diff --git a/compiler/condsyms.nim b/compiler/condsyms.nim
index aecbde66e4..297b865b22 100644
--- a/compiler/condsyms.nim
+++ b/compiler/condsyms.nim
@@ -90,3 +90,4 @@ proc initDefines*() =
   defineSymbol("nimnode")
   defineSymbol("nimnomagic64")
   defineSymbol("nimvarargstyped")
+  defineSymbol("nimtypedescfixed")
diff --git a/compiler/lambdalifting.nim b/compiler/lambdalifting.nim
index d11776cf6d..c669fc7458 100644
--- a/compiler/lambdalifting.nim
+++ b/compiler/lambdalifting.nim
@@ -184,7 +184,7 @@ proc addHiddenParam(routine: PSym, param: PSym) =
   var params = routine.ast.sons[paramsPos]
   # -1 is correct here as param.position is 0 based but we have at position 0
   # some nkEffect node:
-  param.position = params.len-1
+  param.position = routine.typ.n.len-1
   addSon(params, newSymNode(param))
   incl(routine.typ.flags, tfCapturesEnv)
   assert sfFromGeneric in param.flags
diff --git a/compiler/semdestruct.nim b/compiler/semdestruct.nim
index aaab49a101..af671f6e00 100644
--- a/compiler/semdestruct.nim
+++ b/compiler/semdestruct.nim
@@ -177,6 +177,15 @@ proc instantiateDestructor(c: PContext, typ: PType): PType =
   else:
     return nil
 
+proc createDestructorCall(c: PContext, s: PSym): PNode =
+  let varTyp = s.typ
+  if varTyp == nil or sfGlobal in s.flags: return
+  let destructableT = instantiateDestructor(c, varTyp)
+  if destructableT != nil:
+    let call = semStmt(c, newNode(nkCall, s.info, @[
+      useSym(destructableT.destructor), useSym(s)]))
+    result = newNode(nkDefer, s.info, @[call])
+
 proc insertDestructors(c: PContext,
                        varSection: PNode): tuple[outer, inner: PNode] =
   # Accepts a var or let section.
diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index b4308def3c..0e9b9ae5f1 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -2259,7 +2259,10 @@ proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}): PNode =
   of nkStaticStmt:
     result = semStaticStmt(c, n)
   of nkDefer:
-    localError(n.info, errGenerated, "'defer' not allowed in this context")
+    n.sons[0] = semExpr(c, n.sons[0])
+    if not n.sons[0].typ.isEmptyType and not implicitlyDiscardable(n.sons[0]):
+      localError(n.info, errGenerated, "'defer' takes a 'void' expression")
+    #localError(n.info, errGenerated, "'defer' not allowed in this context")
   else:
     localError(n.info, errInvalidExpressionX,
                renderTree(n, {renderNoComments}))
diff --git a/compiler/semgnrc.nim b/compiler/semgnrc.nim
index db910600bd..205af36a85 100644
--- a/compiler/semgnrc.nim
+++ b/compiler/semgnrc.nim
@@ -39,9 +39,9 @@ type
 proc semGenericStmt(c: PContext, n: PNode,
                     flags: TSemGenericFlags, ctx: var GenericCtx): PNode
 
-proc semGenericStmtScope(c: PContext, n: PNode, 
+proc semGenericStmtScope(c: PContext, n: PNode,
                          flags: TSemGenericFlags,
-                         ctx: var GenericCtx): PNode = 
+                         ctx: var GenericCtx): PNode =
   openScope(c)
   result = semGenericStmt(c, n, flags, ctx)
   closeScope(c)
@@ -73,7 +73,7 @@ proc semGenericStmtSymbol(c: PContext, n: PNode, s: PSym,
       result = semGenericStmt(c, result, {}, ctx)
     else:
       result = symChoice(c, n, s, scOpen)
-  of skGenericParam: 
+  of skGenericParam:
     if s.typ != nil and s.typ.kind == tyStatic:
       if s.typ.n != nil:
         result = s.typ.n
@@ -85,18 +85,18 @@ proc semGenericStmtSymbol(c: PContext, n: PNode, s: PSym,
   of skParam:
     result = n
     styleCheckUse(n.info, s)
-  of skType: 
+  of skType:
     if (s.typ != nil) and
        (s.typ.flags * {tfGenericTypeParam, tfImplicitTypeParam} == {}):
       result = newSymNodeTypeDesc(s, n.info)
-    else: 
+    else:
       result = n
     styleCheckUse(n.info, s)
   else:
     result = newSymNode(s, n.info)
     styleCheckUse(n.info, s)
 
-proc lookup(c: PContext, n: PNode, flags: TSemGenericFlags, 
+proc lookup(c: PContext, n: PNode, flags: TSemGenericFlags,
             ctx: var GenericCtx): PNode =
   result = n
   let ident = considerQuotedIdent(n)
@@ -118,13 +118,13 @@ proc newDot(n, b: PNode): PNode =
   result.add(n.sons[0])
   result.add(b)
 
-proc fuzzyLookup(c: PContext, n: PNode, flags: TSemGenericFlags, 
+proc fuzzyLookup(c: PContext, n: PNode, flags: TSemGenericFlags,
                  ctx: var GenericCtx; isMacro: var bool): PNode =
   assert n.kind == nkDotExpr
   semIdeForTemplateOrGenericCheck(n, ctx.cursorInBody)
 
   let luf = if withinMixin notin flags: {checkUndeclared} else: {}
-  
+
   var s = qualifiedLookUp(c, n, luf)
   if s != nil:
     result = semGenericStmtSymbol(c, n, s, ctx)
@@ -141,18 +141,20 @@ proc fuzzyLookup(c: PContext, n: PNode, flags: TSemGenericFlags,
       elif s.name.id in ctx.toMixin:
         result = newDot(result, symChoice(c, n, s, scForceOpen))
       else:
-        let sym = semGenericStmtSymbol(c, n, s, ctx)
-        if sym.kind == nkSym:
-          result = newDot(result, symChoice(c, n, s, scForceOpen))
+        let syms = semGenericStmtSymbol(c, n, s, ctx)
+        if syms.kind == nkSym:
+          let choice = symChoice(c, n, s, scForceOpen)
+          choice.kind = nkClosedSymChoice
+          result = newDot(result, choice)
         else:
-          result = newDot(result, sym)
+          result = newDot(result, syms)
 
 proc addTempDecl(c: PContext; n: PNode; kind: TSymKind) =
   let s = newSymS(skUnknown, getIdentNode(n), c)
   addPrelimDecl(c, s)
   styleCheckDef(n.info, s, kind)
 
