Stop type aliases from inheriting sfUsed (#19861)

Fixes #18201

Co-authored-by: quantimnot <quantimnot@users.noreply.github.com>

1 files changed, 40 insertions, 13 deletions

diff --git a/tests/errmsgs/treportunused.nim b/tests/errmsgs/treportunused.nim
index f5ee79afa..46afe163d 100644
--- a/tests/errmsgs/treportunused.nim
+++ b/tests/errmsgs/treportunused.nim
@@ -2,19 +2,27 @@ discard """
   matrix: "--hint:all:off --hint:XDeclaredButNotUsed"
   nimoutFull: true
   nimout: '''
-treportunused.nim(23, 10) Hint: 's1' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(24, 10) Hint: 's2' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(25, 10) Hint: 's3' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(26, 6) Hint: 's4' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(27, 6) Hint: 's5' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(28, 7) Hint: 's6' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(29, 7) Hint: 's7' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(30, 5) Hint: 's8' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(31, 5) Hint: 's9' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(32, 6) Hint: 's10' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(33, 6) Hint: 's11' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(37, 3) Hint: 'v0.99' is declared but not used [XDeclaredButNotUsed]
-treportunused.nim(38, 3) Hint: 'v0.99.99' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(51, 5) Hint: 'A' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(52, 5) Hint: 'B' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(55, 5) Hint: 'D' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(56, 5) Hint: 'E' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(59, 5) Hint: 'G' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(60, 5) Hint: 'H' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(64, 5) Hint: 'K' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(65, 5) Hint: 'L' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(31, 10) Hint: 's1' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(32, 10) Hint: 's2' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(33, 10) Hint: 's3' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(34, 6) Hint: 's4' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(35, 6) Hint: 's5' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(36, 7) Hint: 's6' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(37, 7) Hint: 's7' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(38, 5) Hint: 's8' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(39, 5) Hint: 's9' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(40, 6) Hint: 's10' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(41, 6) Hint: 's11' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(45, 3) Hint: 'v0.99' is declared but not used [XDeclaredButNotUsed]
+treportunused.nim(46, 3) Hint: 'v0.99.99' is declared but not used [XDeclaredButNotUsed]
 '''
 action: compile
 """
@@ -36,3 +44,22 @@ type s11 = type(1.2)
 let
   `v0.99` = "0.99"
   `v0.99.99` = "0.99.99"
+
+block: # bug #18201
+  # Test that unused type aliases raise hint XDeclaredButNotUsed.
+  type
+    A = int
+    B = distinct int
+
+    C = object
+    D = C
+    E = distinct C
+
+    F = string
+    G = F
+    H = distinct F
+
+    J = enum
+      Foo
+    K = J
+    L = distinct J