(getOrdValue(b))))), n, g)
+    result = newIntNodeT(toInt128(ord(`<%`(toInt64(getOrdValue(a)), toInt64(getOrdValue(b))))), n, idgen, g)
   of mLeU:
-    result = newIntNodeT(toInt128(ord(`<=%`(toInt64(getOrdValue(a)), toInt64(getOrdValue(b))))), n, g)
-  of mBitandI, mAnd: result = newIntNodeT(bitand(a.getInt, b.getInt), n, g)
-  of mBitorI, mOr: result = newIntNodeT(bitor(getInt(a), getInt(b)), n, g)
-  of mBitxorI, mXor: result = newIntNodeT(bitxor(getInt(a), getInt(b)), n, g)
+    result = newIntNodeT(toInt128(ord(`<=%`(toInt64(getOrdValue(a)), toInt64(getOrdValue(b))))), n, idgen, g)
+  of mBitandI, mAnd: result = newIntNodeT(bitand(a.getInt, b.getInt), n, idgen, g)
+  of mBitorI, mOr: result = newIntNodeT(bitor(getInt(a), getInt(b)), n, idgen, g)
+  of mBitxorI, mXor: result = newIntNodeT(bitxor(getInt(a), getInt(b)), n, idgen, g)
   of mAddU:
-    let val = maskBytes(getInt(a) + getInt(b), int(n.typ.size))
-    result = newIntNodeT(val, n, g)
+    let val = maskBytes(getInt(a) + getInt(b), int(getSize(g.config, n.typ)))
+    result = newIntNodeT(val, n, idgen, g)
   of mSubU:
-    let val = maskBytes(getInt(a) - getInt(b), int(n.typ.size))
-    result = newIntNodeT(val, n, g)
+    let val = maskBytes(getInt(a) - getInt(b), int(getSize(g.config, n.typ)))
+    result = newIntNodeT(val, n, idgen, g)
     # echo "subU: ", val, " n: ", n, " result: ", val
   of mMulU:
-    let val = maskBytes(getInt(a) * getInt(b), int(n.typ.size))
-    result = newIntNodeT(val, n, g)
+    let val = maskBytes(getInt(a) * getInt(b), int(getSize(g.config, n.typ)))
+    result = newIntNodeT(val, n, idgen, g)
   of mModU:
-    let argA = maskBytes(getInt(a), int(a.typ.size))
-    let argB = maskBytes(getInt(b), int(a.typ.size))
+    let argA = maskBytes(getInt(a), int(getSize(g.config, a.typ)))
+    let argB = maskBytes(getInt(b), int(getSize(g.config, a.typ)))
     if argB != Zero:
-      result = newIntNodeT(argA mod argB, n, g)
+      result = newIntNodeT(argA mod argB, n, idgen, g)
   of mDivU:
-    let argA = maskBytes(getInt(a), int(a.typ.size))
-    let argB = maskBytes(getInt(b), int(a.typ.size))
+    let argA = maskBytes(getInt(a), int(getSize(g.config, a.typ)))
+    let argB = maskBytes(getInt(b), int(getSize(g.config, a.typ)))
     if argB != Zero:
-      result = newIntNodeT(argA div argB, n, g)
-  of mLeSet: result = newIntNodeT(toInt128(ord(containsSets(g.config, a, b))), n, g)
-  of mEqSet: result = newIntNodeT(toInt128(ord(equalSets(g.config, a, b))), n, g)
