fixes #1783

tests/metatype/ttypedesc2.nim

@@ -0,0 +1,37 @@
+discard """
+  output: "(x: a)"
+"""
+
+type
+  Bar[T] = object
+    x: T
+
+proc infer(T: typeDesc): Bar[T] = Bar[T](x: 'a')
+
+let foo = infer(char)
+echo foo
+
+when true:
+  # bug #1783
+
+  type
+      uoffset_t* = uint32
+      FlatBufferBuilder* = object
+
+      uarray* {.unchecked.} [T]  = array [0..0, T]
+      Array* [T] = object
+          o*: uoffset_t
+          len*: int
+          data*: ptr uarray[T]
+
+  proc ca* (fbb: ptr FlatBufferBuilder, T: typedesc, len: int): Array[T] {.noinit.} =
+      result.len = len
+
+  var fbb: ptr FlatBufferBuilder
+  let boolarray = ca(fbb, bool, 2)
+  let boolarray2 = fbb.ca(bool, 2)
+
+# bug #1664
+type Point[T] = tuple[x, y: T]
+proc origin(T: typedesc): Point[T] = discard
+discard origin(int)