diff --git a/src/regex.nim b/src/regex.nim
index 24f4a53..8580174 100644
--- a/src/regex.nim
+++ b/src/regex.nim
@@ -188,7 +188,7 @@ This means the whole text needs to match the regex for this function to return `
 .. code-block:: nim
     :test:
     let text = "nim c --styleCheck:hint --colors:off regex.nim"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     if match(text, re2"nim c (?:--(\w+:\w+) *)+ (\w+).nim", m):
       doAssert text[m.group(0)] == "colors:off"
       doAssert text[m.group(1)] == "regex"
@@ -229,7 +229,7 @@ match a given regex.
     """
     var match = ""
     var capture = ""
-    var m: RegexMatch2
+    var m = RegexMatch2()
     if find(text, re2"(\w+)@\w+\.\w+", m):
       match = text[m.boundaries]
       capture = text[m.group(0)]
@@ -509,7 +509,7 @@ func group*(m: RegexMatch2, i: int): Slice[int] {.inline, raises: [].} =
   ## and they are included same as in PCRE.
   runnableExamples:
     let text = "abc"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     doAssert text.match(re2"(\w)+", m)
     doAssert text[m.group(0)] == "c"
 
@@ -521,7 +521,7 @@ func group*(
   ## return slices for a given named group
   runnableExamples:
     let text = "abc"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     doAssert text.match(re2"(?P<foo>\w)+", m)
     doAssert text[m.group("foo")] == "c"
 
@@ -530,7 +530,7 @@ func group*(
 func groupsCount*(m: RegexMatch2): int {.inline, raises: [].} =
   ## return the number of capturing groups
   runnableExamples:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     doAssert "ab".match(re2"(a)(b)", m)
     doAssert m.groupsCount == 2
 
@@ -540,7 +540,7 @@ func groupNames*(m: RegexMatch2): seq[string] {.inline, raises: [].} =
   ## return the names of capturing groups.
   runnableExamples:
     let text = "hello world"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     doAssert text.match(re2"(?P<greet>hello) (?P<who>world)", m)
     doAssert m.groupNames == @["greet", "who"]
 
@@ -581,7 +581,7 @@ func match*(
   ## is similar to ``find(text, re"^regex$", m)``
   ## but has better performance
   runnableExamples:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     doAssert "abcd".match(re2"abcd", m)
     doAssert not "abcd".match(re2"abc", m)
 
@@ -590,7 +590,7 @@ func match*(
 
 func match*(s: string, pattern: Regex2): bool {.raises: [].} =
   debugCheckUtf8(s, pattern)
-  var m: RegexMatch2
+  var m = RegexMatch2()
   result = matchImpl(s, pattern.toRegex, m)
 
 when defined(noRegexOpt):
@@ -631,8 +631,8 @@ iterator findAll*(
   debugCheckUtf8(s, pattern)
   var i = start
   var i2 = start-1
-  var m: RegexMatch2
-  var ms: RegexMatches2
+  var m = RegexMatch2()
+  var ms = RegexMatches2()
   while i <= len(s):
     doAssert(i > i2); i2 = i
     i = findSomeOptTpl(s, pattern.toRegex, ms, i)
@@ -649,6 +649,7 @@ func findAll*(
   pattern: Regex2,
   start = 0
 ): seq[RegexMatch2] {.raises: [].} =
+  result = newSeq[RegexMatch2]()
   for m in findAll(s, pattern, start):
     result.add m
 
@@ -670,7 +671,7 @@ iterator findAllBounds*(
   debugCheckUtf8(s, pattern)
   var i = start
   var i2 = start-1
-  var ms: RegexMatches2
+  var ms = RegexMatches2()
   let flags = {mfNoCaptures}
   while i <= len(s):
     doAssert(i > i2); i2 = i
@@ -687,6 +688,7 @@ func findAllBounds*(
   pattern: Regex2,
   start = 0
 ): seq[Slice[int]] {.raises: [].} =
+  result = newSeq[Slice[int]]()
   for m in findAllBounds(s, pattern, start):
     result.add m
 
@@ -699,7 +701,7 @@ func find*(
   ## search through the string looking for the first
   ## location where there is a match
   runnableExamples:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     doAssert "abcd".find(re2"bc", m) and
       m.boundaries == 1 .. 2
     doAssert not "abcd".find(re2"de", m)
@@ -738,7 +740,7 @@ iterator split*(s: string, sep: Regex2): string {.inline, raises: [].} =
     first, last, i = 0
     i2 = -1
     done = false
-    ms: RegexMatches2
+    ms = RegexMatches2()
     flags = {mfNoCaptures}
   while not done:
     doAssert(i > i2); i2 = i
@@ -757,6 +759,7 @@ func split*(s: string, sep: Regex2): seq[string] {.raises: [].} =
     doAssert split("11a22Ϊ33Ⓐ44弢55", re2"\d+") ==
       @["", "a", "Ϊ", "Ⓐ", "弢", ""]
 
+  result = newSeq[string]()
   for w in split(s, sep):
     result.add w
 
@@ -770,12 +773,13 @@ func splitIncl*(s: string, sep: Regex2): seq[string] {.raises: [].} =
 
   template ab: untyped = m.boundaries
   debugCheckUtf8(s, sep)
+  result = newSeq[string]()
   var
     first, last, i = 0
     i2 = -1
     done = false
-    m: RegexMatch2
-    ms: RegexMatches2
+    m = RegexMatch2()
+    ms = RegexMatches2()
   while not done:
     doAssert(i > i2); i2 = i
     i = findSomeOptTpl(s, sep.toRegex, ms, i)
@@ -967,7 +971,7 @@ proc toString(
 proc toString(pattern: Regex2): string {.used.} =
   ## NFA to string representation.
   ## For debugging purposes
-  var visited: set[int16]
+  var visited: set[int16] = {}
   result = pattern.toString(0, visited)
 
 #
@@ -1013,6 +1017,7 @@ func group*(
 func groupFirstCapture*(
   m: RegexMatch, i: int, text: string
 ): string {.inline, raises: [], deprecated.} =
+  result = ""
   for bounds in m.group i:
     return text[bounds]
 
@@ -1083,7 +1088,7 @@ func match*(
 
 func match*(s: string, pattern: Regex): bool {.raises: [], deprecated: "use match(string, Regex2) instead".} =
   debugCheckUtf8 s
-  var m: RegexMatch
+  var m = RegexMatch()
   result = matchImpl(s, pattern, m)
 
 iterator findAll*(
@@ -1094,8 +1099,8 @@ iterator findAll*(
   debugCheckUtf8 s
   var i = start
   var i2 = start-1
-  var m: RegexMatch
-  var ms: RegexMatches
+  var m = RegexMatch()
+  var ms = RegexMatches()
   while i <= len(s):
     doAssert(i > i2); i2 = i
     i = findSomeOptTpl(s, pattern, ms, i)
@@ -1112,6 +1117,7 @@ func findAll*(
   pattern: Regex,
   start = 0
 ): seq[RegexMatch] {.raises: [], deprecated: "use findAll(string, Regex2) instead".} =
+  result = newSeq[RegexMatch]()
   for m in findAll(s, pattern, start):
     result.add m
 
@@ -1123,7 +1129,7 @@ iterator findAllBounds*(
   debugCheckUtf8 s
   var i = start
   var i2 = start-1
-  var ms: RegexMatches
+  var ms = RegexMatches()
   while i <= len(s):
     doAssert(i > i2); i2 = i
     i = findSomeOptTpl(s, pattern, ms, i)
@@ -1139,12 +1145,14 @@ func findAllBounds*(
   pattern: Regex,
   start = 0
 ): seq[Slice[int]] {.raises: [], deprecated: "use findAllBounds(string, Regex2) instead".} =
+  result = newSeq[Slice[int]]()
   for m in findAllBounds(s, pattern, start):
     result.add m
 
 func findAndCaptureAll*(
   s: string, pattern: Regex
 ): seq[string] {.raises: [], deprecated: "use findAll(string, Regex2) instead".} =
+  result = newSeq[string]()
   for m in s.findAll(pattern):
     result.add s[m.boundaries]
 
@@ -1173,7 +1181,7 @@ iterator split*(s: string, sep: Regex): string {.inline, raises: [], deprecated:
     first, last, i = 0
     i2 = -1
     done = false
-    ms: RegexMatches
+    ms = RegexMatches()
   while not done:
     doAssert(i > i2); i2 = i
     i = findSomeOptTpl(s, sep, ms, i)
@@ -1186,18 +1194,20 @@ iterator split*(s: string, sep: Regex): string {.inline, raises: [], deprecated:
       first = ab.b+1
 
 func split*(s: string, sep: Regex): seq[string] {.raises: [], deprecated: "use split(string, Regex2) instead".} =
+  result = newSeq[string]()
   for w in split(s, sep):
     result.add w
 
 func splitIncl*(s: string, sep: Regex): seq[string] {.raises: [], deprecated: "use splitIncl(string, Regex2) instead".} =
   template ab: untyped = m.boundaries
   debugCheckUtf8 s
+  result = newSeq[string]()
   var
     first, last, i = 0
     i2 = -1
     done = false
-    m: RegexMatch
-    ms: RegexMatches
+    m = RegexMatch()
+    ms = RegexMatches()
   while not done:
     doAssert(i > i2); i2 = i
     i = findSomeOptTpl(s, sep, ms, i)
@@ -1231,7 +1241,7 @@ func endsWith*(s: string, pattern: Regex): bool {.raises: [], deprecated: "use e
   debugCheckUtf8 s
   result = false
   var
-    m: RegexMatch
+    m = default(RegexMatch)
     i = 0
   while i < s.len:
     result = match(s, pattern, m, i)
@@ -1329,7 +1339,7 @@ proc toString(
 proc toString(pattern: Regex): string {.used.} =
   ## NFA to string representation.
   ## For debugging purposes
-  var visited: set[int16]
+  var visited: set[int16] = {}
   result = pattern.toString(0, visited)
 