+      result = newIntNodeT(argA div argB, n, idgen, g)
+  of mLeSet: result = newIntNodeT(toInt128(ord(containsSets(g.config, a, b))), n, idgen, g)
+  of mEqSet: result = newIntNodeT(toInt128(ord(equalSets(g.config, a, b))), n, idgen, g)
   of mLtSet:
     result = newIntNodeT(toInt128(ord(
-      containsSets(g.config, a, b) and not equalSets(g.config, a, b))), n, g)
+      containsSets(g.config, a, b) and not equalSets(g.config, a, b))), n, idgen, g)
   of mMulSet:
     result = nimsets.intersectSets(g.config, a, b)
     result.info = n.info
@@ -310,51 +303,43 @@ proc evalOp(m: TMagic, n, a, b, c: PNode; g: ModuleGraph): PNode =
     result = nimsets.diffSets(g.config, a, b)
     result.info = n.info
   of mConStrStr: result = newStrNodeT(getStrOrChar(a) & getStrOrChar(b), n, g)
-  of mInSet: result = newIntNodeT(toInt128(ord(inSet(a, b))), n, g)
+  of mInSet: result = newIntNodeT(toInt128(ord(inSet(a, b))), n, idgen, g)
   of mRepr:
     # BUGFIX: we cannot eval mRepr here for reasons that I forgot.
     discard
-  of mIntToStr, mInt64ToStr: result = newStrNodeT($(getOrdValue(a)), n, g)
   of mBoolToStr:
     if getOrdValue(a) == 0: result = newStrNodeT("false", n, g)
     else: result = newStrNodeT("true", n, g)
-  of mFloatToStr: result = newStrNodeT($getFloat(a), n, g)
   of mCStrToStr, mCharToStr:
-    if a.kind == nkBracket:
-      var s = ""
-      for b in a.sons:
-        s.add b.getStrOrChar
-      result = newStrNodeT(s, n, g)
-    else:
-      result = newStrNodeT(getStrOrChar(a), n, g)
+    result = newStrNodeT(getStrOrChar(a), n, g)
   of mStrToStr: result = newStrNodeT(getStrOrChar(a), n, g)
   of mEnumToStr: result = newStrNodeT(ordinalValToString(a, g), n, g)
   of mArrToSeq:
     result = copyTree(a)
     result.typ = n.typ
   of mCompileOption:
-    result = newIntNodeT(toInt128(ord(commands.testCompileOption(g.config, a.getStr, n.info))), n, g)
+    result = newIntNodeT(toInt128(ord(commands.testCompileOption(g.config, a.getStr, n.info))), n, idgen, g)
   of mCompileOptionArg:
     result = newIntNodeT(toInt128(ord(
-      testCompileOptionArg(g.config, getStr(a), getStr(b), n.info))), n, g)
+      testCompileOptionArg(g.config, getStr(a), getStr(b), n.info))), n, idgen, g)
   of mEqProc:
     result = newIntNodeT(toInt128(ord(
-        exprStructuralEquivalent(a, b, strictSymEquality=true))), n, g)
+        exprStructuralEquivalent(a, b, strictSymEquality=true))), n, idgen, g)
   else: discard
 
