fixes regression: constant fac4 didn't work

compiler/parser.nim

@@ -35,6 +35,7 @@ type
     lex*: TLexer              # the lexer that is used for parsing
     tok*: TToken              # the current token
     inPragma: int
+    inSemiStmtList: int
 
 proc parseAll*(p: var TParser): PNode
 proc openParser*(p: var TParser, filename: string, inputstream: PLLStream)
@@ -455,11 +456,13 @@ proc complexOrSimpleStmt(p: var TParser): PNode
 proc simpleExpr(p: var TParser, mode = pmNormal): PNode
 
 proc semiStmtList(p: var TParser, result: PNode) =
+  inc p.inSemiStmtList
   result.add(complexOrSimpleStmt(p))
   while p.tok.tokType == tkSemiColon:
     getTok(p)
     optInd(p, result)
     result.add(complexOrSimpleStmt(p))
+  dec p.inSemiStmtList
   result.kind = nkStmtListExpr
 
 proc parsePar(p: var TParser): PNode =
@@ -1880,6 +1883,10 @@ proc parseStmt(p: var TParser): PNode =
        tkMacro, tkType, tkConst, tkWhen, tkVar:
       parMessage(p, errComplexStmtRequiresInd)
       result = ast.emptyNode
+    else:
+      if p.inSemiStmtList > 0:
+        result = simpleStmt(p)
+        if result.kind == nkEmpty: parMessage(p, errExprExpected, p.tok)
       else:
         result = newNodeP(nkStmtList, p)
         while true:

compiler/vm.nim

@@ -14,7 +14,7 @@ import ast except getstr
 
 import
   strutils, astalgo, msgs, vmdef, vmgen, nimsets, types, passes, unsigned,
-  parser, vmdeps, idents, trees, renderer, options
+  parser, vmdeps, idents, trees, renderer, options, transf
 
 from semfold import leValueConv, ordinalValToString
 from evaltempl import evalTemplate
@@ -1078,6 +1078,7 @@ proc execute(c: PCtx, start: int): PNode =
   result = rawExecute(c, start, tos)
 
 proc evalStmt*(c: PCtx, n: PNode) =
+  let n = transformExpr(c.module, n)
   let start = genStmt(c, n)
   # execute new instructions; this redundant opcEof check saves us lots
   # of allocations in 'execute':
@@ -1085,6 +1086,7 @@ proc evalStmt*(c: PCtx, n: PNode) =
     discard execute(c, start)
 
 proc evalExpr*(c: PCtx, n: PNode): PNode =
+  let n = transformExpr(c.module, n)
   let start = genExpr(c, n)
   assert c.code[start].opcode != opcEof
   result = execute(c, start)
@@ -1127,6 +1129,7 @@ proc myProcess(c: PPassContext, n: PNode): PNode =
 const evalPass* = makePass(myOpen, nil, myProcess, myProcess)
 
 proc evalConstExprAux(module, prc: PSym, n: PNode, mode: TEvalMode): PNode =
+  let n = transformExpr(module, n)
   setupGlobalCtx(module)
   var c = globalCtx
   c.mode = mode

compiler/vmgen.nim

@@ -1033,7 +1033,7 @@ proc genRdVar(c: PCtx; n: PNode; dest: var TDest) =
   if s.isGlobal:
     if sfCompileTime in s.flags or c.mode == emRepl:
       discard
-    else:
+    elif s.position == 0:
       cannotEval(n)
     if s.position == 0:
       if sfImportc in s.flags: c.importcSym(n.info, s)

tests/exprs/tstmtexprs.nim

@@ -1,5 +1,6 @@
 discard """
-  output: '''(bar: bar)
+  output: '''24
+(bar: bar)
 1244
 6
 abcdefghijklmnopqrstuvwxyz
@@ -8,6 +9,10 @@ abcdefghijklmnopqrstuvwxyz
 
 import strutils
 
+const fac4 = (var x = 1; for i in 1..4: x *= i; x)
+
+echo fac4
+
 when true:
   proc test(foo: proc (x, y: int): bool) =
     echo foo(5, 5)