test case for semistatic

tests/run/tsemistatic.nim

@@ -0,0 +1,24 @@
+discard """
+  msg: "static 10\ndynamic\nstatic 20\n"
+  output: "s\nd\nd\ns"
+"""
+
+proc foo(x: semistatic[int]) =
+  when isStatic(x):
+    static: echo "static ", x
+    echo "s"
+  else:
+    static: echo "dynamic"
+    echo "d"
+
+foo 10
+
+var
+  x = 10
+  y: int
+
+foo x
+foo y
+
+foo 20
+