-proc getConstIfExpr(c: PSym, n: PNode; g: ModuleGraph): PNode =
+proc getConstIfExpr(c: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   result = nil
   for i in 0..<n.len:
     var it = n[i]
     if it.len == 2:
-      var e = getConstExpr(c, it[0], g)
+      var e = getConstExpr(c, it[0], idgen, g)
       if e == nil: return nil
       if getOrdValue(e) != 0:
         if result == nil:
-          result = getConstExpr(c, it[1], g)
+          result = getConstExpr(c, it[1], idgen, g)
           if result == nil: return
     elif it.len == 1:
-      if result == nil: result = getConstExpr(c, it[0], g)
+      if result == nil: result = getConstExpr(c, it[0], idgen, g)
     else: internalError(g.config, it.info, "getConstIfExpr()")
 
 proc leValueConv*(a, b: PNode): bool =
@@ -372,20 +357,20 @@ proc leValueConv*(a, b: PNode): bool =
     else: result = false # internalError(a.info, "leValueConv")
   else: result = false # internalError(a.info, "leValueConv")
 
-proc magicCall(m: PSym, n: PNode; g: ModuleGraph): PNode =
+proc magicCall(m: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   if n.len <= 1: return
 
   var s = n[0].sym
-  var a = getConstExpr(m, n[1], g)
-  var b, c: PNode
+  var a = getConstExpr(m, n[1], idgen, g)
+  var b, c: PNode = nil
   if a == nil: return
   if n.len > 2:
-    b = getConstExpr(m, n[2], g)
+    b = getConstExpr(m, n[2], idgen, g)
     if b == nil: return
     if n.len > 3:
-      c = getConstExpr(m, n[3], g)
+      c = getConstExpr(m, n[3], idgen, g)
       if c == nil: return
-  result = evalOp(s.magic, n, a, b, c, g)
+  result = evalOp(s.magic, n, a, b, c, idgen, g)
 
 proc getAppType(n: PNode; g: ModuleGraph): PNode =
   if g.config.globalOptions.contains(optGenDynLib):
@@ -402,7 +387,12 @@ proc rangeCheck(n: PNode, value: Int128; g: ModuleGraph) =
     localError(g.config, n.info, "cannot convert " & $value &
                                     " to " & typeToString(n.typ))
 
-proc foldConv(n, a: PNode; g: ModuleGraph; check = false): PNode =
+proc floatRangeCheck(n: PNode, value: BiggestFloat; g: ModuleGraph) =
+  if value < firstFloat(n.typ) or value > lastFloat(n.typ):
+    localError(g.config, n.info, "cannot convert " & $value &
+                                    " to " & typeToString(n.typ))
+
+proc foldConv(n, a: PNode; idgen: IdGenerator; g: ModuleGraph; check = false): PNode =
   let dstTyp = skipTypes(n.typ, abstractRange - {tyTypeDesc})
   let srcTyp = skipTypes(a.typ, abstractRange - {tyTypeDesc})
 
@@ -416,54 +406,58 @@ proc foldConv(n, a: PNode; g: ModuleGraph; check = false): PNode =
   of tyBool:
     case srcTyp.kind
     of tyFloat..tyFloat64:
-      result = newIntNodeT(toInt128(getFloat(a) != 0.0), n, g)
+      result = newIntNodeT(toInt128(getFloat(a) != 0.0), n, idgen, g)
     of tyChar, tyUInt..tyUInt64, tyInt..tyInt64:
-      result = newIntNodeT(toInt128(a.getOrdValue != 0), n, g)
+      result = newIntNodeT(toInt128(a.getOrdValue != 0), n, idgen, g)
     of tyBool, tyEnum: # xxx shouldn't we disallow `tyEnum`?
       result = a
       result.typ = n.typ
-    else: doAssert false, $srcTyp.kind
+    else:
+      raiseAssert $srcTyp.kind
   of tyInt..tyInt64, tyUInt..tyUInt64:
     case srcTyp.kind
     of tyFloat..tyFloat64:
-      result = newIntNodeT(toInt128(getFloat(a)), n, g)
+      result = newIntNodeT(toInt128(getFloat(a)), n, idgen, g)
     of tyChar, tyUInt..tyUInt64, tyInt..tyInt64:
       var val = a.getOrdValue
-      if check: rangeCheck(n, val, g)
-      result = newIntNodeT(val, n, g)
       if dstTyp.kind in {tyUInt..tyUInt64}:
+        result = newIntNodeT(maskBytes(val, int getSize(g.config, dstTyp)), n, idgen, g)
         result.transitionIntKind(nkUIntLit)
+      else:
+        if check: rangeCheck(n, val, g)
+        result = newIntNodeT(val, n, idgen, g)
     else:
       result = a
       result.typ = n.typ
-    if check and result.kind in {nkCharLit..nkUInt64Lit}:
+    if check and result.kind in {nkCharLit..nkUInt64Lit} and
+          dstTyp.kind notin {tyUInt..tyUInt64}:
       rangeCheck(n, getInt(result), g)
   of tyFloat..tyFloat64:
     case srcTyp.kind
-    of tyInt..tyInt64, tyEnum, tyBool, tyChar:
+    of tyInt..tyInt64, tyUInt..tyUInt64, tyEnum, tyBool, tyChar:
       result = newFloatNodeT(toFloat64(getOrdValue(a)), n, g)
     else:
       result = a
       result.typ = n.typ
   of tyOpenArray, tyVarargs, tyProc, tyPointer:
-    discard
+    result = nil
   else:
     result = a
     result.typ = n.typ
 
