fixes #22673; Cannot prove that result is initialized for a placehold… (#22915)

…er base method returning a lent

fixes #22673

(cherry picked from commit 2e070dfc76)

tests/method/t22673.nim

@@ -0,0 +1,21 @@
+discard """
+  matrix: "--warningAsError:UseBase"
+"""
+
+# bug #22673
+type RefEntry = ref object of RootObj
+
+type RefFile = ref object of RefEntry
+    filename*: string
+    data*: string
+
+type RefDir = ref object of RefEntry
+    dirname*: string
+    files*: seq[RefFile]
+
+method name*(e: RefEntry): lent string {.base.} =
+  raiseAssert "Don't call the base method"
+
+method name*(e: RefFile): lent string = e.filename
+
+method name*(e: RefDir): lent string = e.dirname