v3: fix systemic parser/checker/transform/markused/gen issues; +75 passing tests (#27925)

Author: medvednikov

vlib/builtin/closure/closure.c.v

@@ -11,6 +11,8 @@ type ClosureGetDataFn = fn () voidptr
 
 type ClosureInitFn = fn ()
 
+type ClosureDataDropFn = fn (voidptr)
+
 struct ClosurePage {
 mut:
 	next            &ClosurePage = unsafe { nil }
@@ -21,6 +23,7 @@ struct ClosureLiveInfo {
 mut:
 	ctx        voidptr
 	owns_data  bool
+	drop_data  voidptr
 	generation u64
 }
 
@@ -354,11 +357,12 @@ fn closure_is_managed(exec_ptr voidptr) bool {
 	return false
 }
 
-fn closure_live_set(exec_ptr voidptr, data voidptr, owns_data bool) {
+fn closure_live_set(exec_ptr voidptr, data voidptr, owns_data bool, drop_data voidptr) {
 	g_closure.next_generation++
 	g_closure.live[exec_ptr] = ClosureLiveInfo{
 		ctx:        data
 		owns_data:  owns_data
+		drop_data:  drop_data
 		generation: g_closure.next_generation
 	}
 }
@@ -482,6 +486,14 @@ fn closure_release_no_lock(exec_ptr voidptr, generation u64) bool {
 	data := closure_slot_data(exec_ptr)
 	_ := closure_live_delete(exec_ptr)
 	if info.owns_data && !isnil(data) {
+		if !isnil(info.drop_data) {
+			drop_fn := ClosureDataDropFn(info.drop_data)
+			// A user-defined drop can allocate another closure. Run it outside the
+			// runtime mutex after removing this slot from the live map.
+			closure_mtx_unlock_platform()
+			drop_fn(data)
+			closure_mtx_lock_platform()
+		}
 		unsafe { free(data) }
 	}
 	unsafe {
@@ -796,6 +808,12 @@ fn closure_create(func voidptr, data voidptr) voidptr {
 // closure_create_with_data creates closure objects with explicit context ownership(INTERNAL COMPILER USE ONLY).
 @[direct_array_access]
 fn closure_create_with_data(func voidptr, data voidptr, owns_data bool) voidptr {
+	return closure_create_with_data_and_drop(func, data, owns_data, unsafe { nil })
+}
+
+// closure_create_with_data_and_drop creates an owned closure context with type-aware cleanup(INTERNAL COMPILER USE ONLY).
+@[direct_array_access]
+fn closure_create_with_data_and_drop(func voidptr, data voidptr, owns_data bool, drop_data voidptr) voidptr {
 	closure_ensure_initialized()
 	closure_mtx_lock_platform()
 
@@ -837,7 +855,7 @@ fn closure_create_with_data(func voidptr, data voidptr, owns_data bool) voidptr
 			p[1] = func // Target function to execute
 		}
 	}
-	closure_live_set(curr_closure, data, owns_data)
+	closure_live_set(curr_closure, data, owns_data, drop_data)
 	closure_lifetime_track_no_lock(curr_closure)
 	closure_mtx_unlock_platform()
 

vlib/v3/eval/eval.v

@@ -2482,6 +2482,9 @@ fn (mut e Eval) eval_expr(id flat.NodeId) !Value {
 				name: e.runtime_type_name(value)
 			}
 		}
+		.defer_result {
+			return error('`$res()` is not supported by the V3 eval backend')
+		}
 		.fn_literal {
 			return Value(e.eval_fn_literal(id, node)!)
 		}

vlib/v3/flat/flat.v

@@ -10,6 +10,8 @@ pub type NodeId = int
 pub type TextId = u32
 
 pub const empty_node = NodeId(-1)
+pub const method_value_borrow_receiver_marker = '__v3_method_value_borrow_receiver'
+pub const method_value_clone_receiver_marker_prefix = '__v3_method_value_clone_receiver:'
 
 const empty_node_value = Node{}
 
@@ -102,6 +104,9 @@ pub enum NodeKind as u8 {
 	// by parse_comptime_expr and fully expanded (into builder statements) by
 	// parse_block_body at parse time, so it never reaches later phases.
 	veb_template
+	// A `$res()` / `$res(index)` expression. This must remain distinct from
+	// `.ident` so user-spellable names cannot be reinterpreted as defer results.
+	defer_result
 }
 
 // Op lists op values used by flat.