-proc getArrayConstr(m: PSym, n: PNode; g: ModuleGraph): PNode =
+proc getArrayConstr(m: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   if n.kind == nkBracket:
     result = n
   else:
-    result = getConstExpr(m, n, g)
+    result = getConstExpr(m, n, idgen, g)
     if result == nil: result = n
 
-proc foldArrayAccess(m: PSym, n: PNode; g: ModuleGraph): PNode =
-  var x = getConstExpr(m, n[0], g)
+proc foldArrayAccess(m: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
+  var x = getConstExpr(m, n[0], idgen, g)
   if x == nil or x.typ.skipTypes({tyGenericInst, tyAlias, tySink}).kind == tyTypeDesc:
     return
 
-  var y = getConstExpr(m, n[1], g)
+  var y = getConstExpr(m, n[1], idgen, g)
   if y == nil: return
 
   var idx = toInt64(getOrdValue(y))
@@ -473,22 +467,27 @@ proc foldArrayAccess(m: PSym, n: PNode; g: ModuleGraph): PNode =
       result = x.sons[idx]
       if result.kind == nkExprColonExpr: result = result[1]
     else:
+      result = nil
       localError(g.config, n.info, formatErrorIndexBound(idx, x.len-1) & $n)
   of nkBracket:
-    idx = idx - toInt64(firstOrd(g.config, x.typ))
+    idx -= toInt64(firstOrd(g.config, x.typ))
     if idx >= 0 and idx < x.len: result = x[int(idx)]
-    else: localError(g.config, n.info, formatErrorIndexBound(idx, x.len-1) & $n)
+    else:
+      result = nil
+      localError(g.config, n.info, formatErrorIndexBound(idx, x.len-1) & $n)
   of nkStrLit..nkTripleStrLit:
     result = newNodeIT(nkCharLit, x.info, n.typ)
     if idx >= 0 and idx < x.strVal.len:
       result.intVal = ord(x.strVal[int(idx)])
     else:
       localError(g.config, n.info, formatErrorIndexBound(idx, x.strVal.len-1) & $n)
-  else: discard
+  else: result = nil
 
-proc foldFieldAccess(m: PSym, n: PNode; g: ModuleGraph): PNode =
+proc foldFieldAccess(m: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   # a real field access; proc calls have already been transformed
-  var x = getConstExpr(m, n[0], g)
+  result = nil
+  if n[1].kind != nkSym: return nil
+  var x = getConstExpr(m, n[0], idgen, g)
   if x == nil or x.kind notin {nkObjConstr, nkPar, nkTupleConstr}: return
 
   var field = n[1].sym
@@ -504,78 +503,135 @@ proc foldFieldAccess(m: PSym, n: PNode; g: ModuleGraph): PNode =
       return
   localError(g.config, n.info, "field not found: " & field.name.s)
 
-proc foldConStrStr(m: PSym, n: PNode; g: ModuleGraph): PNode =
+proc foldConStrStr(m: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   result = newNodeIT(nkStrLit, n.info, n.typ)
   result.strVal = ""
   for i in 1..<n.len:
-    let a = getConstExpr(m, n[i], g)
+    let a = getConstExpr(m, n[i], idgen, g)
     if a == nil: return nil
     result.strVal.add(getStrOrChar(a))
 