 {.pop.}  # {.push warning[Deprecated]: off.}
@@ -1340,7 +1350,7 @@ when isMainModule:
   import ./regex/dotgraph
 
   func toAtoms(s: string): string =
-    var groups: GroupsCapture
+    var groups = default(GroupsCapture)
     let atoms = s
       .parse
       .toAtoms(groups)
@@ -1403,7 +1413,7 @@ when isMainModule:
   doAssert r"[[:xdigit:]]".toAtoms == "[[0-9a-fA-F]]"
   doAssert r"[[:alpha:][:digit:]]".toAtoms == "[[a-zA-Z][0-9]]"
 
-  var m: RegexMatch2
+  var m = RegexMatch2()
   #doAssert match("abc", re2(r"abc", {reAscii}), m)
   doAssert match("abc", re2"abc", m)
   doAssert match("ab", re2"a(b|c)", m)
@@ -1571,6 +1581,7 @@ when isMainModule:
 
   # subset of tests.nim
   proc raisesMsg(pattern: string): string =
+    result = ""
     try:
       discard re2(pattern)
     except RegexError:
@@ -1582,7 +1593,7 @@ when isMainModule:
     (proc() = body)()
 
   test:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     doAssert match("ac", re2"a(b|c)", m)
     doAssert(not match("ad", re2"a(b|c)", m))
     doAssert match("ab", re2"(ab)*", m)
@@ -1692,7 +1703,7 @@ when isMainModule:
       m.captures == @[0 .. 3, reNonCapture, reNonCapture]
     block:
       var m = false
-      var matches: seq[string]
+      var matches = newSeq[string]()
       match "abc", rex"(\w+)":
         doAssert matches == @["abc"]
         m = true
diff --git a/src/regex/common.nim b/src/regex/common.nim
index 63f37b2..c4fc6fa 100644
--- a/src/regex/common.nim
+++ b/src/regex/common.nim
@@ -70,6 +70,7 @@ type
 func verifyUtf8*(s: string): int =
   ## Return `-1` if `s` is a valid utf-8 string.
   ## Otherwise, return the index of the first bad char.
+  result = -1
   var state = vusStart
   var i = 0
   let L = s.len
diff --git a/src/regex/compiler.nim b/src/regex/compiler.nim
index 275976e..666dcc5 100644
--- a/src/regex/compiler.nim
+++ b/src/regex/compiler.nim
@@ -11,7 +11,7 @@ when defined(regexDotDir):
 func reImpl*(s: string, flags: RegexFlags = {}): Regex =
   if regexArbitraryBytes notin flags and verifyUtf8(s) != -1:
     raise newException(RegexError, "Invalid utf-8 regex")
-  var groups: GroupsCapture
+  var groups = default(GroupsCapture)
   let rpn = s
     .parse(flags)
     .transformExp(groups, flags)
diff --git a/src/regex/dotgraph.nim b/src/regex/dotgraph.nim
index e995b17..6b3048b 100644
--- a/src/regex/dotgraph.nim
+++ b/src/regex/dotgraph.nim
@@ -8,6 +8,7 @@ import ./types
 func getEpsilonTransitions(nfa: Nfa, n: Node, nti: int): seq[int] =
   doAssert not isEpsilonTransition(n)
   doAssert nti <= n.next.len-1
+  result = newSeq[int]()
   for i in nti+1 .. n.next.len-1:
     if not isEpsilonTransition(nfa.s[n.next[i]]):
       break
diff --git a/src/regex/exptransformation.nim b/src/regex/exptransformation.nim
index b643e5a..bc21759 100644
--- a/src/regex/exptransformation.nim
+++ b/src/regex/exptransformation.nim
@@ -28,6 +28,7 @@ template check(cond, msg: untyped): untyped =
 func fixEmptyOps(exp: Exp): Exp =
   ## Handle "|", "(|)", "a|", "|b", "||", "a||b", ...
   ## Handle "()"
+  result = default(Exp)
   result.s = newSeq[Node](exp.s.len)
   result.s.setLen 0
   for i in 0 .. exp.s.len-1:
@@ -46,6 +47,7 @@ func fixEmptyOps(exp: Exp): Exp =
 
 func greediness(exp: Exp): Exp =
   ## apply greediness to an expression
+  result = default(Exp)
   result.s = newSeq[Node](exp.s.len)
   result.s.setLen 0
   var sc = exp.s.scan()
@@ -156,6 +158,7 @@ func squash(flags: seq[seq[Flag]]): array[Flag, bool] =
   ## this will set/unset those flags
   ## in order. It should be done each time
   ## there is a group start/end
+  result = default(array[Flag, bool])
   for ff in flags:
     for f in ff:
       result[f.toggle()] = false
@@ -212,6 +215,7 @@ func applyFlag(n: var Node, f: Flag) =
 
 func applyFlags(exp: Exp, fls: RegexFlags): Exp =
   ## apply flags to each group
+  result = default(Exp)
   result.s = newSeq[Node](exp.s.len)
   result.s.setLen 0
   var flags = newSeq[seq[Flag]]()
@@ -276,6 +280,7 @@ func expandOneRepRange(subExpr: seq[Node], n: Node): seq[Node] =
 
 func expandRepRange(exp: Exp): Exp =
   ## expand every repetition range
+  result = default(Exp)
   result.s = newSeq[Node](exp.s.len)
   result.s.setLen 0
   var i: int
@@ -314,6 +319,7 @@ func expandRepRange(exp: Exp): Exp =
          "expected before repetition range"))
 
 func expandArbitrayBytes(exp: Exp, flags: RegexFlags): Exp =
+  result = default(Exp)
   if regexArbitraryBytes notin flags:
     return exp
   template addBytes(result, node, n: untyped): untyped =
@@ -361,6 +367,7 @@ func joinAtoms(exp: Exp): AtomsExp =
   ## Put a ``~`` joiner between atoms. An atom is
   ## a piece of expression that would loose
   ## meaning when breaking it up (i.e.: ``a~(b|c)*~d``)
+  result = default(AtomsExp)
   result.s = newSeq[Node](exp.s.len * 2)
   result.s.setLen 0
   var atomsCount = 0
@@ -407,13 +414,14 @@ func opsPA(nk: NodeKind): OpsPA =
       reZeroOrMore,
       reOneOrMore,
       reZeroOrOne:
-    result = (5, asyRight)
+    (5, asyRight)
   of reJoiner:
-    result = (4, asyLeft)
+    (4, asyLeft)
   of reOr:
-    result = (3, asyLeft)
+    (3, asyLeft)
   else:
     doAssert false
+    default(OpsPA)
 
 func hasPrecedence(a: NodeKind, b: NodeKind): bool =
   ## Check ``b`` has precedence over ``a``.
@@ -454,6 +462,7 @@ func rpn(exp: AtomsExp): RpnExp =
   ## the parsing of the regular expression into an NFA.
   ## Suffix notation removes nesting and so it can
   ## be parsed in a linear way instead of recursively
+  result = default(RpnExp)
   result.s = newSeq[Node](exp.s.len)
   result.s.setLen 0
   var ops = newSeq[Node]()
@@ -478,6 +487,7 @@ func rpn(exp: AtomsExp): RpnExp =
 func subExps(exp: AtomsExp, parentKind = reLookahead): AtomsExp =
   ## Collect and convert lookaround sub-expressions to RPN
   template n: untyped = result.s[^1]
+  result = default(AtomsExp)
   result.s = newSeq[Node](exp.s.len)
   result.s.setLen 0
   var i = 0
diff --git a/src/regex/litopt.nim b/src/regex/litopt.nim
index b91fa35..4945c06 100644
--- a/src/regex/litopt.nim
+++ b/src/regex/litopt.nim
@@ -87,6 +87,7 @@ func update(
 # and (...|...) by skip nodes.
 # Based on Thompson's construction
 func toLitNfa(exp: RpnExp): LitNfa =
+  result = default(LitNfa)
   result.s = newSeq[Node](exp.s.len + 2)
   result.s.setLen 0
   result.s.add initEoeNode()
@@ -175,6 +176,7 @@ type
     s: string
 
 func find(nodes: seq[Node], uid: int): NodeIdx =
+  result = default(NodeIdx)
   for idx in 0 .. nodes.len-1:
     if nodes[idx].uid == uid:
       return idx.NodeIdx
@@ -182,6 +184,7 @@ func find(nodes: seq[Node], uid: int): NodeIdx =
 