-proc semGenericStmt(c: PContext, n: PNode, 
+proc semGenericStmt(c: PContext, n: PNode,
                     flags: TSemGenericFlags, ctx: var GenericCtx): PNode =
   result = n
   #if gCmd == cmdIdeTools: suggestStmt(c, n)
@@ -181,16 +183,16 @@ proc semGenericStmt(c: PContext, n: PNode,
     result = semGenericStmt(c, n.sons[0], flags+{withinBind}, ctx)
   of nkMixinStmt:
     result = semMixinStmt(c, n, ctx.toMixin)
-  of nkCall, nkHiddenCallConv, nkInfix, nkPrefix, nkCommand, nkCallStrLit: 
+  of nkCall, nkHiddenCallConv, nkInfix, nkPrefix, nkCommand, nkCallStrLit:
     # check if it is an expression macro:
     checkMinSonsLen(n, 1)
     let fn = n.sons[0]
     var s = qualifiedLookUp(c, fn, {})
     if s == nil and withinMixin notin flags and
-        fn.kind in {nkIdent, nkAccQuoted} and 
+        fn.kind in {nkIdent, nkAccQuoted} and
         considerQuotedIdent(fn).id notin ctx.toMixin:
       localError(n.info, errUndeclaredIdentifier, fn.renderTree)
-    
+
     var first = 0
     var mixinContext = false
     if s != nil:
@@ -220,7 +222,7 @@ proc semGenericStmt(c: PContext, n: PNode,
         # we need to put the ``c`` in ``t(c)`` in a mixin context to prevent
         # the famous "undeclared identifier: it" bug:
         mixinContext = true
-      of skUnknown, skParam: 
+      of skUnknown, skParam:
         # Leave it as an identifier.
         discard
       of skProc, skMethod, skIterators, skConverter:
@@ -230,9 +232,9 @@ proc semGenericStmt(c: PContext, n: PNode,
         result.sons[0] = newSymNodeTypeDesc(s, fn.info)
         styleCheckUse(fn.info, s)
         first = 1
-      of skType: 
+      of skType:
         # bad hack for generics:
-        if (s.typ != nil) and (s.typ.kind != tyGenericParam): 
+        if (s.typ != nil) and (s.typ.kind != tyGenericParam):
           result.sons[0] = newSymNodeTypeDesc(s, fn.info)
           styleCheckUse(fn.info, s)
           first = 1
@@ -244,34 +246,34 @@ proc semGenericStmt(c: PContext, n: PNode,
       result.sons[0] = fuzzyLookup(c, fn, flags, ctx, mixinContext)
       first = 1
     # Consider 'when declared(globalsSlot): ThreadVarSetValue(globalsSlot, ...)'
-    # in threads.nim: the subtle preprocessing here binds 'globalsSlot' which 
+    # in threads.nim: the subtle preprocessing here binds 'globalsSlot' which
     # is not exported and yet the generic 'threadProcWrapper' works correctly.
     let flags = if mixinContext: flags+{withinMixin} else: flags
     for i in countup(first, sonsLen(result) - 1):
       result.sons[i] = semGenericStmt(c, result.sons[i], flags, ctx)
-  of nkIfStmt: 
-    for i in countup(0, sonsLen(n)-1): 
+  of nkIfStmt:
+    for i in countup(0, sonsLen(n)-1):
       n.sons[i] = semGenericStmtScope(c, n.sons[i], flags, ctx)
   of nkWhenStmt:
     for i in countup(0, sonsLen(n)-1):
       n.sons[i] = semGenericStmt(c, n.sons[i], flags+{withinMixin}, ctx)
-  of nkWhileStmt: 
+  of nkWhileStmt:
     openScope(c)
-    for i in countup(0, sonsLen(n)-1): 
+    for i in countup(0, sonsLen(n)-1):
       n.sons[i] = semGenericStmt(c, n.sons[i], flags, ctx)
     closeScope(c)
-  of nkCaseStmt: 
+  of nkCaseStmt:
     openScope(c)
     n.sons[0] = semGenericStmt(c, n.sons[0], flags, ctx)
-    for i in countup(1, sonsLen(n)-1): 
+    for i in countup(1, sonsLen(n)-1):
       var a = n.sons[i]
       checkMinSonsLen(a, 1)
       var L = sonsLen(a)
-      for j in countup(0, L-2): 
+      for j in countup(0, L-2):
         a.sons[j] = semGenericStmt(c, a.sons[j], flags, ctx)
       a.sons[L - 1] = semGenericStmtScope(c, a.sons[L-1], flags, ctx)
     closeScope(c)
-  of nkForStmt, nkParForStmt: 
+  of nkForStmt, nkParForStmt:
     var L = sonsLen(n)
     openScope(c)
     n.sons[L - 2] = semGenericStmt(c, n.sons[L-2], flags, ctx)
@@ -279,27 +281,27 @@ proc semGenericStmt(c: PContext, n: PNode,
       addTempDecl(c, n.sons[i], skForVar)
     n.sons[L - 1] = semGenericStmt(c, n.sons[L-1], flags, ctx)
     closeScope(c)
-  of nkBlockStmt, nkBlockExpr, nkBlockType: 
+  of nkBlockStmt, nkBlockExpr, nkBlockType:
     checkSonsLen(n, 2)
     openScope(c)
-    if n.sons[0].kind != nkEmpty: 
+    if n.sons[0].kind != nkEmpty:
       addTempDecl(c, n.sons[0], skLabel)
     n.sons[1] = semGenericStmt(c, n.sons[1], flags, ctx)
     closeScope(c)
-  of nkTryStmt: 
+  of nkTryStmt:
     checkMinSonsLen(n, 2)
     n.sons[0] = semGenericStmtScope(c, n.sons[0], flags, ctx)
-    for i in countup(1, sonsLen(n)-1): 
+    for i in countup(1, sonsLen(n)-1):
       var a = n.sons[i]
       checkMinSonsLen(a, 1)
       var L = sonsLen(a)
-      for j in countup(0, L-2): 
+      for j in countup(0, L-2):
         a.sons[j] = semGenericStmt(c, a.sons[j], flags+{withinTypeDesc}, ctx)
       a.sons[L-1] = semGenericStmtScope(c, a.sons[L-1], flags, ctx)
-  of nkVarSection, nkLetSection: 
-    for i in countup(0, sonsLen(n) - 1): 
+  of nkVarSection, nkLetSection:
+    for i in countup(0, sonsLen(n) - 1):
       var a = n.sons[i]