-proc newSymNodeTypeDesc*(s: PSym; info: TLineInfo): PNode =
+proc newSymNodeTypeDesc*(s: PSym; idgen: IdGenerator; info: TLineInfo): PNode =
   result = newSymNode(s, info)
   if s.typ.kind != tyTypeDesc:
-    result.typ = newType(tyTypeDesc, s.owner)
-    result.typ.addSonSkipIntLit(s.typ)
+    result.typ = newType(tyTypeDesc, idgen, s.owner)
+    result.typ.addSonSkipIntLit(s.typ, idgen)
   else:
     result.typ = s.typ
 
-proc getConstExpr(m: PSym, n: PNode; g: ModuleGraph): PNode =
+proc foldDefine(m, s: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
+  result = nil
+  var name = s.name.s
+  let prag = extractPragma(s)
+  if prag != nil:
+    for it in prag:
+      if it.kind in nkPragmaCallKinds and it.len == 2 and it[0].kind == nkIdent:
+        let word = whichKeyword(it[0].ident)
+        if word in {wStrDefine, wIntDefine, wBoolDefine, wDefine}:
+          # should be processed in pragmas.nim already
+          if it[1].kind in {nkStrLit, nkRStrLit, nkTripleStrLit}:
+            name = it[1].strVal
+  if isDefined(g.config, name):
+    let str = g.config.symbols[name]
+    case s.magic
+    of mIntDefine:
+      try:
+        result = newIntNodeT(toInt128(str.parseInt), n, idgen, g)
+      except ValueError:
+        localError(g.config, s.info,
+          "{.intdefine.} const was set to an invalid integer: '" &
+            str & "'")
+    of mStrDefine:
+      result = newStrNodeT(str, n, g)
+    of mBoolDefine:
+      try:
+        result = newIntNodeT(toInt128(str.parseBool.int), n, idgen, g)
+      except ValueError:
+        localError(g.config, s.info,
+          "{.booldefine.} const was set to an invalid bool: '" &
+            str & "'")
+    of mGenericDefine:
+      let rawTyp = s.typ
+      # pretend we don't support distinct types
+      let typ = rawTyp.skipTypes(abstractVarRange-{tyDistinct})
+      try:
+        template intNode(value): PNode =
+          let val = toInt128(value)
+          rangeCheck(n, val, g)
+          newIntNodeT(val, n, idgen, g)
+        case typ.kind
+        of tyString, tyCstring:
+          result = newStrNodeT(str, n, g)
+        of tyInt..tyInt64:
+          result = intNode(str.parseBiggestInt)
+        of tyUInt..tyUInt64:
+          result = intNode(str.parseBiggestUInt)
+        of tyBool:
+          result = intNode(str.parseBool.int)
+        of tyEnum:
+          # compile time parseEnum
+          let ident = getIdent(g.cache, str)
+          for e in typ.n:
+            if e.kind != nkSym: internalError(g.config, "foldDefine for enum")
+            let es = e.sym
+            let match =
+              if es.ast.isNil:
+                es.name.id == ident.id
+              else:
+                es.ast.strVal == str
+            if match:
+              result = intNode(es.position)
+              break
+          if result.isNil:
+            raise newException(ValueError, "invalid enum value: " & str)
+        else:
+          localError(g.config, s.info, "unsupported type $1 for define '$2'" %
+            [name, typeToString(rawTyp)])
+      except ValueError as e:
+        localError(g.config, s.info,
+          "could not process define '$1' of type $2; $3" %
+            [name, typeToString(rawTyp), e.msg])
+    else: result = copyTree(s.astdef) # unreachable
+  else:
+    result = copyTree(s.astdef)
+    if result != nil:
+      result.info = n.info
+