 func lits(exp: RpnExp, flags: RegexFlags): Lits =
   template state: untyped = litNfa.s[stateIdx]
+  result = default(Lits)
   result.idx = exp.delimiterLit()
   if result.idx == -1:
     return
@@ -230,7 +233,7 @@ func prefix(eNfa: Enfa, uid: NodeUid): Enfa =
     n.next.setLen 0
   # reverse transitions; DFS
   var stack = @[(state0, -1'i16)]
-  var visited: set[int16]
+  var visited: set[int16] = {}
   template state: untyped = eNfa.s[ni]
   while stack.len > 0:
     let (ni, pi) = stack.pop()
@@ -283,6 +286,7 @@ func canOpt*(litOpt: LitOpt): bool =
 
 func litopt3*(exp: RpnExp, flags: RegexFlags = {}): LitOpt =
   template litNode: untyped = exp.s[lits2.idx]
+  result = default(LitOpt)
   let lits2 = exp.lits(flags)
   if lits2.idx == -1:
     return
diff --git a/src/regex/nfa.nim b/src/regex/nfa.nim
index 96567b9..4515f4a 100644
--- a/src/regex/nfa.nim
+++ b/src/regex/nfa.nim
@@ -50,6 +50,7 @@ func update(
 
 func eNfa*(exp: RpnExp): Enfa {.raises: [RegexError].} =
   ## Thompson's construction
+  result = default(Enfa)
   result.s = newSeq[Node](exp.s.len + 2)
   result.s.setLen 0
   result.s.add initEOENode()
@@ -190,7 +191,7 @@ func teClosure(
   processing: var seq[int16]
 ) =
   doAssert processing.len == 0
-  var transitions: Transitions
+  var transitions = default(Transitions)
   for s in eNfa.s[state].next:
     teClosure(result, eNfa, s, processing, transitions)
 
@@ -201,6 +202,7 @@ func eRemoval*(eNfa: Enfa): Nfa {.raises: [].} =
   ## Transitions are added in matching order (BFS),
   ## which may help matching performance
   #echo eNfa
+  result = default(Nfa)
   result.s = newSeq[Node](eNfa.s.len)
   result.s.setLen 0
   var statesMap = newSeq[int16](eNfa.s.len)
@@ -209,12 +211,12 @@ func eRemoval*(eNfa: Enfa): Nfa {.raises: [].} =
   let start = int16(eNfa.s.len-1)
   result.s.add eNfa.s[start]
   statesMap[start] = 0'i16
-  var closure: TeClosure
+  var closure = default(TeClosure)
   var qw = initDeque[int16](2)
   qw.addFirst start
-  var qu: set[int16]
+  var qu: set[int16] = {}
   qu.incl start
-  var qa: int16
+  var qa = 0'i16
   var processing = newSeqOfCap[int16](8)
   while qw.len > 0:
     try:
@@ -245,7 +247,7 @@ func reverse(eNfa: Enfa): Enfa =
   for n in mitems result.s:
     n.next.setLen 0
   var stack = @[(state0, -1'i16)]
-  var visited: set[int16]
+  var visited: set[int16] = {}
   template state: untyped = eNfa.s[ni]
   while stack.len > 0:
     let (ni, pi) = stack.pop()
diff --git a/src/regex/nfafindall2.nim b/src/regex/nfafindall2.nim
index 48d290f..f0d9255 100644
--- a/src/regex/nfafindall2.nim
+++ b/src/regex/nfafindall2.nim
@@ -139,7 +139,7 @@ func dummyMatch*(ms: var RegexMatches2, i: int) =
   if ms.m.len == 0 or max(ab.a, ab.b) < i:
     ms.add (-1'i32, i+1 .. i)
 
-func submatch(
+func nextState(
   ms: var RegexMatches2,
   text: string,
   regex: Regex,
@@ -176,26 +176,9 @@ func submatch(
       captx = capt
       while nti < L and isEpsilonTransition(ntn):
         if matched:
-          case ntn.kind
-          of reGroupStart:
-            if mfNoCaptures notin flags:
-              captx = capts.diverge captx
-              capts[captx, ntn.idx].a = i
-          of reGroupEnd:
-            if mfNoCaptures notin flags:
-              captx = capts.diverge captx
-              capts[captx, ntn.idx].b = i-1
-          of assertionKind - lookaroundKind:
-            matched = match(ntn, cPrev.Rune, c.Rune)
-          of lookaroundKind:
-            let freezed = capts.freeze()
-            matched = lookAround(ntn, capts, captx, text, look, i, flags)
-            capts.unfreeze freezed
-            if captx != -1:
-              capts.keepAlive captx
-          else:
-            doAssert false
-            discard
+          epsilonMatch(
+            matched, captx, capts, look, ntn, text, i, cPrev, c.Rune, flags
+          )
         inc nti
       if matched:
         if isEoe:
@@ -243,7 +226,7 @@ func findSomeImpl*(
       inc i
     else:
       fastRuneAt(text, i, c, true)
-    submatch(ms, text, regex, iPrev, cPrev, c.int32, flags)
+    nextState(ms, text, regex, iPrev, cPrev, c.int32, flags)
     if smA.len == 0:
       # avoid returning right before final zero-match
       if i < len(text):
@@ -256,7 +239,7 @@ func findSomeImpl*(
     smA.add (0'i16, -1'i32, i .. i-1)
     iPrev = i
     cPrev = c.int32
-  submatch(ms, text, regex, iPrev, cPrev, -1'i32, flags)
+  nextState(ms, text, regex, iPrev, cPrev, -1'i32, flags)
   doAssert smA.len == 0
   if ms.hasMatches():
     #debugEcho "m= ", ms.m.s
diff --git a/src/regex/nfamacro.nim b/src/regex/nfamacro.nim
index b6355a1..f31fc83 100644
--- a/src/regex/nfamacro.nim
+++ b/src/regex/nfamacro.nim
@@ -156,7 +156,7 @@ func genMatch(c: NimNode, n: Node): NimNode =
 
 func genSetMatch(c: NimNode, n: Node): NimNode =
   assert n.kind in {reInSet, reNotSet}
-  var terms: seq[NimNode]
+  var terms = newSeq[NimNode]()
   if n.ranges.len > 0:
     for bound in n.ranges:
       let a = newLit bound.a.int32
@@ -164,7 +164,7 @@ func genSetMatch(c: NimNode, n: Node): NimNode =
       terms.add quote do:
         `a` <= `c` and `c` <= `b`
   if n.cps.len > 0:
-    var caseStmt: seq[NimNode]
+    var caseStmt = newSeq[NimNode]()
     caseStmt.add c
     for cp in n.cps:
       caseStmt.add newTree(nnkOfBranch,
@@ -268,6 +268,7 @@ func genLookaroundMatch(
 func getEpsilonTransitions(nfa: Nfa, n: Node, nti: int): seq[int] =
   doAssert not isEpsilonTransition(n)
   doAssert nti <= n.next.len-1
+  result = newSeq[int]()
   for i in nti+1 .. n.next.len-1:
     if not isEpsilonTransition(nfa.s[n.next[i]]):
       break
@@ -291,7 +292,7 @@ func genMatchedBody(
   if eTransitions.len == 0:
     return quote do:
       add(`smB`, (`ntLit`, `capt`, `bounds2`))
-  var matchedBody: seq[NimNode]
+  var matchedBody = newSeq[NimNode]()
   matchedBody.add quote do:
     `matched` = true
     `captx` = `capt`
@@ -349,14 +350,14 @@ func genNextState(
   ]#
   template s: untyped = nfa.s
   result = newStmtList()
-  var caseStmtN: seq[NimNode]
+  var caseStmtN = newSeq[NimNode]()
   caseStmtN.add n
   for i in 0 .. s.len-1:
     if s[i].kind == reEoe:
       continue
     if isEpsilonTransition(s[i]):
       continue
-    var branchBodyN: seq[NimNode]
+    var branchBodyN = newSeq[NimNode]()
     for nti, nt in s[i].next.pairs:
       if eoeOnly and s[nt].kind != reEoe:
         continue
@@ -436,6 +437,7 @@ func nextState(
     swap `smA`, `smB`
 
 func eoeIdx(nfa: Nfa): int16 =
+  result = 0'i16
   for i in 0 .. nfa.s.len-1:
     if nfa.s[i].kind == reEoe:
       return i.int16
@@ -556,7 +558,7 @@ template look(smL: NimNode): untyped =
 template constructSubmatches2(
   captures, txt, capts, capt, size: untyped
 ): untyped =
-  var bounds: array[size, Slice[int]]
+  var bounds = default(array[size, Slice[int]])
   for i in 0 .. bounds.len-1:
     bounds[i] = -2 .. -3
   var captx = capt
@@ -588,13 +590,13 @@ proc matchImpl*(text, expLit, body: NimNode): NimNode =
       var
         `smA` = newSubmatches `nfaLenLit`
         `smB` = newSubmatches `nfaLenLit`
-        `capts`: Capts
+        `capts` = default(Capts)
         `capt` = -1'i32
         `matched` = false
-        `smL` {.used.}: SmLookaround
+        `smL` {.used.} = default(SmLookaround)
       `matchImplStmt`
       if `matched`:
-        var matches {.used, inject.}: seq[string]
+        var matches {.used, inject.} = newSeq[string]()
         when `nfaGroupsLen` > 0:
           constructSubmatches2(
             matches, `text`, `capts`, `capt`, `nfaGroupsLen`)
diff --git a/src/regex/nfamatch.nim b/src/regex/nfamatch.nim
index f37b003..17c994d 100644
--- a/src/regex/nfamatch.nim
+++ b/src/regex/nfamatch.nim
@@ -204,10 +204,11 @@ func reversedMatchImpl*(
   look: var Lookaround,
   start, limit: int
 ): int =
-  var capts: Capts
+  var capts = default(Capts)
   var captIdx = -1'i32
   reversedMatchImpl(
-    smA, smB, capts, captIdx, text, nfa, look, start, limit)
+    smA, smB, capts, captIdx, text, nfa, look, start, limit
+  )
 
