fixes #21540; deref block at transf phase to make injectdestructors function properly (#21688)

* fixes #21540; deref block at transf phase to make injectdestructors function properly

* add a test case

* add one more test

* fixes the type of block

* transform block

1 files changed, 53 insertions, 2 deletions

diff --git a/tests/ccgbugs/tderefblock.nim b/tests/ccgbugs/tderefblock.nim
index fd21a19b8..d3ba07667 100644
--- a/tests/ccgbugs/tderefblock.nim
+++ b/tests/ccgbugs/tderefblock.nim
@@ -1,6 +1,5 @@
 discard """
-  cmd: "nim c -d:release -d:danger $file"
-  matrix: ";--gc:orc"
+  matrix: "--mm:refc -d:release -d:danger;--mm:orc -d:useMalloc -d:release -d:danger"
   output: "42"
 """
 
@@ -23,3 +22,55 @@ proc m() =
   echo $f.a
 
 m()
+
+block: # bug #21540
+  type
+    Option = object
+      val: string
+      has: bool
+
+  proc some(val: string): Option =
+    result.has = true
+    result.val = val
+
+  # Remove lent and it works
+  proc get(self: Option): lent string =
+    result = self.val
+
+  type
+    StringStream = ref object
+      data: string
+      pos: int
+
+  proc readAll(s: StringStream): string =
+    result = newString(s.data.len)
+    copyMem(addr(result[0]), addr(s.data[0]), s.data.len)
+
+  proc newStringStream(s: string = ""): StringStream =
+    new(result)
+    result.data = s
+
+  proc parseJson(s: string): string =
+    let stream = newStringStream(s)
+    result = stream.readAll()
+
+  proc main =
+    let initialFEN = block:
+      let initialFEN = some parseJson("startpos")
+      initialFEN.get
+
+    doAssert initialFEN == "startpos"
+
+  main()
+
+import std/[
+    json,
+    options
+]
+
+block: # bug #21540
+  let cheek = block:
+    let initialFEN = some("""{"initialFen": "startpos"}""".parseJson{"initialFen"}.getStr)
+    initialFEN.get
+
+  doAssert cheek == "startpos"