-      if a.kind == nkCommentStmt: continue 
+      if a.kind == nkCommentStmt: continue
       if (a.kind != nkIdentDefs) and (a.kind != nkVarTuple): illFormedAst(a)
       checkMinSonsLen(a, 3)
       var L = sonsLen(a)
@@ -307,49 +309,49 @@ proc semGenericStmt(c: PContext, n: PNode,
       a.sons[L-1] = semGenericStmt(c, a.sons[L-1], flags, ctx)
       for j in countup(0, L-3):
         addTempDecl(c, getIdentNode(a.sons[j]), skVar)
-  of nkGenericParams: 
-    for i in countup(0, sonsLen(n) - 1): 
+  of nkGenericParams:
+    for i in countup(0, sonsLen(n) - 1):
       var a = n.sons[i]
       if (a.kind != nkIdentDefs): illFormedAst(a)
       checkMinSonsLen(a, 3)
       var L = sonsLen(a)
-      a.sons[L-2] = semGenericStmt(c, a.sons[L-2], flags+{withinTypeDesc}, ctx) 
-      # do not perform symbol lookup for default expressions 
-      for j in countup(0, L-3): 
+      a.sons[L-2] = semGenericStmt(c, a.sons[L-2], flags+{withinTypeDesc}, ctx)
+      # do not perform symbol lookup for default expressions
+      for j in countup(0, L-3):
         addTempDecl(c, getIdentNode(a.sons[j]), skType)
-  of nkConstSection: 
-    for i in countup(0, sonsLen(n) - 1): 
+  of nkConstSection:
+    for i in countup(0, sonsLen(n) - 1):
       var a = n.sons[i]
-      if a.kind == nkCommentStmt: continue 
+      if a.kind == nkCommentStmt: continue
       if (a.kind != nkConstDef): illFormedAst(a)
       checkSonsLen(a, 3)
       addTempDecl(c, getIdentNode(a.sons[0]), skConst)
       a.sons[1] = semGenericStmt(c, a.sons[1], flags+{withinTypeDesc}, ctx)
       a.sons[2] = semGenericStmt(c, a.sons[2], flags, ctx)
   of nkTypeSection:
-    for i in countup(0, sonsLen(n) - 1): 
+    for i in countup(0, sonsLen(n) - 1):
       var a = n.sons[i]
-      if a.kind == nkCommentStmt: continue 
+      if a.kind == nkCommentStmt: continue
       if (a.kind != nkTypeDef): illFormedAst(a)
       checkSonsLen(a, 3)
       addTempDecl(c, getIdentNode(a.sons[0]), skType)
-    for i in countup(0, sonsLen(n) - 1): 
+    for i in countup(0, sonsLen(n) - 1):
       var a = n.sons[i]
-      if a.kind == nkCommentStmt: continue 
+      if a.kind == nkCommentStmt: continue
       if (a.kind != nkTypeDef): illFormedAst(a)
       checkSonsLen(a, 3)
-      if a.sons[1].kind != nkEmpty: 
+      if a.sons[1].kind != nkEmpty:
         openScope(c)
         a.sons[1] = semGenericStmt(c, a.sons[1], flags, ctx)
         a.sons[2] = semGenericStmt(c, a.sons[2], flags+{withinTypeDesc}, ctx)
         closeScope(c)
-      else: 
+      else:
         a.sons[2] = semGenericStmt(c, a.sons[2], flags+{withinTypeDesc}, ctx)
-  of nkEnumTy: 
+  of nkEnumTy:
     if n.sonsLen > 0:
-      if n.sons[0].kind != nkEmpty: 
+      if n.sons[0].kind != nkEmpty:
         n.sons[0] = semGenericStmt(c, n.sons[0], flags+{withinTypeDesc}, ctx)
-      for i in countup(1, sonsLen(n) - 1): 
+      for i in countup(1, sonsLen(n) - 1):
         var a: PNode
         case n.sons[i].kind
         of nkEnumFieldDef: a = n.sons[i].sons[0]
@@ -360,26 +362,26 @@ proc semGenericStmt(c: PContext, n: PNode,
     discard
   of nkFormalParams:
     checkMinSonsLen(n, 1)
-    if n.sons[0].kind != nkEmpty: 
+    if n.sons[0].kind != nkEmpty:
       n.sons[0] = semGenericStmt(c, n.sons[0], flags+{withinTypeDesc}, ctx)
-    for i in countup(1, sonsLen(n) - 1): 
+    for i in countup(1, sonsLen(n) - 1):
       var a = n.sons[i]
       if (a.kind != nkIdentDefs): illFormedAst(a)
       checkMinSonsLen(a, 3)
       var L = sonsLen(a)
       a.sons[L-2] = semGenericStmt(c, a.sons[L-2], flags+{withinTypeDesc}, ctx)
       a.sons[L-1] = semGenericStmt(c, a.sons[L-1], flags, ctx)
-      for j in countup(0, L-3): 
+      for j in countup(0, L-3):
         addTempDecl(c, getIdentNode(a.sons[j]), skParam)
-  of nkProcDef, nkMethodDef, nkConverterDef, nkMacroDef, nkTemplateDef, 
-     nkIteratorDef, nkLambdaKinds: 
+  of nkProcDef, nkMethodDef, nkConverterDef, nkMacroDef, nkTemplateDef,
+     nkIteratorDef, nkLambdaKinds:
     checkSonsLen(n, bodyPos + 1)
     if n.sons[namePos].kind != nkEmpty:
       addTempDecl(c, getIdentNode(n.sons[0]), skProc)
     openScope(c)
-    n.sons[genericParamsPos] = semGenericStmt(c, n.sons[genericParamsPos], 
+    n.sons[genericParamsPos] = semGenericStmt(c, n.sons[genericParamsPos],
                                               flags, ctx)
-    if n.sons[paramsPos].kind != nkEmpty: 
+    if n.sons[paramsPos].kind != nkEmpty:
       if n.sons[paramsPos].sons[0].kind != nkEmpty:
         addPrelimDecl(c, newSym(skUnknown, getIdent("result"), nil, n.info))
       n.sons[paramsPos] = semGenericStmt(c, n.sons[paramsPos], flags, ctx)
@@ -394,7 +396,7 @@ proc semGenericStmt(c: PContext, n: PNode,
     checkMinSonsLen(n, 2)
     result.sons[1] = semGenericStmt(c, n.sons[1], flags, ctx)
   else:
-    for i in countup(0, sonsLen(n) - 1): 
+    for i in countup(0, sonsLen(n) - 1):
       result.sons[i] = semGenericStmt(c, n.sons[i], flags, ctx)
 