 template initLook*: Lookaround =
   Lookaround(
@@ -224,7 +225,7 @@ func matchImpl*(
   var
     smA = newSubmatches(regex.nfa.s.len)
     smB = newSubmatches(regex.nfa.s.len)
-    capts: Capts
+    capts = default(Capts)
     capt = -1'i32
     look = initLook()
   result = matchImpl(
@@ -242,7 +243,7 @@ func startsWithImpl*(text: string, regex: Regex, start: int): bool =
   var
     smA = newSubmatches(regex.nfa.s.len)
     smB = newSubmatches(regex.nfa.s.len)
-    capts: Capts
+    capts = default(Capts)
     capt = -1'i32
     look = initLook()
   result = matchImpl(
diff --git a/src/regex/nfamatch2.nim b/src/regex/nfamatch2.nim
index fb4bcd3..f14868f 100644
--- a/src/regex/nfamatch2.nim
+++ b/src/regex/nfamatch2.nim
@@ -34,7 +34,7 @@ type
     behind*: BehindSig
     smL*: SmLookaround
 
-func lookAround*(
+func lookAround(
   ntn: Node,
   capts: var Capts3,
   captIdx: var int32,
@@ -76,22 +76,76 @@ func lookAround*(
     false
   smL.removeLast()
 
-template nextStateTpl(bwMatch = false): untyped {.dirty.} =
-  template bounds2: untyped =
-    when bwMatch: i .. bounds.b else: bounds.a .. i-1
+func epsilonMatch*(
+  matched: var bool,
+  captx: var int32,
+  capts: var Capts3,
+  look: var Lookaround,
+  ntn: Node,
+  text: string,
+  i: int,
+  cPrev: int32,
+  c: Rune,
+  flags: MatchFlags,
+  bwMatch = false
+) =
   template captElm: untyped =
-    capts[captx, nfa.s[nt].idx]
-  template nt: untyped = nfa.s[n].next[nti]
-  template ntn: untyped = nfa.s[nt]
+    capts[captx, ntn.idx]
+  case ntn.kind
+  of reGroupStart:
+    captx = capts.diverge captx
+    if mfReverseCapts notin flags or
+        captElm.a == nonCapture.a:
+      captElm.a = i
+  of reGroupEnd:
+    captx = capts.diverge captx
+    if mfReverseCapts notin flags or
+        captElm.b == nonCapture.b:
+      captElm.b = i-1
+  of assertionKind - lookaroundKind:
+    if bwMatch:
+      matched = match(ntn, c, cPrev.Rune)
+    else:
+      matched = match(ntn, cPrev.Rune, c)
+  of lookaroundKind:
+    let freezed = capts.freeze()
+    matched = lookAround(ntn, capts, captx, text, look, i, flags)
+    capts.unfreeze freezed
+    if captx != -1:
+      capts.keepAlive captx
+  else:
+    doAssert false
+    discard
+
+func nextState(
+  smA, smB: var Submatches,
+  capts: var Capts3,
+  look: var Lookaround,
+  text: string,
+  nfa2: Nfa,
+  i: int,
+  cPrev: int32,
+  c: Rune,
+  flags: MatchFlags,
+  bwMatch = false
+) {.inline.} =
+  template nfa: untyped = nfa2.s
+  template bounds2: untyped =
+    if bwMatch: i .. bounds.b else: bounds.a .. i-1
+  template nt: untyped = nfa[n].next[nti]
+  template ntn: untyped = nfa[nt]
+  let anchored = mfAnchored in flags
+  var captx = 0'i32
+  var matched = true
   smB.clear()
   for n, capt, bounds in items smA:
     if capt != -1:
       capts.keepAlive capt
-    if anchored and nfa.s[n].kind == reEoe:
+    if anchored and nfa[n].kind == reEoe:
       if not smB.hasState n:
         smB.add (n, capt, bounds)
       break
-    let L = nfa.s[n].next.len
+    let L = nfa[n].next.len
     var nti = 0
     while nti < L:
       let nt0 = nt
@@ -101,32 +155,9 @@ template nextStateTpl(bwMatch = false): untyped {.dirty.} =
       captx = capt
       while nti < L and isEpsilonTransition(ntn):
         if matched:
-          case ntn.kind
-          of reGroupStart:
-            # XXX this can be avoided in some cases?
-            captx = capts.diverge captx
-            if mfReverseCapts notin flags or
-                captElm.a == nonCapture.a:
-              captElm.a = i
-          of reGroupEnd:
-            captx = capts.diverge captx
-            if mfReverseCapts notin flags or
-                captElm.b == nonCapture.b:
-              captElm.b = i-1
-          of assertionKind - lookaroundKind:
-            when bwMatch:
-              matched = match(ntn, c, cPrev.Rune)
-            else:
-              matched = match(ntn, cPrev.Rune, c)
-          of lookaroundKind:
-            let freezed = capts.freeze()
-            matched = lookAround(ntn, capts, captx, text, look, i, flags)
-            capts.unfreeze freezed
-            if captx != -1:
-              capts.keepAlive captx
-          else:
-            doAssert false
-            discard
+          epsilonMatch(
+            matched, captx, capts, look, ntn, text, i, cPrev, c, flags, bwMatch
+          )
         inc nti
       if matched:
         smB.add (nt0, captx, bounds2)
@@ -148,8 +179,6 @@ func matchImpl(
     cPrev = -1'i32
     i = start
     iNext = start
-    captx = -1'i32
-    matched = false
   let
     anchored = mfAnchored in flags
     binFlag = mfBytesInput in flags
@@ -166,7 +195,7 @@ func matchImpl(
       inc iNext
     else:
       fastRuneAt(text, iNext, c, true)
-    nextStateTpl()
+    nextState(smA, smB, capts, look, text, nfa, i, cPrev, c, flags)
     if smA.len == 0:
       return false
     if anchored and nfa.s[smA[0].ni].kind == reEoe:
@@ -174,7 +203,7 @@ func matchImpl(
     i = iNext
     cPrev = c.int32
   c = Rune(-1)
-  nextStateTpl()
+  nextState(smA, smB, capts, look, text, nfa, i, cPrev, c, flags)
   if smA.len > 0:
     captIdx = smA[0].ci
   return smA.len > 0
@@ -197,9 +226,7 @@ func reversedMatchImpl(
     cPrev = -1'i32
     i = start
     iNext = start
-    captx: int32
-    matched = false
-    anchored = true
+  let flags = flags + {mfAnchored}
   let binFlag = mfBytesInput in flags
   if start in 0 .. text.len-1:
     cPrev = if binFlag:
@@ -214,7 +241,7 @@ func reversedMatchImpl(
       dec iNext
     else:
       bwFastRuneAt(text, iNext, c)
-    nextStateTpl(bwMatch = true)
+    nextState(smA, smB, capts, look, text, nfa, i, cPrev, c, flags, bwMatch = true)
     if smA.len == 0:
       return -1
     if nfa.s[smA[0].ni].kind == reEoe:
@@ -228,7 +255,7 @@ func reversedMatchImpl(
       dec iNext
     else:
       bwFastRuneAt(text, iNext, c)
-  nextStateTpl(bwMatch = true)
+  nextState(smA, smB, capts, look, text, nfa, i, cPrev, c, flags, bwMatch = true)
   for n, capt, bounds in items smA:
     if nfa.s[n].kind == reEoe:
       captIdx = capt
diff --git a/src/regex/nfatype.nim b/src/regex/nfatype.nim
index 981a1ef..dbbd03b 100644
--- a/src/regex/nfatype.nim
+++ b/src/regex/nfatype.nim
@@ -66,10 +66,13 @@ template fastLog2Tpl(x: Natural): untyped =
       fastLog2(x)
 
 func initCapts3*(groupsLen: int): Capts3 =
-  result.groupsLen = groupsLen
-  result.blockSize = max(2, nextPowerOfTwo groupsLen)
-  result.blockSizeL2 = fastLog2Tpl result.blockSize
-  result.freezeId = stsFrozen.a
+  let blockSize = max(2, nextPowerOfTwo groupsLen)
+  Capts3(
+    groupsLen: groupsLen,
+    blockSize: blockSize,
+    blockSizeL2: fastLog2Tpl blockSize,
+    freezeId: stsFrozen.a
+  )
 
