From e4ce7f658741a7428597da4872435a1b0bae944c Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Sat, 3 Oct 2026 20:51:22 +0200
Subject: Rework generics for parameters to be plain types

---
 include/elna/boot/symbol.h     |  8 ++++----
 include/elna/boot/type_check.h | 15 +++++----------
 2 files changed, 9 insertions(+), 14 deletions(-)

(limited to 'include')

diff --git a/include/elna/boot/symbol.h b/include/elna/boot/symbol.h
index 31d5c45..705cb29 100644
--- a/include/elna/boot/symbol.h
+++ b/include/elna/boot/symbol.h
@@ -225,10 +225,10 @@ namespace elna::boot
     /**
      * Type parameter of a generic declaration.
      *
-     * It denotes an unknown pointer type chosen at instantiation, so it is
-     * usable wherever a pointer is, and erases to a pointer in the backend.
-     * Each declaration gets fresh parameters; two parameters spelled alike in
-     * different declarations never compare equal.
+     * It denotes an unknown opaque type chosen at instantiation, so it is
+     * usable only behind a pointer (^T), and ^T erases to a pointer in the
+     * backend. Each declaration gets fresh parameters; two parameters spelled
+     * alike in different declarations never compare equal.
      */
     struct parameter_type
     {
diff --git a/include/elna/boot/type_check.h b/include/elna/boot/type_check.h
index 5e4f792..5a2d7f1 100644
--- a/include/elna/boot/type_check.h
+++ b/include/elna/boot/type_check.h
@@ -177,10 +177,6 @@ namespace elna::boot
         {
             std::string parameter;
         };
-        struct argument_not_pointer
-        {
-            type actual;
-        };
         struct argument_not_scalar
         {
             type actual;
@@ -200,7 +196,7 @@ namespace elna::boot
         };
 
         using payload_type = std::variant<not_generic, unused_parameter,
-              argument_not_pointer, argument_not_scalar, constant_argument,
+              argument_not_scalar, constant_argument,
               uninferrable_parameter, shape_mismatch>;
 
         generic_error(const source_position position, const std::string& generic_name,
@@ -216,14 +212,13 @@ namespace elna::boot
     /**
      * What a generic declaration accepts as a type argument.
      *
-     * An erased generic takes a pointer, because that is what its single
-     * compiled body knows how to move.  A builtin has no body to erase, so it
-     * takes whatever it can load or store, and only a reading one tolerates a
-     * constant.
+     * An erased generic takes an opaque pointee, because it is only used
+     * behind a pointer. A builtin has no body to erase, so it takes whatever
+     * it can load or store, and only a reading one tolerates a constant.
      */
     enum class argument_rule
     {
-        pointer,
+        opaque,
         scalar,
         mutable_scalar
     };
-- 
cgit v1.2.3