+proc getConstExpr(m: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode =
   result = nil
   case n.kind
   of nkSym:
     var s = n.sym
     case s.kind
     of skEnumField:
-      result = newIntNodeT(toInt128(s.position), n, g)
+      result = newIntNodeT(toInt128(s.position), n, idgen, g)
     of skConst:
       case s.magic
-      of mIsMainModule: result = newIntNodeT(toInt128(ord(sfMainModule in m.flags)), n, g)
+      of mIsMainModule: result = newIntNodeT(toInt128(ord(sfMainModule in m.flags)), n, idgen, g)
       of mCompileDate: result = newStrNodeT(getDateStr(), n, g)
       of mCompileTime: result = newStrNodeT(getClockStr(), n, g)
-      of mCpuEndian: result = newIntNodeT(toInt128(ord(CPU[g.config.target.targetCPU].endian)), n, g)
+      of mCpuEndian: result = newIntNodeT(toInt128(ord(CPU[g.config.target.targetCPU].endian)), n, idgen, g)
       of mHostOS: result = newStrNodeT(toLowerAscii(platform.OS[g.config.target.targetOS].name), n, g)
       of mHostCPU: result = newStrNodeT(platform.CPU[g.config.target.targetCPU].name.toLowerAscii, n, g)
       of mBuildOS: result = newStrNodeT(toLowerAscii(platform.OS[g.config.target.hostOS].name), n, g)
       of mBuildCPU: result = newStrNodeT(platform.CPU[g.config.target.hostCPU].name.toLowerAscii, n, g)
       of mAppType: result = getAppType(n, g)
-      of mIntDefine:
-        if isDefined(g.config, s.name.s):
-          try:
-            result = newIntNodeT(toInt128(g.config.symbols[s.name.s].parseInt), n, g)
-          except ValueError:
-            localError(g.config, s.info,
-              "{.intdefine.} const was set to an invalid integer: '" &
-                g.config.symbols[s.name.s] & "'")
-        else:
-          result = copyTree(s.ast)
-      of mStrDefine:
-        if isDefined(g.config, s.name.s):
-          result = newStrNodeT(g.config.symbols[s.name.s], n, g)
-        else:
-          result = copyTree(s.ast)
-      of mBoolDefine:
-        if isDefined(g.config, s.name.s):
-          try:
-            result = newIntNodeT(toInt128(g.config.symbols[s.name.s].parseBool.int), n, g)
-          except ValueError:
-            localError(g.config, s.info,
-              "{.booldefine.} const was set to an invalid bool: '" &
-                g.config.symbols[s.name.s] & "'")
-        else:
-          result = copyTree(s.ast)
+      of mIntDefine, mStrDefine, mBoolDefine, mGenericDefine:
+        result = foldDefine(m, s, n, idgen, g)
       else:
-        result = copyTree(s.ast)
+        result = copyTree(s.astdef)
+        if result != nil:
+          result.info = n.info
     of skProc, skFunc, skMethod:
       result = n
     of skParam:
       if s.typ != nil and s.typ.kind == tyTypeDesc:
-        result = newSymNodeTypeDesc(s, n.info)
+        result = newSymNodeTypeDesc(s, idgen, n.info)
     of skType:
       # XXX gensym'ed symbols can come here and cannot be resolved. This is
       # dirty, but correct.
       if s.typ != nil:
-        result = newSymNodeTypeDesc(s, n.info)
+        result = newSymNodeTypeDesc(s, idgen, n.info)
     of skGenericParam:
       if s.typ.kind == tyStatic:
         if s.typ.n != nil and tfUnresolved notin s.typ.flags:
@@ -584,12 +640,12 @@ proc getConstExpr(m: PSym, n: PNode; g: ModuleGraph): PNode =
       elif s.typ.isIntLit:
         result = s.typ.n
       else:
-        result = newSymNodeTypeDesc(s, n.info)
