add test for #13828

tests/template/mexport.nim

@@ -0,0 +1,19 @@
+import macros
+
+type
+  Storage[N: static[int]] = array[N, float32]
+  Quat* = object
+    data*: Storage[4]
+
+proc `[]`(q: Quat, index: int): float32 = q.data[index]
+proc `[]=`(q: var Quat, index: int, value: float32) = q.data[index] = value
+
+template genAccessor(t, a, i): untyped =
+  template a*(q: t): float32 {.inject.} = q[i]
+  template `a=`*(q: var t, value: float32) {.inject.} = q[i] = value
+
+genAccessor Quat, w, 0
+genAccessor Quat, x, 1
+genAccessor Quat, y, 2
+expandMacros:
+  genAccessor Quat, z, 3

tests/template/texport.nim

@@ -0,0 +1,9 @@
+# issue #13828
+
+import mexport
+
+var a = Quat()
+a.data = [1f,2,3,4]
+a.x = 42.0
+doAssert a.x == 42
+doAssert a.z == 4