 proc semGenericStmt(c: PContext, n: PNode): PNode =
diff --git a/compiler/semstmts.nim b/compiler/semstmts.nim
index 84a09a7e63..3d9363d773 100644
--- a/compiler/semstmts.nim
+++ b/compiler/semstmts.nim
@@ -369,6 +369,15 @@ proc addToVarSection(c: PContext; result: var PNode; orig, identDefs: PNode) =
   else:
     result.add identDefs
 
+proc addDefer(c: PContext; result: var PNode; s: PSym) =
+  let deferDestructorCall = createDestructorCall(c, s)
+  if deferDestructorCall != nil:
+    if result.kind != nkStmtList:
+      let oldResult = result
+      result = newNodeI(nkStmtList, result.info)
+      result.add oldResult
+    result.add deferDestructorCall
+
 proc isDiscardUnderscore(v: PSym): bool =
   if v.name.s == "_":
     v.flags.incl(sfGenSym)
@@ -469,6 +478,7 @@ proc semVarOrLet(c: PContext, n: PNode, symkind: TSymKind): PNode =
         if def.kind == nkPar: v.ast = def[j]
         v.typ = tup.sons[j]
         b.sons[j] = newSymNode(v)
+      addDefer(c, result, v)
       checkNilable(v)
       if sfCompileTime in v.flags: hasCompileTime = true
   if hasCompileTime: vm.setupCompileTimeVar(c.module, result)
@@ -1371,7 +1381,7 @@ proc semStmtList(c: PContext, n: PNode, flags: TExprFlags): PNode =
   for i in countup(0, length - 1):
     let k = n.sons[i].kind
     case k
-    of nkFinally, nkExceptBranch, nkDefer:
+    of nkFinally, nkExceptBranch:
       # stand-alone finally and except blocks are
       # transformed into regular try blocks:
       #
@@ -1424,21 +1434,13 @@ proc semStmtList(c: PContext, n: PNode, flags: TExprFlags): PNode =
         n.typ = n.sons[i].typ
         if not isEmptyType(n.typ): n.kind = nkStmtListExpr
       case n.sons[i].kind
-      of nkVarSection, nkLetSection:
-        let (outer, inner) = insertDestructors(c, n.sons[i])
-        if outer != nil:
-          n.sons[i] = outer
-          var rest = newNode(nkStmtList, n.info, n.sons[i+1 .. length-1])
-          inner.addSon(semStmtList(c, rest, flags))
-          n.sons.setLen(i+1)
-          return
       of LastBlockStmts:
         for j in countup(i + 1, length - 1):
           case n.sons[j].kind
           of nkPragma, nkCommentStmt, nkNilLit, nkEmpty: discard
           else: localError(n.sons[j].info, errStmtInvalidAfterReturn)
       else: discard
-  if result.len == 1:
+  if result.len == 1 and result.sons[0].kind != nkDefer:
     result = result.sons[0]
   when defined(nimfix):
     if result.kind == nkCommentStmt and not result.comment.isNil and
diff --git a/compiler/semtempl.nim b/compiler/semtempl.nim
index a138981b7d..4d1eae48f2 100644
--- a/compiler/semtempl.nim
+++ b/compiler/semtempl.nim
@@ -184,10 +184,25 @@ proc addLocalDecl(c: var TemplCtx, n: var PNode, k: TSymKind) =
   else:
     let ident = getIdentNode(c, n)
     if not isTemplParam(c, ident):
-      let local = newGenSym(k, ident, c)
-      addPrelimDecl(c.c, local)
-      styleCheckDef(n.info, local)
-      replaceIdentBySym(n, newSymNode(local, n.info))
+      # fix #2670, consider:
+      #
+      # when b:
+      #    var a = "hi"
+      # else:
+      #    var a = 5
+      # echo a
+      #
+      # We need to ensure that both 'a' produce the same gensym'ed symbol.
+      # So we need only check the *current* scope.
+      let s = localSearchInScope(c.c, considerQuotedIdent ident)
+      if s != nil and s.owner == c.owner and sfGenSym in s.flags:
+        styleCheckUse(n.info, s)
+        replaceIdentBySym(n, newSymNode(s, n.info))
+      else:
+        let local = newGenSym(k, ident, c)
+        addPrelimDecl(c.c, local)
+        styleCheckDef(n.info, local)
+        replaceIdentBySym(n, newSymNode(local, n.info))
     else:
       replaceIdentBySym(n, ident)
 
diff --git a/compiler/transf.nim b/compiler/transf.nim
index dddbd51c41..5c7472a39c 100644
--- a/compiler/transf.nim
+++ b/compiler/transf.nim
@@ -16,6 +16,7 @@
 # * converts "continue" to "break"; disambiguates "break"
 # * introduces method dispatchers
 # * performs lambda lifting for closure support
+# * transforms 'defer' into a 'try finally' statement
 
 import
   intsets, strutils, lists, options, ast, astalgo, trees, treetab, msgs, os,
@@ -44,6 +45,7 @@ type
     inlining: int            # > 0 if we are in inlining context (copy vars)
     nestedProcs: int         # > 0 if we are in a nested proc
     contSyms, breakSyms: seq[PSym]  # to transform 'continue' and 'break'
+    deferDetected: bool
   PTransf = ref TTransfContext
 
 proc newTransNode(a: PNode): PTransNode {.inline.} =
@@ -680,6 +682,14 @@ proc commonOptimizations*(c: PSym, n: PNode): PNode =
       result = n
 