+        result = newSymNodeTypeDesc(s, idgen, n.info)
     else: discard
   of nkCharLit..nkNilLit:
     result = copyNode(n)
   of nkIfExpr:
-    result = getConstIfExpr(m, n, g)
+    result = getConstIfExpr(m, n, idgen, g)
   of nkCallKinds:
     if n[0].kind != nkSym: return
     var s = n[0].sym
@@ -603,30 +659,30 @@ proc getConstExpr(m: PSym, n: PNode; g: ModuleGraph): PNode =
         if skipTypes(n[1].typ, abstractVarRange).kind in tyFloat..tyFloat64:
           result = newFloatNodeT(firstFloat(n[1].typ), n, g)
         else:
-          result = newIntNodeT(firstOrd(g.config, n[1].typ), n, g)
+          result = newIntNodeT(firstOrd(g.config, n[1].typ), n, idgen, g)
       of mHigh:
         if skipTypes(n[1].typ, abstractVar+{tyUserTypeClassInst}).kind notin
-            {tySequence, tyString, tyCString, tyOpenArray, tyVarargs}:
+            {tySequence, tyString, tyCstring, tyOpenArray, tyVarargs}:
           if skipTypes(n[1].typ, abstractVarRange).kind in tyFloat..tyFloat64:
             result = newFloatNodeT(lastFloat(n[1].typ), n, g)
           else:
-            result = newIntNodeT(lastOrd(g.config, skipTypes(n[1].typ, abstractVar)), n, g)
+            result = newIntNodeT(lastOrd(g.config, skipTypes(n[1].typ, abstractVar)), n, idgen, g)
         else:
-          var a = getArrayConstr(m, n[1], g)
+          var a = getArrayConstr(m, n[1], idgen, g)
           if a.kind == nkBracket:
             # we can optimize it away:
-            result = newIntNodeT(toInt128(a.len-1), n, g)
+            result = newIntNodeT(toInt128(a.len-1), n, idgen, g)
       of mLengthOpenArray:
-        var a = getArrayConstr(m, n[1], g)
+        var a = getArrayConstr(m, n[1], idgen, g)
         if a.kind == nkBracket:
           # we can optimize it away! This fixes the bug ``len(134)``.
-          result = newIntNodeT(toInt128(a.len), n, g)
+          result = newIntNodeT(toInt128(a.len), n, idgen, g)
         else:
-          result = magicCall(m, n, g)
+          result = magicCall(m, n, idgen, g)
       of mLengthArray:
         # It doesn't matter if the argument is const or not for mLengthArray.
         # This fixes bug #544.
-        result = newIntNodeT(lengthOrd(g.config, n[1].typ), n, g)
+        result = newIntNodeT(lengthOrd(g.config, n[1].typ), n, idgen, g)
       of mSizeOf:
         result = foldSizeOf(g.config, n, nil)
       of mAlignOf:
@@ -636,33 +692,30 @@ proc getConstExpr(m: PSym, n: PNode; g: ModuleGraph): PNode =
       of mAstToStr:
         result = newStrNodeT(renderTree(n[1], {renderNoComments}), n, g)
       of mConStrStr:
-        result = foldConStrStr(m, n, g)
+        result = foldConStrStr(m, n, idgen, g)
       of mIs:
         # The only kind of mIs node that comes here is one depending on some
         # generic parameter and that's (hopefully) handled at instantiation time
         discard
       else:
-        result = magicCall(m, n, g)
+        result = magicCall(m, n, idgen, g)
     except OverflowDefect:
       localError(g.config, n.info, "over- or underflow")
     except DivByZeroDefect:
       localError(g.config, n.info, "division by zero")
   of nkAddr:
-    var a = getConstExpr(m, n[0], g)
-    if a != nil:
-      result = n
-      n[0] = a
+    result = nil # don't fold paths containing nkAddr
   of nkBracket, nkCurly:
     result = copyNode(n)
-    for i, son in n.pairs:
-      var a = getConstExpr(m, son, g)
