fix #10339 by returning type attached to nkEmpty (#10370)

* fix #10339 by checking for nkObjConstr

* revert check for nkObjConstr, return type from nkEmpty node

The correct type needed in `semObjConstr` to fix #10339 is indeed
available, but attached to an `nkEmpty` node. These were previously
discarded in `semTypeNode`, which is used to extract the type for the
object.

* simplify return of PType from  `nkEmpty`

* also fixes #9866, add test case

compiler/semtypes.nim

@@ -1474,7 +1474,7 @@ proc semTypeNode(c: PContext, n: PNode, prev: PType): PType =
 
   if c.config.cmd == cmdIdeTools: suggestExpr(c, n)
   case n.kind
-  of nkEmpty: discard
+  of nkEmpty: result = n.typ
   of nkTypeOfExpr:
     # for ``type(countup(1,3))``, see ``tests/ttoseq``.
     checkSonsLen(n, 1, c.config)

tests/macros/tquotedo.nim

@@ -4,6 +4,7 @@ output: '''
 Hallo Welt
 Hallo Welt
 1
+()
 '''
 """
 
@@ -34,3 +35,17 @@ macro t(): untyped =
 t()
 
 echo tp()
+
+
+# https://github.com/nim-lang/Nim/issues/9866
+type
+  # Foo = int # works
+  Foo = object # fails
+
+macro dispatchGen(): untyped =
+  var shOpt: Foo
+  result = quote do:
+    let baz = `shOpt`
+    echo `shOpt`
+
+dispatchGen()

tests/statictypes/tstatictypes.nim

@@ -137,3 +137,20 @@ block:
   type
     Coord[N: static[int]] = tuple[col, row: range[0'i8 .. (N.int8-1)]]
     Point[N: static[int]] = range[0'i16 .. N.int16 * N.int16 - 1]
+
+# https://github.com/nim-lang/Nim/issues/10339
+block:
+  type
+    MicroKernel = object
+      a: float
+      b: int
+
+  macro extractA(ukernel: static MicroKernel): untyped =
+    result = newLit ukernel.a
+
+  proc tFunc[ukernel: static MicroKernel]() =
+    const x = ukernel.extractA
+    doAssert x == 5.5
+
+  const uk = MicroKernel(a: 5.5, b: 1)
+  tFunc[uk]()