 proc transform(c: PTransf, n: PNode): PTransNode =
+  when false:
+    var oldDeferAnchor: PNode
+    if n.kind in {nkElifBranch, nkOfBranch, nkExceptBranch, nkElifExpr,
+                  nkElseExpr, nkElse, nkForStmt, nkWhileStmt, nkFinally,
+                  nkBlockStmt, nkBlockExpr}:
+      oldDeferAnchor = c.deferAnchor
+      c.deferAnchor = n
+
   case n.kind
   of nkSym:
     result = transformSym(c, n)
@@ -712,13 +722,36 @@ proc transform(c: PTransf, n: PNode): PTransNode =
     result = transformFor(c, n)
   of nkParForStmt:
     result = transformSons(c, n)
-  of nkCaseStmt: result = transformCase(c, n)
+  of nkCaseStmt:
+    result = transformCase(c, n)
+  of nkWhileStmt: result = transformWhile(c, n)
+  of nkBlockStmt, nkBlockExpr:
+    result = transformBlock(c, n)
+  of nkDefer:
+    c.deferDetected = true
+    result = transformSons(c, n)
+    when false:
+      let deferPart = newNodeI(nkFinally, n.info)
+      deferPart.add n.sons[0]
+      let tryStmt = newNodeI(nkTryStmt, n.info)
+      if c.deferAnchor.isNil:
+        tryStmt.add c.root
+        c.root = tryStmt
+        result = PTransNode(tryStmt)
+      else:
+        # modify the corresponding *action*, don't rely on nkStmtList:
+        let L = c.deferAnchor.len-1
+        tryStmt.add c.deferAnchor.sons[L]
+        c.deferAnchor.sons[L] = tryStmt
+        result = newTransNode(nkCommentStmt, n.info, 0)
+      tryStmt.addSon(deferPart)
+      # disable the original 'defer' statement:
+      n.kind = nkCommentStmt
   of nkContinueStmt:
     result = PTransNode(newNodeI(nkBreakStmt, n.info))
     var labl = c.contSyms[c.contSyms.high]
     add(result, PTransNode(newSymNode(labl)))
   of nkBreakStmt: result = transformBreak(c, n)
-  of nkWhileStmt: result = transformWhile(c, n)
   of nkCallKinds:
     result = transformCall(c, n)
   of nkAddr, nkHiddenAddr:
@@ -754,8 +787,6 @@ proc transform(c: PTransf, n: PNode): PTransNode =
       result = transformYield(c, n)
     else:
       result = transformSons(c, n)
-  of nkBlockStmt, nkBlockExpr:
-    result = transformBlock(c, n)
   of nkIdentDefs, nkConstDef:
     result = transformSons(c, n)
     # XXX comment handling really sucks:
@@ -764,6 +795,8 @@ proc transform(c: PTransf, n: PNode): PTransNode =
   of nkClosure: return PTransNode(n)
   else:
     result = transformSons(c, n)
+  when false:
+    if oldDeferAnchor != nil: c.deferAnchor = oldDeferAnchor
   var cnst = getConstExpr(c.module, PNode(result))
   # we inline constants if they are not complex constants:
   if cnst != nil and not dontInlineConstant(n, cnst):
@@ -785,12 +818,52 @@ proc openTransf(module: PSym, filename: string): PTransf =
   result.breakSyms = @[]
   result.module = module
 
+proc flattenStmts(n: PNode) =
+  var goOn = true
+  while goOn:
+    goOn = false
+    for i in 0..<n.len:
+      let it = n[i]
+      if it.kind in {nkStmtList, nkStmtListExpr}:
+        n.sons[i..i] = it.sons[0..<it.len]
+        goOn = true
+
+proc liftDeferAux(n: PNode) =
+  if n.kind in {nkStmtList, nkStmtListExpr}:
+    flattenStmts(n)
+    var goOn = true
+    while goOn:
+      goOn = false
+      let last = n.len-1
+      for i in 0..last:
+        if n.sons[i].kind == nkDefer:
+          let deferPart = newNodeI(nkFinally, n.sons[i].info)
+          deferPart.add n.sons[i].sons[0]
+          var tryStmt = newNodeI(nkTryStmt, n.sons[i].info)
+          var body = newNodeI(n.kind, n.sons[i].info)
+          if i < last:
+            body.sons = n.sons[(i+1)..last]
+          tryStmt.addSon(body)
+          tryStmt.addSon(deferPart)
+          n.sons[i] = tryStmt
+          n.sons.setLen(i+1)
+          n.typ = n.sons[i].typ
+          goOn = true
+          break
+  for i in 0..n.safeLen-1:
+    liftDeferAux(n.sons[i])
+
+template liftDefer(c, root) =
+  if c.deferDetected:
+    liftDeferAux(root)
+
 proc transformBody*(module: PSym, n: PNode, prc: PSym): PNode =
   if nfTransf in n.flags or prc.kind in {skTemplate}:
     result = n
   else:
     var c = openTransf(module, "")
     result = processTransf(c, n, prc)
+    liftDefer(c, result)
     result = liftLambdas(prc, result)
     #if prc.kind == skClosureIterator:
     #  result = lambdalifting.liftIterator(prc, result)
@@ -805,6 +878,7 @@ proc transformStmt*(module: PSym, n: PNode): PNode =
   else:
     var c = openTransf(module, "")
     result = processTransf(c, n, module)
+    liftDefer(c, result)
     result = liftLambdasForTopLevel(module, result)
     incl(result.flags, nfTransf)
     when useEffectSystem: trackTopLevelStmt(module, result)
@@ -815,4 +889,5 @@ proc transformExpr*(module: PSym, n: PNode): PNode =
   else:
     var c = openTransf(module, "")
     result = processTransf(c, n, module)
+    liftDefer(c, result)
     incl(result.flags, nfTransf)
diff --git a/compiler/vm.nim b/compiler/vm.nim
index d7495d77f1..e381af97fb 100644
--- a/compiler/vm.nim
+++ b/compiler/vm.nim
@@ -432,7 +432,7 @@ proc rawExecute(c: PCtx, start: int, tos: PStackFrame): TFullReg =
         assert regs[rb].kind == rkNode
         let nb = regs[rb].node
         case nb.kind
-        of nkCharLit..nkInt64Lit:
+        of nkCharLit..nkUInt64Lit:
           ensureKind(rkInt)
           regs[ra].intVal = nb.intVal
         of nkFloatLit..nkFloat64Lit:
diff --git a/contributing.rst b/contributing.rst
index e6d34dcb05..65b0d0975e 100644
--- a/contributing.rst
+++ b/contributing.rst
@@ -66,12 +66,14 @@ Running tests
 You can run the tests with
 
 ::
+
   ./koch tests
 
 which will run a good subset of tests. Some tests may fail. If you
 only want to see the output of failing tests, go for
 
 ::
+
   ./koch tests --failing all
 
 You can also run only a single category of tests. A category is a subdirectory
@@ -79,6 +81,7 @@ in the ``tests`` directory. There are a couple of special categories; for a
 list of these, see ``tests/testament/categories.nim``, at the bottom.
 
