fixes #20107 (#20246) [backport]

tests/ccgbugs/tderefblock.nim

@@ -0,0 +1,24 @@
+discard """
+  cmd: "nim c -d:release -d:danger $file"
+  output: "42"
+"""
+
+# bug #20107
+
+type Foo = object
+  a, b, c, d: uint64
+
+proc c(i: uint64): Foo =
+  Foo(a: i, b: i, c: i, d: i)
+
+func x(f: Foo): lent Foo {.inline.} =
+  f
+
+proc m() =
+  let f = block:
+    let i = c(42)
+    x(i)
+
+  echo $f.a
+
+m()