cgen: fix codegen for assign from unsafeexpr resulting fixed array (fix

#22301) (#22309)

vlib/v/gen/c/assign.v

@@ -399,7 +399,8 @@ fn (mut g Gen) assign_stmt(node_ ast.AssignStmt) {
 			&& (val in [ast.Ident, ast.IndexExpr, ast.CallExpr, ast.SelectorExpr, ast.DumpExpr, ast.InfixExpr]
 			|| (val is ast.CastExpr && val.expr !is ast.ArrayInit)
 			|| (val is ast.PrefixExpr && val.op == .arrow)
-			|| (val is ast.UnsafeExpr && val.expr is ast.Ident)) && !g.pref.translated
+			|| (val is ast.UnsafeExpr && val.expr in [ast.SelectorExpr, ast.Ident]))
+			&& !g.pref.translated
 		g.is_assign_lhs = true
 		g.assign_op = node.op
 

vlib/v/tests/assign/assign_array_fixed_from_union_test.v

@@ -0,0 +1,21 @@
+union Convertor {
+	su8_array_p  [20]u8
+	sint_array_p [5]int
+}
+
+fn test_main() {
+	a := [1, 2, 3, 4, 5]!
+	p := voidptr(unsafe { &Convertor(&a[0]) })
+	c := unsafe { &Convertor(p).su8_array_p }
+	dump(a)
+	dump(p)
+	dump(c)
+	assert a == [1, 2, 3, 4, 5]!
+	assert p != 0
+	$if little_endian {
+		assert c == [u8(1), 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 4, 0, 0, 0, 5, 0, 0, 0]!
+	}
+	$if big_endian {
+		assert c == [u8(0), 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 4, 0, 0, 0, 5]!
+	}
+}