5 files changed, 74 insertions, 69 deletions
diff --git a/tests/array/troof1.nim b/tests/array/troof1.nim
index 96669a121..b486c3448 100644
--- a/tests/array/troof1.nim
+++ b/tests/array/troof1.nim
@@ -1,7 +1,11 @@
 discard """
   output: '''@[2, 3, 4]321
 9.0 4.0
-(a: 1.0, b: 2.0, c: 8.0)2.0'''
+3
+@[(Field0: 1, Field1: 2), (Field0: 3, Field1: 5)]
+2
+@["a", "new one", "c"]
+@[1, 2, 3]'''
 """
 
 proc foo[T](x, y: T): T = x
@@ -11,26 +15,29 @@ var b: array[3, array[2, float]] = [[1.0,2], [3.0,4], [8.0,9]]
 echo a[1.. ^1], a[^2], a[^3], a[^4]
 echo b[^1][^1], " ", (b[^2]).foo(b[^1])[^1]
 
-type
-  MyArray = object
-    a, b, c: float
+b[^1] = [8.8, 8.9]
 
-var
-  ma = MyArray(a: 1.0, b: 2.0, c: 3.0)
+var c: seq[(int, int)] = @[(1,2), (3,4)]
 
-proc len(x: MyArray): int = 3
+proc takeA(x: ptr int) = echo x[]
 
-proc `[]=`(x: var MyArray; idx: range[0..2]; val: float) =
-  case idx
-  of 0: x.a = val
-  of 1: x.b = val
-  of 2: x.c = val
+takeA(addr c[^1][0])
+c[^1][1] = 5
+echo c
 
-proc `[]`(x: var MyArray; idx: range[0..2]): float =
-  case idx
-  of 0: result = x.a
-  of 1: result = x.b
-  of 2: result = x.c
+proc useOpenarray(x: openArray[int]) =
+  echo x[^2]
 
-ma[^1] = 8.0
-echo ma, ma[^2]
+proc mutOpenarray(x: var openArray[string]) =
+  x[^2] = "new one"
+
+useOpenarray([1, 2, 3])
+
+var z = @["a", "b", "c"]
+mutOpenarray(z)
+echo z
+
+# bug #6675
+var y: array[1..5, int] = [1,2,3,4,5]
+y[3..5] = [1, 2, 3]
+echo y[3..5]
diff --git a/tests/array/troof2.nim b/tests/array/troof2.nim
deleted file mode 100644
index e4b4f4b3c..000000000
--- a/tests/array/troof2.nim
+++ /dev/null
@@ -1,10 +0,0 @@
-discard """
-  errormsg: "invalid context for '^' as 'foo()' has side effects"
-  line: "9"
-"""
-# XXX This needs to be fixed properly!
-proc foo(): seq[int] {.sideEffect.} =
-  echo "ha"
-
-let f = foo()[^1]
-
diff --git a/tests/array/troof3.nim b/tests/array/troof3.nim
index 4b6e22223..efe0eafb8 100644
--- a/tests/array/troof3.nim
+++ b/tests/array/troof3.nim
@@ -1,8 +1,7 @@
 discard """
-  errormsg: "invalid context for '^' as len!=high+1 for 'a'"
-  line: "8"
+  output: '''c'''
 """
 
-var a: array[1..3, string]
+var a: array['a'..'c', string] = ["a", "b", "c"]
 
 echo a[^1]
diff --git a/tests/array/troof4.nim b/tests/array/troof4.nim
deleted file mode 100644
index 7a262d9de..000000000
--- a/tests/array/troof4.nim
+++ /dev/null
@@ -1,37 +0,0 @@
-discard """
-  errormsg: "no surrounding array access context for '^'"
-  line: "37"
-"""
-
-proc foo[T](x, y: T): T = x
-
-var a = @[1, 2, 3, 4]
-var b: array[3, array[2, float]] = [[1.0,2], [3.0,4], [8.0,9]]
-echo a[1.. ^1], a[^2], a[^3], a[^4]
-echo b[^1][^1], " ", (b[^2]).foo(b[^1])[^1]
-
-type
-  MyArray = object
-    a, b, c: float
-
-var
-  ma = MyArray(a: 1.0, b: 2.0, c: 3.0)
-
-proc len(x: MyArray): int = 3
-
-proc `[]=`(x: var MyArray; idx: range[0..2]; val: float) =
-  case idx
-  of 0: x.a = val
-  of 1: x.b = val
-  of 2: x.c = val
-
-proc `[]`(x: var MyArray; idx: range[0..2]): float =
-  case idx
-  of 0: result = x.a
-  of 1: result = x.b
-  of 2: result = x.c
-
-ma[^1] = 8.0
-echo ma, ma[^2]
-
-echo(^1)
diff --git a/tests/array/troofregression.nim b/tests/array/troofregression.nim
new file mode 100644
index 000000000..0b96123a4
--- /dev/null
+++ b/tests/array/troofregression.nim
@@ -0,0 +1,46 @@
+###############################
+#### part from Arraymancer
+
+type
+  MetadataArray* = object
+    data*: array[8, int]
+    len*: int
+
+# Commenting the converter removes the error "lib/system.nim(3536, 3) Error: for a 'var' type a variable needs to be passed"
+converter toMetadataArray*(se: varargs[int]): MetadataArray {.inline.} =
+  result.len = se.len
+  for i in 0..<se.len:
+    result.data[i] = se[i]
+
+
+when NimVersion >= "0.17.3":
+  type Index = int or BackwardsIndex
+  template `^^`(s, i: untyped): untyped =
+    when i is BackwardsIndex:
+      s.len - int(i)
+    else: i
+else:
+  type Index = int
+  template `^^`(s, i: untyped): untyped =
+    i
+
+## With Nim devel from the start of the week (~Oct30) I managed to trigger "lib/system.nim(3536, 4) Error: expression has no address"
+## but I can't anymore after updating Nim (Nov5)
+## Now commenting this plain compiles and removes the error "lib/system.nim(3536, 3) Error: for a 'var' type a variable needs to be passed"
+proc `[]`*(a: var MetadataArray, idx: Index): var int {.inline.} =
+  a.data[a ^^ idx]
+
+
+##############################
+### Completely unrelated lib that triggers the issue
+
+type
+  MySeq[T] = ref object
+    data: seq[T]
+
+proc test[T](sx: MySeq[T]) =
+  # Removing the backward index removes the error "lib/system.nim(3536, 3) Error: for a 'var' type a variable needs to be passed"
+  echo sx.data[^1] # error here
+
+let s = MySeq[int](data: @[1, 2, 3])
+s.test()