better comptime match-statement support

compiler/checker/checker.odin

@@ -8637,39 +8637,23 @@ specialization_match_body :: proc(
 	if !ok || flow.kind != .Normal || subject == INVALID_CT_VALUE || int(subject) >= len(state.values) {
 		return nil, {}, false, false
 	}
-	value := state.values[subject]
-	if value.kind != .Struct || !types.is_tagged_union(value.type, &checker.module.types) {
+	selection, selected := ct_select_match_arm(&state, statement, subject, 0)
+	if !selected {
 		return nil, {}, false, false
 	}
-	for arm_id in statement.body {
-		arm := checker.ast_module.statements[arm_id]
-		if arm.kind != .Match_Arm || arm.pointer_capture {
-			continue
+	arm := checker.ast_module.statements[selection.arm]
+	if arm.pointer_capture {
+		return nil, {}, false, false
+	}
+	if len(arm.captures) > 0 {
+		if selection.payload == INVALID_CT_VALUE || types.is_void(selection.payload_type) {
+			return nil, {}, false, false
 		}
-		if len(arm.patterns) == 0 {
-			return arm.body, {}, false, true
-		}
-		for pattern_id in arm.patterns {
-			if pattern_id == ast.INVALID_EXPR || int(pattern_id) >= len(checker.ast_module.exprs) {
-				continue
-			}
-			pattern := checker.ast_module.exprs[pattern_id]
-			if pattern.kind != .Enum_Literal {
-				continue
-			}
-			if index, field, found := find_struct_field(checker, value.type, pattern.name); found && index == int(value.active) {
-				if len(arm.captures) > 0 && arm.captures[0] != checker.sink_symbol && !types.is_void(field.type) {
-					children := ct_child_slice(&state, value)
-					if len(children) == 0 {
-						return nil, {}, false, false
-					}
-					return arm.body, store_static_binding(checker, &state, children[0], arm.captures[0]), true, true
-				}
-				return arm.body, {}, false, true
-			}
+		if arm.captures[0] != checker.sink_symbol {
+			return arm.body, store_static_binding(checker, &state, selection.payload, arm.captures[0]), true, true
 		}
 	}
-	return nil, {}, false, false
+	return arm.body, {}, false, true
 }
 
 Inline_Binding_Error :: enum u8 {