fixes #14511 [backport:1.4] (#18732)

* fixes #14511 [backport:1.4]

Signed-off-by: Dankr4d <dude569@freenet.de>

* Replaced fix with code from alaviss, for better readability, with small
changes.

Signed-off-by: Dankr4d <dude569@freenet.de>

* - Specified output in test.

Signed-off-by: Dankr4d <dude569@freenet.de>

* Replaced case in nnkRecCase with a simpler version, which just adds the
last son.

Signed-off-by: Dankr4d <dude569@freenet.de>

* Update tests/macros/t14511.nim

* Update tests/macros/t14511.nim

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

tests/macros/t14511.nim

@@ -0,0 +1,54 @@
+discard """
+  output: "true\n(y: XInt, a: 5)\n(y: XString, b: \"abc\")"
+"""
+
+import macros
+
+block TEST_1:
+  # https://github.com/nim-lang/Nim/issues/14511
+
+  template myPragma() {.pragma.}
+
+  type
+    XType = enum
+      XInt,
+      XString,
+      XUnused
+    X = object
+      case y {.myPragma.}: XType
+        of XInt, XUnused:
+          a: int
+        else: # <-- Else case caused the "Error: index 1 not in 0 .. 0" error
+          b: string
+
+  var x: X = X(y: XInt, a: 5)
+  echo x.y.hasCustomPragma(myPragma)
+  echo x
+  echo X(y: XString, b: "abc")
+
+
+block TEST_2:
+  template myDevice(val: string) {.pragma.}
+  template myKey(val: string) {.pragma.}
+  template myMouse(val: string) {.pragma.}
+
+  type
+    Device {.pure.} = enum Keyboard, Mouse
+    Key = enum Key1, Key2
+    Mouse = enum Mouse1, Mouse2
+
+  type
+    Obj = object of RootObj
+      case device {.myDevice: "MyDevicePragmaStr".}: Device
+      of Device.Keyboard:
+        key {.myKey: "MyKeyPragmaStr".}: Key
+      else: # <-- Else case caused the "Error: index 1 not in 0 .. 0" error
+        mouse {.myMouse: "MyMousePragmaStr".}: Mouse
+
+  var obj: Obj
+  assert obj.device.hasCustomPragma(myDevice) == true
+  assert obj.key.hasCustomPragma(myKey) == true
+  assert obj.mouse.hasCustomPragma(myMouse) == true
+  assert obj.device.getCustomPragmaVal(myDevice) == "MyDevicePragmaStr"
+  assert obj.key.getCustomPragmaVal(myKey) == "MyKeyPragmaStr"
+  assert obj.mouse.getCustomPragmaVal(myMouse) == "MyMousePragmaStr"