 func check(curr, next: CaptState): bool =
   ## Check if transition from state curr to next is allowed
@@ -230,6 +233,7 @@ type
   MatchFlags* = set[MatchFlag]
 
 func toMatchFlags*(f: RegexFlags): MatchFlags =
+  result = default(MatchFlags)
   if regexArbitraryBytes in f:
     result.incl mfBytesInput
 
diff --git a/src/regex/parser.nim b/src/regex/parser.nim
index 4e41af0..a8f1e34 100644
--- a/src/regex/parser.nim
+++ b/src/regex/parser.nim
@@ -175,6 +175,7 @@ func parseOctalLit(sc: Scanner[Rune]): Node =
   result = Rune(cp).toCharNode
 
 func parseCC(s: string): UnicodeCategorySet =
+  result = default(UnicodeCategorySet)
   try:
     result = s.categoryMap.UnicodeCategorySet
   except ValueError:
@@ -235,31 +236,34 @@ func parseEscapedSeq(sc: Scanner[Rune]): Node =
   case sc.peek
   of "u".toRune:
     discard sc.next()
-    result = parseUnicodeLit(sc, 4)
+    parseUnicodeLit(sc, 4)
   of "U".toRune:
     discard sc.next()
-    result = parseUnicodeLit(sc, 8)
+    parseUnicodeLit(sc, 8)
   of "x".toRune:
     discard sc.next()
     case sc.peek
     of "{".toRune:
-      result = parseUnicodeLitX(sc)
+      parseUnicodeLitX(sc)
     else:
-      result = parseUnicodeLit(sc, 2)
+      parseUnicodeLit(sc, 2)
   of "0".toRune .. "7".toRune:
-    result = parseOctalLit(sc)
+    parseOctalLit(sc)
   of "p".toRune:
     discard sc.next()
-    result = parseUnicodeName(sc)
+    parseUnicodeName(sc)
   of "P".toRune:
     discard sc.next()
-    result = parseUnicodeName(sc)
-    result.kind = reNotUCC
+    var node = parseUnicodeName(sc)
+    node.kind = reNotUCC
+    node
   of invalidRune:
     let startPos = sc.pos
     prettyCheck(false, "Nothing to escape")
+    doAssert false
+    Node()
   else:
-    result = next(sc).toEscapedNode
+    next(sc).toEscapedNode
 
 func parseSetEscapedSeq(sc: Scanner[Rune]): Node =
   ## Just like regular ``parseEscapedSeq``
@@ -392,24 +396,23 @@ func parseSet(sc: Scanner[Rune]): Node =
       if cps.len == 0:
         cps.add(cp)
         continue
-      var last: Rune
-      case sc.peek
-      of "]".toRune:
+      if sc.peek == "]".toRune:
         cps.add(cp)
         continue
-      of "\\".toRune:
-        discard sc.next()
-        let nn = parseSetEscapedSeq(sc)
-        check(
-          nn.kind == reChar,
-          "Invalid set range. Range can't contain " &
-          "a character-class or assertion",
-          sc.pos-1,
-          sc.raw)
-        last = nn.cp
-      else:
-        assert(not sc.finished)
-        last = sc.next()
+      var last = case sc.peek
+        of "\\".toRune:
+          discard sc.next()
+          let nn = parseSetEscapedSeq(sc)
+          check(
+            nn.kind == reChar,
+            "Invalid set range. Range can't contain " &
+            "a character-class or assertion",
+            sc.pos-1,
+            sc.raw)
+          nn.cp
+        else:
+          doAssert(not sc.finished)
+          sc.next()
       let first = cps.pop()
       check(
         first <= last,
@@ -453,7 +456,8 @@ func parseRepRange(sc: Scanner[Rune]): Node =
     return Node(kind: reChar, cp: '{'.Rune)
   let startPos = sc.pos
   var
-    first, last: string
+    first = ""
+    last = ""
     hasFirst = false
     curr = ""
   for cp in sc:
@@ -482,8 +486,8 @@ func parseRepRange(sc: Scanner[Rune]): Node =
   if last.len == 0:  # {n,}
     last = "-1"
   var
-    firstNum: int
-    lastNum: int
+    firstNum = 0
+    lastNum = 0
   try:
     discard parseInt(first, firstNum)
     discard parseInt(last, lastNum)
@@ -556,13 +560,12 @@ func parseGroupTag(sc: Scanner[Rune]): Node =
   # A regular group
   let startPos = sc.pos
   if sc.peek != "?".toRune:
-    result = initGroupStart()
-    return
+    return initGroupStart()
   discard sc.next()  # Consume "?"
-  case sc.peek
+  result = case sc.peek
   of ":".toRune:
     discard sc.next()
-    result = initGroupStart(isCapturing = false)
+    initGroupStart(isCapturing = false)
   of "P".toRune:
     discard sc.next()
     prettyCheck(
@@ -589,7 +592,7 @@ func parseGroupTag(sc: Scanner[Rune]): Node =
     prettyCheck(
       sc.prev == ">".toRune,
       "Invalid group name. Missing `>`")
-    result = initGroupStart(name)
+    initGroupStart(name)
   of "i".toRune,
       "m".toRune,
       "s".toRune,
@@ -610,44 +613,39 @@ func parseGroupTag(sc: Scanner[Rune]): Node =
         flags.add toNegFlag(cp)
       else:
         flags.add toFlag(cp)
-    result = if sc.prev == ")".toRune:
+    if sc.prev == ")".toRune:
       Node(kind: reFlags, flags: flags)
     else:
-      initGroupStart(
-        flags = flags,
-        isCapturing = false)
+      initGroupStart(flags = flags, isCapturing = false)
   #reLookahead,
   #reLookbehind,
   of '='.Rune, '<'.Rune, '!'.Rune:
-    var lookAroundKind: NodeKind
-    case sc.peek
-    of '='.Rune:
-      lookAroundKind = reLookahead
-    of '!'.Rune:
-      lookAroundKind = reNotLookahead
-    of '<'.Rune:
-      discard sc.next()
-      case sc.peek:
-      of '='.Rune:
-        lookAroundKind = reLookbehind
-      of '!'.Rune:
-        lookAroundKind = reNotLookbehind
+    var lookAroundKind = case sc.peek
+      of '='.Rune: reLookahead
+      of '!'.Rune: reNotLookahead
+      of '<'.Rune:
+        discard sc.next()
+        case sc.peek:
+        of '='.Rune: reLookbehind
+        of '!'.Rune: reNotLookbehind
+        else:
+          prettyCheck(
+            false, "Invalid lookabehind, expected `<=` or `<!` symbol"
+          )
+          doAssert false
+          reLookbehind
       else:
-        prettyCheck(
-          false,
-          "Invalid lookabehind, expected `<=` or `<!` symbol")
-    else:
-      doAssert false
+        doAssert false
+        reLookbehind
     doAssert sc.peek in ['='.Rune, '!'.Rune]
     discard sc.next
     prettyCheck(
       sc.peek != ')'.Rune,
       "Empty lookaround is not allowed")
-    result = Node(kind: lookAroundKind)
+    Node(kind: lookAroundKind)
   else:
-    prettyCheck(
-      false,
-      "Invalid group. Unknown group type")
+    prettyCheck(false, "Invalid group. Unknown group type")
+    Node()
 
 func subParse(sc: Scanner[Rune]): Node =
   let r = sc.prev
@@ -745,6 +743,7 @@ func verbosity(
 func parse*(expression: string, flags: RegexFlags = {}): Exp =
   ## convert a ``string`` regex expression
   ## into a ``Node`` expression
+  result = default(Exp)
   result.s = newSeq[Node](expression.len)
   result.s.setLen 0
   var vb = newSeq[bool]()
diff --git a/tests/tests.nim b/tests/tests.nim
index b43ce0e..4b6fe26 100644
--- a/tests/tests.nim
+++ b/tests/tests.nim
@@ -27,11 +27,11 @@ template expect(exception: typedesc, body: untyped): untyped =
 
 when defined(forceRegexAtRuntime):
   proc isMatch(s: string, pattern: Regex): bool =
-    var m: RegexMatch
+    var m = RegexMatch()
     result = match(s, pattern, m)
 else:
   proc isMatch(s: string, pattern: static Regex): bool =
-    var m: RegexMatch
+    var m = RegexMatch()
     result = match(s, pattern, m)
 
 proc raises(pattern: string): bool =
@@ -58,12 +58,12 @@ proc toStrCaptures(m: RegexMatch, s: string): seq[seq[string]] =
       inc j
 
 proc matchWithCapt(s: string, pattern: static Regex): seq[seq[string]] =
-  var m: RegexMatch
+  var m = RegexMatch()
   check match(s, pattern, m)
   result = m.toStrCaptures(s)
 
 proc findWithCapt(s: string, pattern: Regex): seq[seq[string]] =
-  var m: RegexMatch
+  var m = RegexMatch()
   check find(s, pattern, m)
   result = m.toStrCaptures(s)
 
