cgen: fix multiple fixed array variable init (fix #20895) (#20902)

vlib/v/gen/c/array.v

@@ -56,7 +56,8 @@ fn (mut g Gen) array_init(node ast.ArrayInit, var_name string) {
 				} else if elem_type.unaliased_sym.kind == .array_fixed
 					&& expr in [ast.Ident, ast.SelectorExpr] {
 					info := elem_type.unaliased_sym.info as ast.ArrayFixed
-					g.fixed_array_var_init(expr, info.size)
+					g.fixed_array_var_init(g.expr_string(expr), expr.is_auto_deref_var(),
+						info.elem_type, info.size)
 				} else {
 					g.expr_with_cast(expr, node.expr_types[i], node.elem_type)
 				}
@@ -162,7 +163,8 @@ fn (mut g Gen) fixed_array_init(node ast.ArrayInit, array_type Type, var_name st
 		for i, expr in node.exprs {
 			if elem_sym.kind == .array_fixed && expr in [ast.Ident, ast.SelectorExpr] {
 				info := elem_sym.info as ast.ArrayFixed
-				g.fixed_array_var_init(expr, info.size)
+				g.fixed_array_var_init(g.expr_string(expr), expr.is_auto_deref_var(),
+					info.elem_type, info.size)
 			} else {
 				if expr.is_auto_deref_var() {
 					g.write('*')
@@ -1339,17 +1341,23 @@ fn (mut g Gen) write_prepared_var(var_name string, inp_info ast.Array, inp_elem_
 	}
 }
 
-fn (mut g Gen) fixed_array_var_init(expr ast.Expr, size int) {
+fn (mut g Gen) fixed_array_var_init(expr_str string, is_auto_deref bool, elem_type ast.Type, size int) {
 	g.write('{')
 	for i in 0 .. size {
-		if expr.is_auto_deref_var() {
-			g.write('(*')
-		}
-		g.expr(expr)
-		if expr.is_auto_deref_var() {
-			g.write(')')
+		elem_sym := g.table.sym(elem_type)
+		if elem_sym.info is ast.ArrayFixed {
+			g.fixed_array_var_init('${expr_str}[${i}]', is_auto_deref, elem_sym.info.elem_type,
+				elem_sym.info.size)
+		} else {
+			if is_auto_deref {
+				g.write('(*')
+			}
+			g.write(expr_str)
+			if is_auto_deref {
+				g.write(')')
+			}
+			g.write('[${i}]')
 		}
-		g.write('[${i}]')
 		if i != size - 1 {
 			g.write(', ')
 		}

vlib/v/gen/c/cgen.v

@@ -5397,7 +5397,9 @@ fn (mut g Gen) return_stmt(node ast.Return) {
 			}
 			for i, expr in node.exprs {
 				if return_sym.kind == .array_fixed && expr !is ast.ArrayInit {
-					g.fixed_array_var_init(expr, (return_sym.info as ast.ArrayFixed).size)
+					info := return_sym.info as ast.ArrayFixed
+					g.fixed_array_var_init(g.expr_string(expr), expr.is_auto_deref_var(),
+						info.elem_type, info.size)
 				} else {
 					g.expr_with_cast(expr, node.types[i], fn_ret_type.clear_option_and_result())
 				}
@@ -5432,7 +5434,9 @@ fn (mut g Gen) return_stmt(node ast.Return) {
 				if fn_ret_type.has_flag(.option) {
 					g.expr_with_opt(expr, node.types[i], fn_ret_type.clear_flag(.result))
 				} else if return_sym.kind == .array_fixed && expr !is ast.ArrayInit {
-					g.fixed_array_var_init(expr, (return_sym.info as ast.ArrayFixed).size)
+					info := return_sym.info as ast.ArrayFixed
+					g.fixed_array_var_init(g.expr_string(expr), expr.is_auto_deref_var(),
+						info.elem_type, info.size)
 				} else {
 					g.expr_with_cast(expr, node.types[i], fn_ret_type.clear_flag(.result))
 				}

vlib/v/gen/c/struct.v

@@ -603,7 +603,8 @@ fn (mut g Gen) struct_init_field(sfield ast.StructInitField, language ast.Langua
 		field_unwrap_sym := g.table.sym(g.unwrap_generic(sfield.typ))
 		if field_unwrap_sym.kind == .array_fixed && sfield.expr in [ast.Ident, ast.SelectorExpr] {
 			info := field_unwrap_sym.info as ast.ArrayFixed
-			g.fixed_array_var_init(sfield.expr, info.size)
+			g.fixed_array_var_init(g.expr_string(sfield.expr), sfield.expr.is_auto_deref_var(),
+				info.elem_type, info.size)
 		} else {
 			if sfield.typ != ast.voidptr_type && sfield.typ != ast.nil_type
 				&& (sfield.expected_type.is_ptr() && !sfield.expected_type.has_flag(.shared_f))

vlib/v/tests/multiple_fixed_array_var_init_test.v

@@ -0,0 +1,41 @@
+struct Cell {
+	value  int
+	fvalue f32
+mut:
+	mut_value  int = 10
+	mut_fvalue f32
+}
+
+struct Grid {
+	cells [2][2][2]Cell
+}
+
+fn test_multiple_fixed_array_var_init() {
+	mut tile_field := [2][2][2]Cell{}
+
+	b := Grid{
+		cells: tile_field
+	}
+
+	println('The original:')
+	println(tile_field)
+	println('==========')
+	println('The struct:')
+	println(b.cells)
+	assert b.cells[0][0][0].value == 0
+	assert b.cells[0][0][0].mut_value == 10
+	assert b.cells[0][0][1].value == 0
+	assert b.cells[0][0][1].mut_value == 10
+	assert b.cells[0][1][0].value == 0
+	assert b.cells[0][1][0].mut_value == 10
+	assert b.cells[0][1][1].value == 0
+	assert b.cells[0][1][1].mut_value == 10
+	assert b.cells[1][0][0].value == 0
+	assert b.cells[1][0][0].mut_value == 10
+	assert b.cells[1][0][1].value == 0
+	assert b.cells[1][0][1].mut_value == 10
+	assert b.cells[1][1][0].value == 0
+	assert b.cells[1][1][0].mut_value == 10
+	assert b.cells[1][1][1].value == 0
+	assert b.cells[1][1][1].mut_value == 10
+}