+    for son in n.items:
+      var a = getConstExpr(m, son, idgen, g)
       if a == nil: return nil
       result.add a
     incl(result.flags, nfAllConst)
   of nkRange:
-    var a = getConstExpr(m, n[0], g)
+    var a = getConstExpr(m, n[0], idgen, g)
     if a == nil: return
-    var b = getConstExpr(m, n[1], g)
+    var b = getConstExpr(m, n[1], idgen, g)
     if b == nil: return
     result = copyNode(n)
     result.add a
@@ -678,53 +731,64 @@ proc getConstExpr(m: PSym, n: PNode; g: ModuleGraph): PNode =
     # tuple constructor
     result = copyNode(n)
     if (n.len > 0) and (n[0].kind == nkExprColonExpr):
-      for i, expr in n.pairs:
+      for expr in n.items:
         let exprNew = copyNode(expr) # nkExprColonExpr
         exprNew.add expr[0]
-        let a = getConstExpr(m, expr[1], g)
+        let a = getConstExpr(m, expr[1], idgen, g)
         if a == nil: return nil
         exprNew.add a
         result.add exprNew
     else:
-      for i, expr in n.pairs:
-        let a = getConstExpr(m, expr, g)
+      for expr in n.items:
+        let a = getConstExpr(m, expr, idgen, g)
         if a == nil: return nil
         result.add a
     incl(result.flags, nfAllConst)
   of nkChckRangeF, nkChckRange64, nkChckRange:
-    var a = getConstExpr(m, n[0], g)
+    var a = getConstExpr(m, n[0], idgen, g)
     if a == nil: return
     if leValueConv(n[1], a) and leValueConv(a, n[2]):
       result = a              # a <= x and x <= b
       result.typ = n.typ
+    elif n.typ.kind in {tyUInt..tyUInt64}:
+      discard "don't check uints"
     else:
       localError(g.config, n.info,
         "conversion from $1 to $2 is invalid" %
           [typeToString(n[0].typ), typeToString(n.typ)])
   of nkStringToCString, nkCStringToString:
-    var a = getConstExpr(m, n[0], g)
+    var a = getConstExpr(m, n[0], idgen, g)
     if a == nil: return
     result = a
     result.typ = n.typ
   of nkHiddenStdConv, nkHiddenSubConv, nkConv:
-    var a = getConstExpr(m, n[1], g)
+    var a = getConstExpr(m, n[1], idgen, g)
     if a == nil: return
-    result = foldConv(n, a, g, check=true)
+    result = foldConv(n, a, idgen, g, check=true)
+  of nkDerefExpr, nkHiddenDeref:
+    let a = getConstExpr(m, n[0], idgen, g)
+    if a != nil and a.kind == nkNilLit:
+      result = nil
+      #localError(g.config, n.info, "nil dereference is not allowed")
   of nkCast:
-    var a = getConstExpr(m, n[1], g)
+    var a = getConstExpr(m, n[1], idgen, g)
     if a == nil: return
-    if n.typ != nil and n.typ.kind in NilableTypes:
+    if n.typ != nil and n.typ.kind in NilableTypes and
+        not (n.typ.kind == tyProc and a.typ.kind == tyProc):
       # we allow compile-time 'cast' for pointer types:
       result = a
       result.typ = n.typ
-  of nkBracketExpr: result = foldArrayAccess(m, n, g)
-  of nkDotExpr: result = foldFieldAccess(m, n, g)
+  of nkBracketExpr: result = foldArrayAccess(m, n, idgen, g)
+  of nkDotExpr: result = foldFieldAccess(m, n, idgen, g)
+  of nkCheckedFieldExpr:
+    assert n[0].kind == nkDotExpr
+    result = foldFieldAccess(m, n[0], idgen, g)
   of nkStmtListExpr:
     var i = 0
     while i <= n.len - 2:
       if n[i].kind in {nkComesFrom, nkCommentStmt, nkEmpty}: i.inc
       else: break
     if i == n.len - 1:
-      result = getConstExpr(m, n[i], g)
+      result = getConstExpr(m, n[i], idgen, g)
   else:
     discard