Do not raise from Crystal::Type#lookup_type? if union type cannot be stored

spec/compiler/semantic/def_overload_spec.cr

@@ -1356,6 +1356,15 @@ describe "Semantic: def overload" do
       CRYSTAL
   end
 
+  it "says `no overload matches` instead of `use a more specific type` on union restriction that cannot be stored" do
+    assert_error <<-CRYSTAL, "expected argument #1 to 'foo' to be Array | String, not Int32"
+      def foo(x : Array | String)
+      end
+
+      foo(1)
+      CRYSTAL
+  end
+
   it "finds method after including module in generic module (#1201)" do
     assert_type(<<-CRYSTAL) { char }
       module Bar

src/compiler/crystal/semantic/type_lookup.cr

@@ -150,7 +150,10 @@ class Crystal::Type
         return if !@raise && !type
         type = type.not_nil!
 
-        check_type_can_be_stored(ident, type, "can't use #{type} in unions")
+        unless type.can_be_stored?
+          ident.raise "can't use #{type} in unions yet, use a more specific type" if @raise
+          return
+        end
 
         type.virtual_type
       end