@@ -622,12 +622,12 @@ test "tgreediness":
   check "aaa".matchWithCapt(re"(a){1,}?(a){1,}?(a)?") ==
     @[@["a"], @["a"], @["a"]]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check match("aaaa", re"(a*?)(a*?)(a*)", m)
     check m.toStrCaptures("aaaa") ==
       @[@[""], @[""], @["aaaa"]]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check match("aaaa", re"(a*)(a*?)(a*?)", m)
     check m.toStrCaptures("aaaa") ==
       @[@["aaaa"], @[""], @[""]]
@@ -660,20 +660,20 @@ test "tdot_any_matcher":
 
 test "tgroup":
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "foobar".match(re"(\w*)", m)
     check m.group(0) == @[0..5]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "foobar".match(re"(?P<foo>\w*)", m)
     check m.group(0) == @[0..5]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "ab".match(re"(a)(b)", m)
     check m.group(0) == @[0..0]
     check m.group(1) == @[1..1]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check match("ab", re"(a)(b)", m)
     check m.toStrCaptures("ab") ==
       @[@["a"], @["b"]]
@@ -681,7 +681,7 @@ test "tgroup":
     let
       expected = ["a", "b", "c"]
       text = "abc"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<foo>\w)+", m)
     var i = 0
     for bounds in m.group("foo"):
@@ -691,7 +691,7 @@ test "tgroup":
     let
       expected = ["a", "b", "c"]
       text = "abc"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(\w)+", m)
     var i = 0
     for bounds in m.group(0):
@@ -700,21 +700,21 @@ test "tgroup":
 
 test "tnamed_groups":
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "foobar".match(re"(?P<foo>\w*)", m)
     check m.group("foo") == @[0..5]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "foobar".match(re"(?P<foo>(?P<bar>\w*))", m)
     check m.group("foo") == @[0..5]
     check m.group("bar") == @[0..5]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "aab".match(re"(?P<foo>(?P<bar>a)*b)", m)
     check m.group("foo") == @[0..2]
     check m.group("bar") == @[0..0, 1..1]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "aab".match(re"((?P<bar>a)*b)", m)
     check m.group("bar") == @[0..0, 1..1]
 
@@ -926,49 +926,49 @@ test "tescaped_sequences":
 
 test "tfind":
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "abcd".find(re"bc", m)
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check(not "abcd".find(re"ac", m))
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "a".find(re"", m)
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "abcd".find(re"^abcd$", m)
   check "2222".findWithCapt(re"(22)*") ==
     @[@["22", "22"]]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "2222".find(re"(22)*", m)
     check m.group(0) == @[0 .. 1, 2 .. 3]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "abcd".find(re"(ab)", m)
     check m.group(0) == @[0 .. 1]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "abcd".find(re"(bc)", m)
     check m.group(0) == @[1 .. 2]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "abcd".find(re"(cd)", m)
     check m.group(0) == @[2 .. 3]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "abcd".find(re"bc", m)
     check m.boundaries == 1 .. 2
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "aΪⒶ弢".find(re"Ϊ", m)
     check m.boundaries == 1 .. 2
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "aΪⒶ弢".find(re"Ⓐ", m)
     check m.boundaries == 3 .. 5
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "aΪⒶ弢".find(re"弢", m)
     check m.boundaries == 6 .. 9
 
@@ -1344,17 +1344,17 @@ test "treplace":
 
 test "tmisc":
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "abc".match(re"[^^]+", m)
     check m.boundaries == 0 .. 2
   check(not "^".isMatch(re"[^^]+"))
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "kpd".match(re"[^al-obc]+", m)
     check m.boundaries == 0 .. 2
   check(not "abc".isMatch(re"[^al-obc]+"))
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "almocb".match(re"[al-obc]+", m)
     check m.boundaries == 0 .. 5
   check(not "defzx".isMatch(re"[al-obc]+"))
@@ -1362,7 +1362,7 @@ test "tmisc":
   # From http://www.regular-expressions.info/examples.html
   # Grabbing HTML Tags
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "one<TAG>two</TAG>three".find(re"<TAG\b[^>]*>(.*?)</TAG>", m)
     check m.boundaries == 3 .. 16
   check("one<TAG>two</TAG>three".findWithCapt(
@@ -1385,7 +1385,7 @@ test "tmisc":
     check(not "127.0.0.999".isMatch(ip))
   # Floating Point Numbers
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "3.14".find(re"^[-+]?[0-9]*\.?[0-9]+$", m)
     check m.boundaries == 0 .. 3
   check "1.602e-19".findWithCapt(
@@ -1400,7 +1400,7 @@ test "tmisc":
     [a-zA-Z]{2,4}
     \b
     """
-    var m: RegexMatch
+    var m = RegexMatch()
     check "john@server.department.company.com".find(email, m)
     check m.boundaries == 0 .. 33
     check(not "john@aol...com".isMatch(email))
@@ -1459,25 +1459,25 @@ test "tmisc":
 
   # Unicode
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "①②③".find(re"①②③", m)
     check m.boundaries == 0 ..< "①②③".len
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "①②③④⑤".find(re"①②③", m)
     check m.boundaries == 0 ..< "①②③".len
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "①②③".find(re"①(②)③", m)
     check m.boundaries == 0 ..< "①②③".len
   check "①②③".findWithCapt(re"①(②)③") == @[@["②"]]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "①②③".find(re"[①②③]*", m)
     check m.boundaries == 0 ..< "①②③".len
   #
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "①②③".find(re"[^④⑤]*", m)
     check m.boundaries == 0 ..< "①②③".len
 
@@ -1502,7 +1502,7 @@ test "tnegative_look_around":
   check "ab".matchWithCapt(re"(\w(?<!c))b") == @[@["a"]]
 
 test "tfull_lookarounds":
-  var m: RegexMatch
+  var m = RegexMatch()
   check match("ab", re"a(?=b)\w")
   check(not match("ab", re"a(?=x)\w"))
   check(not match("ab", re"ab(?=x)"))
@@ -1799,7 +1799,7 @@ test "tpretty_errors":
 
 test "treuse_regex_match":
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "2222".find(re"(22)*", m)
     check m.group(0) == @[0 .. 1, 2 .. 3]
 
@@ -1813,7 +1813,7 @@ test "treuse_regex_match":
     check m.group(0) == @[2 .. 3]
 
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check "foobar".match(re"(?P<foo>(?P<bar>\w*))", m)
     check m.group("foo") == @[0..5]
     check m.group("bar") == @[0..5]
@@ -1833,20 +1833,20 @@ test "tisInitialized":
 test "capturingGroupsNames":
   block:
     let text = "hello world"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<greet>hello) (?P<who>world)", m)
     check m.groupsCount == 2
     for name in @["greet", "who"]:
       check m.groupNames.contains(name)
   block:
     let text = "hello world"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<greet>hello) (?P<who>world)", m)
     check m.group("greet", text) == @["hello"]
     check m.group("who", text) == @["world"]
   block:
     let text = "hello world foo bar"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<greet>hello) (?:(?P<who>[^\s]+)\s?)+", m)
     check m.group("greet", text) == @["hello"]
     let whoGroups = m.group("who", text)
@@ -1854,77 +1854,77 @@ test "capturingGroupsNames":
       check whoGroups.contains(w)
   block:
     let text = "hello world"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<greet>hello) (?P<who>world)", m)
     check m.groupFirstCapture("greet", text) == "hello"
     check m.groupFirstCapture("who", text) == "world"
   block:
     let text = "hello world her"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<greet>hello) (?P<who>world) (?P<who>her)", m)
     check m.groupFirstCapture("greet", text) == "hello"
   block:
     let text = "hello world foo bar"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<greet>hello) (?:(?P<who>[^\s]+)\s?)+", m)
     # "who" captures @["world", "foo", "bar"]
     check m.groupFirstCapture("who", text) == "world"
   block:
     let text = "hello"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<greet>hello)\s?(?P<who>world)?", m)
     check m.groupFirstCapture("greet", text) == "hello"
     check m.groupFirstCapture("who", text) == ""
   block:
     let text = "hello world her"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<greet>hello) (?P<who>world) (?P<who>her)", m)
     check m.groupLastCapture("who", text) == "her"
   block:
     let text = "hello world foo bar"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<greet>hello) (?:(?P<who>[^\s]+)\s?)+", m)
     # "who" captures @["world", "foo", "bar"]
     check m.groupLastCapture("who", text) == "bar"
   block:
     let text = "hello"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(?P<greet>hello)\s?(?P<who>world)?", m)
     check m.groupLastCapture("greet", text) == "hello"
     check m.groupLastCapture("who", text) == ""
   block:
     let text = "hello"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(hello)\s?(world)?", m)
     check m.groupLastCapture(0, text) == "hello"
     check m.groupLastCapture(1, text) == ""
   block:
     let text = ""
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(hello)?\s?(world)?", m)
     check m.groupLastCapture(0, text) == ""
     check m.groupLastCapture(1, text) == ""
   block:
     let text = "hello world foo bar"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(hello) (?:([^\s]+)\s?)+", m)
     # "who" captures @["world", "foo", "bar"]
     check m.groupLastCapture(1, text) == "bar"
   block:
     let text = "hello"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(hello)\s?(world)?", m)
     check m.groupFirstCapture(0, text) == "hello"
     check m.groupFirstCapture(1, text) == ""
   block:
     let text = ""
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(hello)?\s?(world)?", m)
     check m.groupFirstCapture(0, text) == ""
     check m.groupFirstCapture(1, text) == ""
   block:
     let text = "hello world foo bar"
-    var m: RegexMatch
+    var m = RegexMatch()
     check text.match(re"(hello) (?:([^\s]+)\s?)+", m)
     # "who" captures @["world", "foo", "bar"]
     check m.groupFirstCapture(1, text) == "world"
@@ -1932,7 +1932,7 @@ test "capturingGroupsNames":
 # XXX raise a compile error when regex contains unicode
 #     in ascii mode
 test "tflags":
-  var m: RegexMatch
+  var m = RegexMatch()
   #check match("abc", re(r"abc", {reAscii}), m)
   check match("弢弢弢", re"\w{3}", m)
   #check(not match("弢弢弢", re(r"\w{3}", {reAscii}), m))
@@ -1944,7 +1944,7 @@ test "tflags":
   #check(not "%弢弢%".find(re(r"\w{2}", {reAscii}), m))
 
