cgen: fix map value init with array fixed const (fix #25887) (#25902)

Author: felipensp

vlib/v/gen/c/cgen.v

@@ -5122,6 +5122,9 @@ fn (mut g Gen) map_init(node ast.MapInit) {
 				g.expr_with_cast(expr, node.val_types[i], unwrap_val_typ)
 			} else if node.val_types[i].has_flag(.option) || node.val_types[i] == ast.none_type {
 				g.expr_with_opt(expr, node.val_types[i], unwrap_val_typ)
+			} else if expr !is ast.ArrayInit && value_sym.info is ast.ArrayFixed {
+				tmpvar := g.expr_with_var(expr, node.val_types[i], false)
+				g.fixed_array_var_init(tmpvar, false, value_sym.info.elem_type, value_sym.info.size)
 			} else {
 				g.expr(expr)
 			}

vlib/v/tests/builtin_arrays/array_fixed_map_values_test.v

@@ -0,0 +1,11 @@
+const invalid = [0, 0, 0]!
+
+fn test_main() {
+	m := {
+		'1,1,1': [1, 1, 1]!
+		'?':     invalid
+		'2,2,2': [2, 2, 2]!
+	}
+	assert m['1,1,1'] == [1, 1, 1]!
+	assert m['?'] == invalid
+}