 ::
+
   ./koch tests c lib
 
 Comparing tests
@@ -92,6 +95,7 @@ reference test. You'll also need to the commit id, because that's what
 the tester needs to know in order to compare the two.
 
 ::
+
   git checkout devel
   DEVEL_COMMIT=$(git rev-parse HEAD)
   ./koch tests
@@ -99,6 +103,7 @@ the tester needs to know in order to compare the two.
 Then switch over to your changes and run the tester again.
 
 ::
+
   git checkout your-changes
   ./koch tests
 
@@ -106,6 +111,7 @@ Then you can ask the tester to create a ``testresults.html`` which will
 tell you if any new tests passed/failed.
 
 ::
+
   ./koch --print html $DEVEL_COMMIT
 
 
diff --git a/lib/pure/collections/tables.nim b/lib/pure/collections/tables.nim
index ec0d9623fb..be6b755ed2 100644
--- a/lib/pure/collections/tables.nim
+++ b/lib/pure/collections/tables.nim
@@ -226,6 +226,10 @@ proc `$`*[A, B](t: Table[A, B]): string =
   ## The `$` operator for hash tables.
   dollarImpl()
 
+proc hasKey*[A, B](t: TableRef[A, B], key: A): bool =
+  ## returns true iff `key` is in the table `t`.
+  result = t[].hasKey(key)
+
 template equalsImpl() =
   if s.counter == t.counter:
     # different insertion orders mean different 'data' seqs, so we have
@@ -293,10 +297,6 @@ proc hasKeyOrPut*[A, B](t: var TableRef[A, B], key: A, val: B): bool =
   ## returns true iff `key` is in the table, otherwise inserts `value`.
   t[].hasKeyOrPut(key, val)
 
-proc hasKey*[A, B](t: TableRef[A, B], key: A): bool =
-  ## returns true iff `key` is in the table `t`.
-  result = t[].hasKey(key)
-
 proc contains*[A, B](t: TableRef[A, B], key: A): bool =
   ## alias of `hasKey` for use with the `in` operator.
   return hasKey[A, B](t, key)
diff --git a/lib/pure/json.nim b/lib/pure/json.nim
index 49915b7e99..540a1a8eb7 100644
--- a/lib/pure/json.nim
+++ b/lib/pure/json.nim
@@ -608,29 +608,29 @@ proc newJArray*(): JsonNode =
 proc getStr*(n: JsonNode, default: string = ""): string =
   ## Retrieves the string value of a `JString JsonNode`.
   ##
-  ## Returns ``default`` if ``n`` is not a ``JString``.
-  if n.kind != JString: return default
+  ## Returns ``default`` if ``n`` is not a ``JString``, or if ``n`` is nil.
+  if n.isNil or n.kind != JString: return default
   else: return n.str
 
 proc getNum*(n: JsonNode, default: BiggestInt = 0): BiggestInt =
   ## Retrieves the int value of a `JInt JsonNode`.
   ##
-  ## Returns ``default`` if ``n`` is not a ``JInt``.
-  if n.kind != JInt: return default
+  ## Returns ``default`` if ``n`` is not a ``JInt``, or if ``n`` is nil.
+  if n.isNil or n.kind != JInt: return default
   else: return n.num
 
 proc getFNum*(n: JsonNode, default: float = 0.0): float =
   ## Retrieves the float value of a `JFloat JsonNode`.
   ##
-  ## Returns ``default`` if ``n`` is not a ``JFloat``.
-  if n.kind != JFloat: return default
+  ## Returns ``default`` if ``n`` is not a ``JFloat``, or if ``n`` is nil.
+  if n.isNil or n.kind != JFloat: return default
   else: return n.fnum
 
 proc getBVal*(n: JsonNode, default: bool = false): bool =
   ## Retrieves the bool value of a `JBool JsonNode`.
   ##
-  ## Returns ``default`` if ``n`` is not a ``JBool``.
-  if n.kind != JBool: return default
+  ## Returns ``default`` if ``n`` is not a ``JBool``, or if ``n`` is nil.
+  if n.isNil or n.kind != JBool: return default
   else: return n.bval
 
 proc getFields*(n: JsonNode,
@@ -638,15 +638,15 @@ proc getFields*(n: JsonNode,
         seq[tuple[key: string, val: JsonNode]] =
   ## Retrieves the key, value pairs of a `JObject JsonNode`.
   ##
-  ## Returns ``default`` if ``n`` is not a ``JObject``.
-  if n.kind != JObject: return default
+  ## Returns ``default`` if ``n`` is not a ``JObject``, or if ``n`` is nil.
+  if n.isNil or n.kind != JObject: return default
   else: return n.fields
 
 proc getElems*(n: JsonNode, default: seq[JsonNode] = @[]): seq[JsonNode] =
   ## Retrieves the int value of a `JArray JsonNode`.
   ##
-  ## Returns ``default`` if ``n`` is not a ``JArray``.
-  if n.kind != JArray: return default
+  ## Returns ``default`` if ``n`` is not a ``JArray``, or if ``n`` is nil.
+  if n.isNil or n.kind != JArray: return default
   else: return n.elems
 
 proc `%`*(s: string): JsonNode =
diff --git a/lib/pure/times.nim b/lib/pure/times.nim
index 78629af719..d9abbed1a1 100644
--- a/lib/pure/times.nim
+++ b/lib/pure/times.nim
@@ -1052,6 +1052,117 @@ proc parse*(value, layout: string): TimeInfo =
   info.weekday = getLocalTime(timeInfoToTime(info)).weekday
   return info
 
