cgen: fix array to alias push operation (fix #22374) (#22375)

vlib/v/ast/types.v

@@ -441,6 +441,28 @@ fn (ts TypeSymbol) dbg_common(mut res []string) {
 	res << 'language: ${ts.language}'
 }
 
+pub fn (ts TypeSymbol) nr_dims() int {
+	match ts.info {
+		Alias {
+			parent_sym := global_table.sym(ts.info.parent_type)
+			if parent_sym.info is Array {
+				return parent_sym.info.nr_dims
+			}
+			return 0
+		}
+		Array {
+			elem_sym := global_table.sym(ts.info.elem_type)
+			if elem_sym.info is Alias {
+				return ts.info.nr_dims + elem_sym.nr_dims()
+			}
+			return ts.info.nr_dims
+		}
+		else {
+			return 0
+		}
+	}
+}
+
 // str returns a string representation of the type.
 pub fn (t Type) str() string {
 	return 'ast.Type(0x${t.hex()} = ${u32(t)})'

vlib/v/checker/containers.v

@@ -7,7 +7,7 @@ import v.token
 
 fn (mut c Checker) array_init(mut node ast.ArrayInit) ast.Type {
 	mut elem_type := ast.void_type
-	mut unwrap_elem_type := c.unwrap_generic(node.elem_type)
+	unwrap_elem_type := c.unwrap_generic(node.elem_type)
 	if c.pref.warn_about_allocs {
 		c.warn_alloc('array initialization', node.pos)
 	}
@@ -60,15 +60,6 @@ fn (mut c Checker) array_init(mut node ast.ArrayInit) ast.Type {
 					if elem_sym.name == 'byte' {
 						c.warn('byte is deprecated, use u8 instead', node.elem_type_pos)
 					}
-					parent_sym := c.table.sym(elem_sym.info.parent_type)
-					// check array to aliased array type
-					if parent_sym.info is ast.Array {
-						node.alias_type = c.table.find_or_register_array(unwrap_elem_type)
-						node.elem_type = c.table.find_or_register_array_with_dims(parent_sym.info.elem_type,
-							parent_sym.info.nr_dims)
-						unwrap_elem_type = node.elem_type
-						node.typ = c.table.find_or_register_array(node.elem_type)
-					}
 				}
 				else {}
 			}

vlib/v/gen/c/infix.v

@@ -842,7 +842,8 @@ fn (mut g Gen) infix_expr_left_shift_op(node ast.InfixExpr) {
 		noscan := g.check_noscan(array_info.elem_type)
 		if (right.unaliased_sym.kind == .array
 			|| (right.unaliased_sym.kind == .struct_ && right.unaliased_sym.name == 'array'))
-			&& array_info.elem_type != right.typ && !(right.sym.kind == .alias
+			&& left.sym.nr_dims() == right.sym.nr_dims() && array_info.elem_type != right.typ
+			&& !(right.sym.kind == .alias
 			&& g.table.sumtype_has_variant(array_info.elem_type, node.right_type, false)) {
 			// push an array => PUSH_MANY, but not if pushing an array to 2d array (`[][]int << []int`)
 			g.write('_PUSH_MANY${noscan}(')

vlib/v/tests/aliases/alias_array_push_test.v

@@ -0,0 +1,19 @@
+module main
+
+type NLRI = []u8
+
+fn make_loopback() []NLRI {
+	raw := [u8(32), 10, 0, 0, 1]
+	mut nlris := []NLRI{cap: 1}
+	nlris << NLRI(raw[0..5])
+	return nlris
+}
+
+fn test_main() {
+	r := make_loopback()
+	assert r[0][0] == 32
+	assert r[0][1] == 10
+	assert r[0][2] == 0
+	assert r[0][3] == 0
+	assert r[0][4] == 1
+}