tests: add a test for type inference involving sink

The existing `tsink_in_array.nim` test is merged into the new test.

Author: zerbina

tests/lang_types/array/tsink_in_array.nim

@@ -0,0 +1,36 @@
+discard """
+  description: '''
+    The `sink` parameter modifier is not part of the parameter expression's
+    effective type.
+  '''
+"""
+
+proc test(param: sink int8) =
+  # test let/var
+  let a = param
+  var b = param
+  # no need to typeof-test `a` and `b`, since even if `a` and `b` were
+  # inferred as `sink`-modified, `typeof` would drop the type
+
+  # test aggregate/composite type introduction
+  let tup = (param, param)
+  let named = (a: param, b: param)
+  let arr = [param]
+  let se = {param}
+
+  # test 'typeof'
+  var x: (typeof(param),)
+
+  doAssert $typeof(tup) == "(int8, int8)"
+  doAssert $typeof(named) == "tuple[a: int8, b: int8]"
+  doAssert $typeof(arr) == "array[0..0, int8]"
+  doAssert $typeof(se) == "set[int8]"
+  doAssert $typeof(x) == "(int8,)"
+
+test(1)
+
+# test parameter type inference from default value expression
+proc param_test(x: sink int, y = x) =
+  discard
+
+doAssert $typeof(param_test) == "proc (x: sink int, y: int){.noSideEffect, gcsafe, locks: 0.}"