 test "tfindopt":
-  var m: RegexMatch
+  var m = RegexMatch()
   check(not find("bar", re"foo", m))
   check(not find("bar", re"baz", m))
   check "abcd".find(re"bc", m)
@@ -2150,7 +2150,7 @@ test "tfindallopt":
     @[0 .. 10, 14 .. 25]
 
 test "tmisc2":
-  var m: RegexMatch
+  var m = RegexMatch()
   check "one<TAG>two</TAG>tree".find(re"<TAG>.*?</TAG>", m)
   check m.boundaries == 3 .. 16
   check "one<TAG>two</TAG>tree".find(re"<TAG>[\w<>/]*?</TAG>", m)
@@ -2228,7 +2228,7 @@ test "tmisc2":
     m.captures == @[@[0 .. 6, 7 .. 10], @[0 .. 0, 1 .. 1, 2 .. 2], @[4 .. 6, 8 .. 10]]
 
 test "tmisc2_5":
-  var m: RegexMatch
+  var m = RegexMatch()
   check match("abd", re"((ab)c)|((ab)d)", m) and
     m.captures == @[@[], @[], @[0 .. 2], @[0 .. 1]]
   check match("aaa", re"(a*)", m) and
@@ -2291,7 +2291,7 @@ test "tmisc2_6":
     check(not match("1", re1))
 
 test "tmisc3":
-  var m: RegexMatch
+  var m = RegexMatch()
   block:  # issue #61
     const a = "void __mingw_setusermatherr (int (__attribute__((__cdecl__)) *)(struct _exception *));"
     check replace(a, re"__attribute__[ ]*\(\(.*?\)\)([ ,;])", "$1") ==
@@ -2416,7 +2416,7 @@ test "tmisc3":
   check split("foobar", re"o(?=b)") == @["fo", "bar"]
   check split("foobar", re"o(?!b)") == @["f", "obar"]
   block:
-    var m: RegexMatch
+    var m = RegexMatch()
     check find("abcxyz", re"(abc)|\w+", m)
     check m.boundaries == 0 .. 2
     check find("xyzabc", re"(abc)|\w+", m)
@@ -2515,7 +2515,7 @@ test "issue_98":
   check match("1.1", re"(\d+)\.(\d+)(\.(\d+)|)(\.(\d+)|)")
 
 test "issue_101":
-  var m: RegexMatch
+  var m = RegexMatch()
   check match("TXT1/TXT2.1", re"(TXT1)/TXT2()\.(\d+)")
   check match("TXT1/TXT2.1", re"(TXT1)/TXT2(?:)\.(\d+)")
   check match("TXT1/TXT2.1", re"(TXT1)/TXT2(?i:)\.(\d+)")
diff --git a/tests/tests2.nim b/tests/tests2.nim
index 8c7baa2..07a9a61 100644
--- a/tests/tests2.nim
+++ b/tests/tests2.nim
@@ -29,11 +29,11 @@ template expect(exception: typedesc, body: untyped): untyped =
 
 when defined(forceRegexAtRuntime):
   proc isMatch(s: string, pattern: Regex2): bool =
-    var m: RegexMatch2
+    var m = RegexMatch2()
     result = match(s, pattern, m)
 else:
   proc isMatch(s: string, pattern: static Regex2): bool =
-    var m: RegexMatch2
+    var m = RegexMatch2()
     result = match(s, pattern, m)
 
 proc raises(pattern: string): bool =
@@ -50,14 +50,14 @@ proc raisesMsg(pattern: string): string =
     result = getCurrentExceptionMsg()
 
 proc matchWithCapt(s: string, pattern: static Regex2): seq[string] =
-  var m: RegexMatch2
+  var m = RegexMatch2()
   check match(s, pattern, m)
   result.setLen m.captures.len
   for i, bounds in m.captures.pairs:
     result[i] = s[bounds]
 
 proc matchWithBounds(s: string, pattern: static Regex2): seq[Slice[int]] =
-  var m: RegexMatch2
+  var m = RegexMatch2()
   check match(s, pattern, m)
   return m.captures
 
@@ -67,7 +67,7 @@ proc toStrCaptures(m: RegexMatch2, s: string): seq[string] =
     result[i] = s[bounds]
 
 proc findWithCapt(s: string, pattern: Regex2): seq[string] =
-  var m: RegexMatch2
+  var m = RegexMatch2()
   check find(s, pattern, m)
   result = m.toStrCaptures(s)
 
@@ -1041,11 +1041,11 @@ test "tgreediness":
   check "aaa".matchWithCapt(re2"(a){1,}?(a){1,}(a)?") == @["a", "a", ""]
   check "aaa".matchWithCapt(re2"(a){1,}?(a){1,}?(a)?") == @["a", "a", "a"]
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check match("aaaa", re2"(a*?)(a*?)(a*)", m)
     check m.toStrCaptures("aaaa") == @["", "", "aaaa"]
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check match("aaaa", re2"(a*)(a*?)(a*?)", m)
     check m.toStrCaptures("aaaa") == @["aaaa", "", ""]
 
@@ -1072,48 +1072,48 @@ test "tdot_any_matcher":
 
 test "tgroup":
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "foobar".match(re2"(\w*)", m)
     check m.group(0) == 0..5
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "foobar".match(re2"(?P<foo>\w*)", m)
     check m.group(0) == 0..5
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "ab".match(re2"(a)(b)", m)
     check m.group(0) == 0..0
     check m.group(1) == 1..1
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check match("ab", re2"(a)(b)", m)
     check m.toStrCaptures("ab") == @["a", "b"]
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "abc".match(re2"(?P<foo>\w)+", m)
     check m.group("foo") == 2..2
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "abc".match(re2"(\w)+", m)
     check m.group(0) == 2..2
 
 test "tnamed_groups":
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "foobar".match(re2"(?P<foo>\w*)", m)
     check m.group("foo") == 0..5
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "foobar".match(re2"(?P<foo>(?P<bar>\w*))", m)
     check m.group("foo") == 0..5
     check m.group("bar") == 0..5
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "aab".match(re2"(?P<foo>(?P<bar>a)*b)", m)
     check m.group("foo") == 0..2
     check m.group("bar") == 1..1
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "aab".match(re2"((?P<bar>a)*b)", m)
     check m.group("bar") == 1..1
 
@@ -1318,47 +1318,47 @@ test "tescaped_sequences":
 
 test "tfind":
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "abcd".find(re2"bc", m)
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check(not "abcd".find(re2"ac", m))
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "a".find(re2"", m)
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "abcd".find(re2"^abcd$", m)
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "2222".find(re2"(22)*", m)
     check m.group(0) == 2 .. 3
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "abcd".find(re2"(ab)", m)
     check m.group(0) == 0 .. 1
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "abcd".find(re2"(bc)", m)
     check m.group(0) == 1 .. 2
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "abcd".find(re2"(cd)", m)
     check m.group(0) == 2 .. 3
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "abcd".find(re2"bc", m)
     check m.boundaries == 1 .. 2
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "aΪⒶ弢".find(re2"Ϊ", m)
     check m.boundaries == 1 .. 2
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "aΪⒶ弢".find(re2"Ⓐ", m)
     check m.boundaries == 3 .. 5
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "aΪⒶ弢".find(re2"弢", m)
     check m.boundaries == 6 .. 9
 
@@ -1753,17 +1753,17 @@ test "treplace":
 
 test "tmisc":
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "abc".match(re2"[^^]+", m)
     check m.boundaries == 0 .. 2
   check(not "^".isMatch(re2"[^^]+"))
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "kpd".match(re2"[^al-obc]+", m)
     check m.boundaries == 0 .. 2
   check(not "abc".isMatch(re2"[^al-obc]+"))
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "almocb".match(re2"[al-obc]+", m)
     check m.boundaries == 0 .. 5
   check(not "defzx".isMatch(re2"[al-obc]+"))
@@ -1771,7 +1771,7 @@ test "tmisc":
   # From http://www.regular-expressions.info/examples.html
   # Grabbing HTML Tags
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "one<TAG>two</TAG>three".find(re2"<TAG\b[^>]*>(.*?)</TAG>", m)
     check m.boundaries == 3 .. 16
   check("one<TAG>two</TAG>three".findWithCapt(
@@ -1794,7 +1794,7 @@ test "tmisc":
     check(not "127.0.0.999".isMatch(ip))
   # Floating Point Numbers
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "3.14".find(re2"^[-+]?[0-9]*\.?[0-9]+$", m)
     check m.boundaries == 0 .. 3
   check "1.602e-19".findWithCapt(
@@ -1809,7 +1809,7 @@ test "tmisc":
     [a-zA-Z]{2,4}
     \b
     """
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "john@server.department.company.com".find(email, m)
     check m.boundaries == 0 .. 33
     check(not "john@aol...com".isMatch(email))
@@ -1868,25 +1868,25 @@ test "tmisc":
 
