Signature help returns wrong active parameter

[yyoncho]

E. g.

 Arrays.asList(1, 2);

[fbricon]

What would be the expected outcome?

[yyoncho]

IMO It should be the same as the outcome of Arrays.asList(1); . Apparently, vararg is considered as a single argument and does not match when there are more than one params.

[snjeza]

I can't reproduce the issue with vscode-java 0.45.0.

[yyoncho]

Yes, you are right, the problem actually is that activeParameter and activeSignature are not populated, compare the result with one and two parameters. I guess that VScode just assumes that the first parameter is active:

[Trace - 11:00:35 PM] Received response 'textDocument/signatureHelp - (222)' in 10ms.
Result: {
"signatures": [
               {
               "label": "asList(T... a) : List<T>",
               "documentation": " Returns a fixed-size list backed by the specified array. (Changes to the returned list \"write through\" to the array.) This method acts as bridge between array-based and collection-based APIs, in combination with Collection.toArray. The returned list is serializable and implements RandomAccess. \nThis method also provides a convenient way to create a fixed-size list initialized to contain several elements: \n List<String> stooges = Arrays.asList(\"Larry\", \"Moe\", \"Curly\"); \n * Parameters:\n   - <T> the class of the objects in the array\n   - a the array by which the list will be backed\n * Returns:\n   - a list view of the specified array",
               "parameters": [
                              {
                              "label": "T... a"
                              }
                              ]
               }
               ]
}

[Trace - 11:00:02 PM] Received response 'textDocument/signatureHelp - (205)' in 8ms.
Result: {
    "signatures": [
        {
            "label": "asList(T... a) : List<T>",
            "documentation": " Returns a fixed-size list backed by the specified array. (Changes to the returned list \"write through\" to the array.) This method acts as bridge between array-based and collection-based APIs, in combination with Collection.toArray. The returned list is serializable and implements RandomAccess. \nThis method also provides a convenient way to create a fixed-size list initialized to contain several elements: \n List<String> stooges = Arrays.asList(\"Larry\", \"Moe\", \"Curly\"); \n * Parameters:\n   - <T> the class of the objects in the array\n   - a the array by which the list will be backed\n * Returns:\n   - a list view of the specified array",
            "parameters": [
                {
                    "label": "T... a"
                }
            ]
        }
    ],
    "activeSignature": 0,
    "activeParameter": 0
}

This will reproduce the problem in vscode (it will select the first parameter as active, although it should select the second).

  public void demo (String s, String... s2) {
    demo("1", "2", "3");
  }

[snjeza]

The issue depends on #1051

[snjeza]

The following examples don't work properly:

new RuntimeException(new Exception(),|);

System.out.println(  |);