+# Leap year calculations are adapted from:
+# from http://www.codeproject.com/Articles/7358/Ultra-fast-Algorithms-for-Working-with-Leap-Years
+# The dayOfTheWeek procs are adapated from:
+# from http://stason.org/TULARC/society/calendars/2-5-What-day-of-the-week-was-2-August-1953.html
+
+# Note: for leap years, start date is assumed to be 1 AD.
+# counts the number of leap years up to January 1st of a given year.
+# Keep in mind that if specified year is a leap year, the leap day
+# has not happened before January 1st of that year.
+proc countLeapYears(yearSpan: int): int =
+  (((yearSpan - 1) / 4) - ((yearSpan - 1) / 100) + ((yearSpan - 1)/400)).int
+
+proc countDays(yearSpan: int): int =
+  (yearSpan - 1) * 365 + countLeapYears(yearSpan)
+
+proc countYears(daySpan: int): int =
+  # counts the number of years spanned by a given number of days.
+  ((daySpan - countLeapYears(daySpan div 365)) div 365)
+
+proc countYearsAndDays(daySpan: int): tuple[years: int, days: int] =
+  # counts the number of years spanned by a given number of days and the remainder as days.
+  let days = daySpan - countLeapYears(daySpan div 365)
+  result.years = days div 365
+  result.days = days mod 365
+
+const
+  secondsInMin = 60
+  secondsInHour = 60*60
+  secondsInDay = 60*60*24
+  epochStartYear = 1970
+
+proc getDayOfWeek*(day, month, year: int): WeekDay =
+  ## Returns the day of the week enum from day, month and year.
+  # Day & month start from one.
+  let
+    a = (14 - month) div 12
+    y = year - a
+    m = month + (12*a) - 2
+    d = (day + y + (y div 4) - (y div 100) + (y div 400) + (31*m) div 12) mod 7
+  # The value of d is 0 for a Sunday, 1 for a Monday, 2 for a Tuesday, etc. so we must correct
+  # for the WeekDay type.
+  if d == 0: return dSun
+  result = (d-1).WeekDay
+
+proc getDayOfWeekJulian*(day, month, year: int): WeekDay =
+  ## Returns the day of the week enum from day, month and year, according to the Julian calender.
+  # Day & month start from one.
+  let
+    a = (14 - month) div 12
+    y = year - a
+    m = month + (12*a) - 2
+    d = (5 + day + y + (y div 4) + (31*m) div 12) mod 7
+  result = d.WeekDay
+
+proc timeToTimeInfo*(t: Time): TimeInfo =
+  ## Converts a Time to TimeInfo.
+  let
+    daysSinceEpoch = t.int div secondsInDay
+    (yearsSinceEpoch, daysRemaining) = countYearsAndDays(daysSinceEpoch)
+    daySeconds = t.int mod secondsInDay
+
+    y = yearsSinceEpoch + epochStartYear
+
+  var
+    mon = mJan
+    days = daysRemaining
+    daysInMonth = getDaysInMonth(mon, y)
+
+  # calculate month and day remainder
+  while days > daysInMonth and mon <= mDec:
+    days -= daysInMonth
+    mon.inc
+    daysInMonth = getDaysInMonth(mon, y)
+
+  let
+    yd = daysRemaining
+    m = mon  # month is zero indexed enum
+    md = days
+    # NB: month is zero indexed but dayOfWeek expects 1 indexed.
+    wd = getDayOfWeek(days, mon.int + 1, y).Weekday
+    h = daySeconds div secondsInHour + 1
+    mi = (daySeconds mod secondsInHour) div secondsInMin
+    s = daySeconds mod secondsInMin
+  result = TimeInfo(year: y, yearday: yd, month: m, monthday: md, weekday: wd, hour: h, minute: mi, second: s)
+
+proc timetoTimeInterval*(t: Time): TimeInterval =
+  ## Converts a Time to a TimeInterval.
+  var
+    daysSinceEpoch = t.int div secondsInDay
+    (yearsSinceEpoch, daysRemaining) = countYearsAndDays(daysSinceEpoch)
+    daySeconds = t.int mod secondsInDay
+
+  result.years = yearsSinceEpoch + epochStartYear
+
+  var
+    mon = mJan
+    days = daysRemaining
+    daysInMonth = getDaysInMonth(mon, result.years)
+
+  # calculate month and day remainder
+  while days > daysInMonth and mon <= mDec:
+    days -= daysInMonth
+    mon.inc
+    daysInMonth = getDaysInMonth(mon, result.years)
+
+  result.months = mon.int + 1 # month is 1 indexed int
+  result.days = days
+  result.hours = daySeconds div secondsInHour + 1
+  result.minutes = (daySeconds mod secondsInHour) div secondsInMin
+  result.seconds = daySeconds mod secondsInMin
+  # Milliseconds not available from Time
 
 when isMainModule:
   # $ date --date='@2147483647'
@@ -1137,3 +1248,18 @@ when isMainModule:
   assert "15:04:00" in $s.parse(f)
   when not defined(testing):
     echo "Kitchen: " & $s.parse(f)
+    var ti = timeToTimeInfo(getTime())
+    echo "Todays date after decoding: ", ti
+    var tint = timeToTimeInterval(getTime())
+    echo "Todays date after decoding to interval: ", tint
+  # checking dayOfWeek matches known days
+  assert getDayOfWeek(21, 9, 1900) == dFri
+  assert getDayOfWeek(1, 1, 1970) == dThu
+  assert getDayOfWeek(21, 9, 1970) == dMon
+  assert getDayOfWeek(1, 1, 2000) == dSat
+  assert getDayOfWeek(1, 1, 2021) == dFri
+  # Julian tests
+  assert getDayOfWeekJulian(21, 9, 1900) == dFri
+  assert getDayOfWeekJulian(21, 9, 1970) == dMon
+  assert getDayOfWeekJulian(1, 1, 2000) == dSat
+  assert getDayOfWeekJulian(1, 1, 2021) == dFri
diff --git a/lib/pure/unittest.nim b/lib/pure/unittest.nim
index c459023a96..064937ad8b 100644
--- a/lib/pure/unittest.nim
+++ b/lib/pure/unittest.nim
@@ -285,7 +285,7 @@ macro check*(conditions: stmt): stmt {.immediate.} =
 
     result = getAst(rewrite(checked, checked.lineinfo, checked.toStrLit))
 