   # Unicode
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "①②③".find(re2"①②③", m)
     check m.boundaries == 0 ..< "①②③".len
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "①②③④⑤".find(re2"①②③", m)
     check m.boundaries == 0 ..< "①②③".len
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "①②③".find(re2"①(②)③", m)
     check m.boundaries == 0 ..< "①②③".len
   check "①②③".findWithCapt(re2"①(②)③") == @["②"]
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "①②③".find(re2"[①②③]*", m)
     check m.boundaries == 0 ..< "①②③".len
   #
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "①②③".find(re2"[^④⑤]*", m)
     check m.boundaries == 0 ..< "①②③".len
 
@@ -1911,7 +1911,7 @@ test "tnegative_look_around":
   check "ab".matchWithCapt(re2"(\w(?<!c))b") == @["a"]
 
 test "tfull_lookarounds":
-  var m: RegexMatch2
+  var m = RegexMatch2()
   check match("ab", re2"a(?=b)\w")
   check(not match("ab", re2"a(?=x)\w"))
   check(not match("ab", re2"ab(?=x)"))
@@ -2208,7 +2208,7 @@ test "tpretty_errors":
 
 test "treuse_regex_match":
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "2222".find(re2"(22)*", m)
     check m.group(0) == 2 .. 3
 
@@ -2222,7 +2222,7 @@ test "treuse_regex_match":
     check m.group(0) == 2 .. 3
 
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check "foobar".match(re2"(?P<foo>(?P<bar>\w*))", m)
     check m.group("foo") == 0..5
     check m.group("bar") == 0..5
@@ -2242,61 +2242,61 @@ test "tisInitialized":
 test "capturingGroupsNames":
   block:
     let text = "hello world"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check text.match(re2"(?P<greet>hello) (?P<who>world)", m)
     check m.groupsCount == 2
     for name in @["greet", "who"]:
       check m.groupNames.contains(name)
   block:
     let text = "hello world"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check text.match(re2"(?P<greet>hello) (?P<who>world)", m)
     check m.group("greet", text) == "hello"
     check m.group("who", text) == "world"
   block:
     let text = "hello world foo bar"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check text.match(re2"(?P<greet>hello) (?:(?P<who>[^\s]+)\s?)+", m)
     check m.group("greet", text) == "hello"
     check m.group("who", text) == "bar"
   block:
     let text = "hello world her"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check text.match(re2"(?P<greet>hello) (?P<who>world) (?P<who>her)", m)
     check m.group("who", text) == "her"
   block:
     let text = "hello world foo bar"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check text.match(re2"(?P<greet>hello) (?:(?P<who>[^\s]+)\s?)+", m)
     check m.group("who", text) == "bar"
   block:
     let text = "hello"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check text.match(re2"(?P<greet>hello)\s?(?P<who>world)?", m)
     check m.group("greet", text) == "hello"
     check m.group("who", text) == ""
   block:
     let text = "hello"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check text.match(re2"(hello)\s?(world)?", m)
     check m.group(0, text) == "hello"
     check m.group(1, text) == ""
   block:
     let text = ""
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check text.match(re2"(hello)?\s?(world)?", m)
     check m.group(0, text) == ""
     check m.group(1, text) == ""
   block:
     let text = "hello world foo bar"
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check text.match(re2"(hello) (?:([^\s]+)\s?)+", m)
     check m.group(1, text) == "bar"
 
 # XXX raise a compile error when regex contains unicode
 #     in ascii mode
 test "tflags":
-  var m: RegexMatch2
+  var m = RegexMatch2()
   #check match("abc", re2(r"abc", {reAscii}), m)
   check match("弢弢弢", re2"\w{3}", m)
   #check(not match("弢弢弢", re2(r"\w{3}", {reAscii}), m))
@@ -2308,7 +2308,7 @@ test "tflags":
   #check(not "%弢弢%".find(re2(r"\w{2}", {reAscii}), m))
 
 test "tfindopt":
-  var m: RegexMatch2
+  var m = RegexMatch2()
   check(not find("bar", re2"foo", m))
   check(not find("bar", re2"baz", m))
   check "abcd".find(re2"bc", m)
@@ -2514,7 +2514,7 @@ test "tfindallopt":
     @[0 .. 10, 14 .. 25]
 
 test "tmisc2":
-  var m: RegexMatch2
+  var m = RegexMatch2()
   check "one<TAG>two</TAG>tree".find(re2"<TAG>.*?</TAG>", m)
   check m.boundaries == 3 .. 16
   check "one<TAG>two</TAG>tree".find(re2"<TAG>[\w<>/]*?</TAG>", m)
@@ -2589,7 +2589,7 @@ test "tmisc2":
     m.captures == @[7 .. 10, 2 .. 2, 8 .. 10]
 
 test "tmisc2_5":
-  var m: RegexMatch2
+  var m = RegexMatch2()
   check match("abd", re2"((ab)c)|((ab)d)", m) and
     m.captures == @[nonCapture, nonCapture, 0 .. 2, 0 .. 1]
   check match("aaa", re2"(a*)", m) and
@@ -2652,7 +2652,7 @@ test "tmisc2_6":
     check(not match("1", re1))
 
 test "tmisc3":
-  var m: RegexMatch2
+  var m = RegexMatch2()
   block:  # issue #61
     const a = "void __mingw_setusermatherr (int (__attribute__((__cdecl__)) *)(struct _exception *));"
     check replace(a, re2"__attribute__[ ]*\(\(.*?\)\)([ ,;])", "$1") ==
@@ -2777,7 +2777,7 @@ test "tmisc3":
   check split("foobar", re2"o(?=b)") == @["fo", "bar"]
   check split("foobar", re2"o(?!b)") == @["f", "obar"]
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check find("abcxyz", re2"(abc)|\w+", m)
     check m.boundaries == 0 .. 2
     check find("xyzabc", re2"(abc)|\w+", m)
@@ -2990,7 +2990,7 @@ test "issue_98":
   check match("1.1", re2"(\d+)\.(\d+)(\.(\d+)|)(\.(\d+)|)")
 
 test "issue_101":
-  var m: RegexMatch2
+  var m = RegexMatch2()
   check match("TXT1/TXT2.1", re2"(TXT1)/TXT2()\.(\d+)")
   check match("TXT1/TXT2.1", re2"(TXT1)/TXT2(?:)\.(\d+)")
   check match("TXT1/TXT2.1", re2"(TXT1)/TXT2(?i:)\.(\d+)")
@@ -3011,7 +3011,7 @@ test "issue_101":
   check(not match("A", re2"(?xi:(?xi)     )a"))
 
 test "tlookaround_captures":
-  var m: RegexMatch2
+  var m = RegexMatch2()
   check match("aaab", re2"((\w+)|a(a+)b(?<=^(a+)(b)))", m) and
     m.captures == @[0 .. 3, 0 .. 3, nonCapture, nonCapture, nonCapture]
   check match("aaab", re2"a(a+)b(?<=^(a+)(b))", m) and
@@ -3074,7 +3074,7 @@ test "tverifyutf8":
   check raisesMsg("\xff") == "Invalid utf-8 regex"
   raisesInvalidUtf8 match("\xff", re2"abc")
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     raisesInvalidUtf8 match("\xff", re2"abc", m)
   raisesInvalidUtf8 findAll("\xff", re2"abc")
   raisesInvalidUtf8 findAllBounds("\xff", re2"abc")
@@ -3170,7 +3170,7 @@ when not defined(js) or NimMajor >= 2:
       check replace("ΪⒶ弢ΪⒶ弢x", re2(r"ΪⒶ弢\w", flags), "abc") == "ΪⒶ弢abc"
       check replace("ΪⒶ弢ΪⒶ弢x", re2(r"(?u)ΪⒶ弢\w", flags), "abc") == "abc\xaaⒶ弢x"
     block:
-      var m: RegexMatch2
+      var m = RegexMatch2()
       check match("a", re2(r"a", flags)) and
         m.groupsCount == 0
       check match("\x02\xF8\x95", re2(r"\x{2F895}", flags)) and 
@@ -3287,7 +3287,7 @@ test "tvarflags":
     var flags = {regexDotAll}
     check match("a\L", re2(r"a.", flags))
   block:
-    var m: RegexMatch2
+    var m = RegexMatch2()
     check match("aa", re2(r"(a*)(a*)", {regexUngreedy}), m) and
       m.captures == @[0 .. -1, 0 .. 1]
     check match("aa", re2"(?U)(a*)(a*)", m) and