fixes 10697 [backport]

(cherry picked from commit 257965e105)

compiler/jsgen.nim

@@ -476,6 +476,7 @@ proc binaryUintExpr(p: PProc, n: PNode, r: var TCompRes, op: string,
     r.res = "$1 = (($1 $2 $3) $4)" % [x.rdLoc, rope op, y.rdLoc, trimmer]
   else:
     r.res = "(($1 $2 $3) $4)" % [x.rdLoc, rope op, y.rdLoc, trimmer]
+  r.kind = resExpr
 
 proc ternaryExpr(p: PProc, n: PNode, r: var TCompRes, magic, frmt: string) =
   var x, y, z: TCompRes
@@ -1706,13 +1707,13 @@ proc genMagic(p: PProc, n: PNode, r: var TCompRes) =
   of mHigh:
     unaryExpr(p, n, r, "", "($1 != null ? ($1.length-1) : -1)")
   of mInc:
-    if n[1].typ.skipTypes(abstractRange).kind in tyUInt .. tyUInt64:
+    if n[1].typ.skipTypes(abstractRange).kind in {tyUInt..tyUInt64}:
       binaryUintExpr(p, n, r, "+", true)
     else:
       if optOverflowCheck notin p.options: binaryExpr(p, n, r, "", "$1 += $2")
       else: binaryExpr(p, n, r, "addInt", "$1 = addInt($1, $2)")
   of ast.mDec:
-    if n[1].typ.skipTypes(abstractRange).kind in tyUInt .. tyUInt64:
+    if n[1].typ.skipTypes(abstractRange).kind in {tyUInt..tyUInt64}:
       binaryUintExpr(p, n, r, "-", true)
     else:
       if optOverflowCheck notin p.options: binaryExpr(p, n, r, "", "$1 -= $2")

tests/js/tbasics.nim

@@ -0,0 +1,48 @@
+discard """
+  output: '''ABCDC
+1
+14
+ok
+1'''
+"""
+
+type
+  MyEnum = enum
+    A,B,C,D
+# trick the optimizer with an seq:
+var x = @[A,B,C,D]
+echo x[0],x[1],x[2],x[3],MyEnum(2)
+
+# bug #10651
+
+var xa: seq[int]
+var ya = @[1,2]
+xa &= ya
+echo xa[0]
+
+proc test =
+  var yup: seq[int]
+  try:
+    yup.add 14
+    echo yup.pop
+  finally:
+    discard
+
+test()
+
+when true:
+  var a: seq[int]
+
+  a.setLen(0)
+
+  echo "ok"
+
+# bug #10697
+proc test2 =
+  var val = uint16(0)
+  var i = 0
+  if i < 2:
+    val += uint16(1)
+  echo int(val)
+
+test2()