From d141c05f4a0f87e116ea22301cbe0f8ffd151c97 Mon Sep 17 00:00:00 2001
From: metagn <metagngn@gmail.com>
Date: Sat, 5 Oct 2024 21:10:14 +0300
Subject: [PATCH] make new concepts match themselves

fixes #22839
---
 compiler/sigmatch.nim             |  7 +++++--
 tests/concepts/tintypesection.nim | 22 ++++++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)
 create mode 100644 tests/concepts/tintypesection.nim

diff --git a/compiler/sigmatch.nim b/compiler/sigmatch.nim
index 6ea2c7bb5781..bbebbb096cf6 100644
--- a/compiler/sigmatch.nim
+++ b/compiler/sigmatch.nim
@@ -1899,8 +1899,11 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
         else:
           result = isNone
   of tyConcept:
-    result = if concepts.conceptMatch(c.c, f, a, c.bindings, nil): isGeneric
-             else: isNone
+    if a.kind == tyConcept and sameType(f, a):
+      result = isGeneric
+    else:
+      result = if concepts.conceptMatch(c.c, f, a, c.bindings, nil): isGeneric
+               else: isNone
   of tyCompositeTypeClass:
     considerPreviousT:
       let roota = a.skipGenericAlias
diff --git a/tests/concepts/tintypesection.nim b/tests/concepts/tintypesection.nim
new file mode 100644
index 000000000000..92af7ebb54b4
--- /dev/null
+++ b/tests/concepts/tintypesection.nim
@@ -0,0 +1,22 @@
+# issues with concepts in type section types
+
+block: # issue #22839
+  type
+    Comparable = concept
+      proc `<`(a, b: Self): bool
+    
+    # Works with this.
+    # Comparable = concept a
+    #   `<`(a, a) is bool
+    
+    # Doesn't work with the new style concept.
+    Node[T: Comparable] = object
+      data: T
+      next: ref Node[T]
+
+  var x: Node[int]
+  type NotComparable = object
+  doAssert not (compiles do:
+    var y: Node[NotComparable])
+  proc `<`(a, b: NotComparable): bool = false
+  var z: Node[NotComparable]