fixes a regression where memset was used without including <string.h>

compiler/ccgexprs.nim

@@ -240,6 +240,7 @@ proc genGenericAsgn(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
   if needToCopy notin flags or 
       tfShallow in skipTypes(dest.t, abstractVarRange).flags:
     if dest.s == OnStack or not usesNativeGC():
+      useStringh(p.module)
       linefmt(p, cpsStmts,
            "memcpy((void*)$1, (NIM_CONST void*)$2, sizeof($3));$n",
            addrLoc(dest), addrLoc(src), rdLoc(dest))
@@ -316,6 +317,7 @@ proc genAssignment(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
     if needsComplexAssignment(dest.t):
       genGenericAsgn(p, dest, src, flags)
     else:
+      useStringh(p.module)
       linefmt(p, cpsStmts,
            "memcpy((void*)$1, (NIM_CONST void*)$2, sizeof($1));$n",
            rdLoc(dest), rdLoc(src))
@@ -327,11 +329,13 @@ proc genAssignment(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
            "#genericAssignOpenArray((void*)$1, (void*)$2, $1Len0, $3);$n",
            addrLoc(dest), addrLoc(src), genTypeInfo(p.module, dest.t))
     else:
+      useStringh(p.module)
       linefmt(p, cpsStmts,
            "memcpy((void*)$1, (NIM_CONST void*)$2, sizeof($1[0])*$1Len0);$n",
            rdLoc(dest), rdLoc(src))
   of tySet:
     if mapType(ty) == ctArray:
+      useStringh(p.module)
       linefmt(p, cpsStmts, "memcpy((void*)$1, (NIM_CONST void*)$2, $3);$n",
               rdLoc(dest), rdLoc(src), toRope(getSize(dest.t)))
     else:
@@ -1361,6 +1365,7 @@ proc genSetOp(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
       lineF(p, cpsStmts, lookupOpr[op],
            [rdLoc(i), toRope(size), rdLoc(d), rdLoc(a), rdLoc(b)])
     of mEqSet:
+      useStringh(p.module)
       binaryExprChar(p, e, d, "(memcmp($1, $2, " & $(size) & ")==0)")
     of mMulSet, mPlusSet, mMinusSet, mSymDiffSet:
       # we inline the simple for loop for better code generation:
@@ -1612,6 +1617,7 @@ proc genSetConstr(p: BProc, e: PNode, d: var TLoc) =
     if d.k == locNone: getTemp(p, e.typ, d)
     if getSize(e.typ) > 8:
       # big set:
+      useStringh(p.module)
       lineF(p, cpsStmts, "memset($1, 0, sizeof($1));$n", [rdLoc(d)])
       for i in countup(0, sonsLen(e) - 1):
         if e.sons[i].kind == nkRange:

compiler/cgen.nim

@@ -72,6 +72,11 @@ proc isSimpleConst(typ: PType): bool =
       {tyTuple, tyObject, tyArray, tyArrayConstr, tySet, tySequence} and not
       (t.kind == tyProc and t.callConv == ccClosure)
 
+proc useStringh(m: BModule) =
+  if not m.includesStringh:
+    m.includesStringh = true
+    discard lists.IncludeStr(m.headerFiles, "<string.h>")
+
 proc useHeader(m: BModule, sym: PSym) = 
   if lfHeader in sym.loc.Flags: 
     assert(sym.annex != nil)
@@ -358,6 +363,7 @@ proc resetLoc(p: BProc, loc: var TLoc) =
       # field, so disabling this should be safe:
       genObjectInit(p, cpsStmts, loc.t, loc, true)
     else:
+      useStringh(p.module)
       linefmt(p, cpsStmts, "memset((void*)$1, 0, sizeof($2));$n",
               addrLoc(loc), rdLoc(loc))
       # XXX: We can be extra clever here and call memset only 
@@ -368,6 +374,7 @@ proc constructLoc(p: BProc, loc: TLoc, section = cpsStmts) =
   if not isComplexValueType(skipTypes(loc.t, abstractRange)):
     linefmt(p, section, "$1 = 0;$n", rdLoc(loc))
   else:
+    useStringh(p.module)
     linefmt(p, section, "memset((void*)$1, 0, sizeof($2));$n",
             addrLoc(loc), rdLoc(loc))
     genObjectInit(p, section, loc.t, loc, true)
@@ -418,6 +425,7 @@ proc keepAlive(p: BProc, toKeepAlive: TLoc) =
     if not isComplexValueType(skipTypes(toKeepAlive.t, abstractVarRange)):
       linefmt(p, cpsStmts, "$1 = $2;$n", rdLoc(result), rdLoc(toKeepAlive))
     else:
+      useStringh(p.module)
       linefmt(p, cpsStmts,
            "memcpy((void*)$1, (NIM_CONST void*)$2, sizeof($3));$n",
            addrLoc(result), addrLoc(toKeepAlive), rdLoc(result))

compiler/cgendata.nim

@@ -91,6 +91,7 @@ type
     FrameDeclared*: bool      # hack for ROD support so that we don't declare
                               # a frame var twice in an init proc
     isHeaderFile*: bool       # C source file is the header file
+    includesStringh*: bool    # C source file already includes ``<string.h>``
     cfilename*: string        # filename of the module (including path,
                               # without extension)
     typeCache*: TIdTable      # cache the generated types

lib/system/gc.nim

@@ -629,7 +629,6 @@ proc doOperation(p: pointer, op: TWalkOp) =
   case op
   of waZctDecRef:
     #if not isAllocatedPtr(gch.region, c):
-    #  return
     #  c_fprintf(c_stdout, "[GC] decref bug: %p", c)
     gcAssert(isAllocatedPtr(gch.region, c), "decRef: waZctDecRef")
     gcAssert(c.refcount >=% rcIncrement, "doOperation 2")

tests/reject/twrongiter.nim

@@ -0,0 +1,13 @@
+discard """
+line: 14
+errormsg: "type mismatch"
+"""
+
+proc first(it: iterator(): int): seq[int] =
+  return @[]
+
+iterator primes(): int =
+  yield 1
+
+for i in first(primes):
+  break