fixes #2287

tests/parallel/tsimple_array_checks.nim

@@ -0,0 +1,41 @@
+# bug #2287
+
+import threadPool
+
+# If `nums` is an array instead of seq,
+# NONE of the iteration ways below work (including high / len-1)
+let nums = @[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+proc log(n:int) =
+  echo n
+
+proc main =
+  parallel:
+    for n in nums: # Error: cannot prove: i <= len(nums) + -1
+      spawn log(n)
+    #for i in 0 .. <nums.len: # Error: cannot prove: i <= len(nums) + -1
+    #for i in 0 .. nums.len-1: # WORKS!
+    #for i in 0 .. <nums.len: # WORKS!
+    #  spawn log(nums[i])
+
+# Array needs explicit size to work, probably related to issue #2287
+#const a: array[0..5, int] = [1,2,3,4,5,6]
+
+#const a = [1,2,3,4,5,6] # Doesn't work
+const a = @[1,2,3,4,5,6] # Doesn't work
+proc f(n: int) = echo "Hello ", n
+
+proc maino =
+  parallel:
+    # while loop doesn't work:
+    var i = 0
+    while i < a.high:
+      #for i in countup(0, a.high-1, 2):
+      spawn f(a[i])
+      spawn f(a[i+1])
+      i += 2
+
+maino() # Doesn't work outside a proc
+
+when isMainModule:
+  main()