-template require*(conditions: stmt): stmt {.immediate, dirty.} =
+template require*(conditions: stmt): stmt {.immediate.} =
   ## Same as `check` except any failed test causes the program to quit
   ## immediately. Any teardown statements are not executed and the failed
   ## test output is not generated.
diff --git a/lib/system.nim b/lib/system.nim
index e5cae13363..7dae074f32 100644
--- a/lib/system.nim
+++ b/lib/system.nim
@@ -188,7 +188,7 @@ proc new*(T: typedesc): auto =
   ## reference to it as result value.
   ##
   ## When ``T`` is a ref type then the resulting type will be ``T``,
-  ## otherwise it will be ``ref T``. 
+  ## otherwise it will be ``ref T``.
   when (T is ref):
       var r: T
   else:
@@ -577,6 +577,9 @@ proc sizeof*[T](x: T): int {.magic: "SizeOf", noSideEffect.}
   ## that one never needs to know ``x``'s size. As a special semantic rule,
   ## ``x`` may also be a type identifier (``sizeof(int)`` is valid).
 
+when defined(nimtypedescfixed):
+  proc sizeof*(x: typedesc): int {.magic: "SizeOf", noSideEffect.}
+
 proc `<`*[T](x: Ordinal[T]): T {.magic: "UnaryLt", noSideEffect.}
   ## unary ``<`` that can be used for nice looking excluding ranges:
   ##
@@ -1500,7 +1503,7 @@ when not defined(nimrodVM):
       ## containing zero, so it is somewhat safer than ``createU``.
       ## The allocated memory belongs to its allocating thread!
       ## Use `createShared` to allocate from a shared heap.
-      cast[ptr T](alloc0(T.sizeof * size))
+      cast[ptr T](alloc0(sizeof(T) * size))
     proc realloc*(p: pointer, newSize: Natural): pointer {.noconv, rtl, tags: [],
                                                            benign.}
       ## grows or shrinks a given memory block. If p is **nil** then a new
diff --git a/tests/destructor/tdestructor3.nim b/tests/destructor/tdestructor3.nim
new file mode 100644
index 0000000000..0968f1fd75
--- /dev/null
+++ b/tests/destructor/tdestructor3.nim
@@ -0,0 +1,47 @@
+discard """
+  output: '''assign
+destroy
+destroy
+destroy Foo: 5
+5
+destroy Foo: 123
+123'''
+"""
+
+# bug #2821
+{.experimental.}
+
+type T = object
+
+proc `=`(lhs: var T, rhs: T) =
+    echo "assign"
+
+proc `=destroy`(v: var T) =
+    echo "destroy"
+
+block:
+    var v1 : T
+    var v2 : T = v1
+
+
+# bug #1632
+
+type
+  Foo = object of RootObj
+    x: int
+
+proc `=destroy`(a: var Foo) =
+  echo "destroy Foo: " & $a.x
+
+template toFooPtr(a: int{lit}): ptr Foo =
+  var temp = Foo(x:a)
+  temp.addr
+
+proc test(a: ptr Foo) =
+  echo a[].x
+
+proc main =
+  test(toFooPtr(5))
+  test(toFooPtr(123))
+
+main()
diff --git a/tests/exception/tdefer1.nim b/tests/exception/tdefer1.nim
index 61439530a1..cb3d09b01f 100644
--- a/tests/exception/tdefer1.nim
+++ b/tests/exception/tdefer1.nim
@@ -1,6 +1,11 @@
 discard """
   output: '''hi
-hi'''
+hi
+1
+hi
+2
+B
+A'''
 """
 
 # bug #1742
@@ -16,3 +21,23 @@ import strutils
 let x = try: parseInt("133a")
         except: -1
         finally: echo "hi"
+
+
+template atFuncEnd =
+  defer:
+    echo "A"
+  defer:
+    echo "B"
+
+template testB(): expr =
+    let a = 0
+    defer: echo "hi" # Delete this line to make it work
+    a
+
+proc main =
+  atFuncEnd()
+  echo 1
+  let i = testB()
+  echo 2
+
+main()
diff --git a/tests/generics/mclosed_sym.nim b/tests/generics/mclosed_sym.nim
new file mode 100644
index 0000000000..bcccd9a85d
--- /dev/null
+++ b/tests/generics/mclosed_sym.nim
@@ -0,0 +1,10 @@
+
+type R* = object
+
+type Data*[T] = object
+  d*: T
+
+proc same(r:R, d:int) = echo "TEST2"
+
+proc doIt*(d:Data, r:R) =
+  r.same(1)      # Expecting this to invoke the local `same()` method
diff --git a/tests/generics/tclosed_sym.nim b/tests/generics/tclosed_sym.nim
new file mode 100644
index 0000000000..ff620c2675
--- /dev/null
+++ b/tests/generics/tclosed_sym.nim
@@ -0,0 +1,11 @@
+discard """
+  output: "TEST2"
+"""
+
+# bug #2664
+
+import mclosed_sym
+
+proc same(r:R, d:int) = echo "TEST1"
+
+doIt(Data[int](d:123), R())
diff --git a/tests/destructor/tdictdestruct.nim b/tests/generics/tdictdestruct.nim
similarity index 100%
rename from tests/destructor/tdictdestruct.nim
rename to tests/generics/tdictdestruct.nim
diff --git a/tests/stdlib/tunittest.nim b/tests/stdlib/tunittest.nim
index fb9b022438..1389214ea5 100644
--- a/tests/stdlib/tunittest.nim
+++ b/tests/stdlib/tunittest.nim
@@ -21,6 +21,11 @@ test "unittest typedescs":
   check(none(int) != some(1))
 
 
+test "unittest multiple requires":
+  require(true)
+  require(true)
+
+
 import math
 from strutils import parseInt
 proc defectiveRobot() =
diff --git a/tests/template/twhen_gensym.nim b/tests/template/twhen_gensym.nim
new file mode 100644
index 0000000000..d84ee6f036
--- /dev/null
+++ b/tests/template/twhen_gensym.nim
@@ -0,0 +1,13 @@
+discard """
+  output: "hi"
+"""
+
+# bug #2670
+template testTemplate(b: bool): stmt =
+    when b:
+        var a = "hi"
+    else:
+        var a = 5
+    echo a
+
+testTemplate(true)