Go to Definition of function parameter jumps into first function having that parameter

System Details

• Operating system name and version: Win10 Anniversary Update
• VS Code version: 1.7.2
• PowerShell extension version: 0.7.2
• Output from $PSVersionTable:
  Name Value

PSVersion 5.1.14393.206
PSEdition Desktop
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
BuildVersion 10.0.14393.206
CLRVersion 4.0.30319.42000
WSManStackVersion 3.0
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1

Evaluate $PSVersionTable in PowerShell and paste the output here

Issue Description

I am experiencing a problem with "Go to Definition" feature. When file has multiple function having parameter with same name, "Go to Definition" jumps to first function declaration, regardless from which function parameter we examined. Testfile:

function f1($a) {
    $a + 1;
}

function f2 {
    param($a)
    $a + 2;
}

function f3 {
    param($a)
    $a + 3;
}

Action: Right click on $a inside f3 and select "Go to Definition"
Expected result: editor caret is planced before param $a in function f3 declaration
Actual result: editor caret is planced before param $a in function f1 declaration

The result does not depend on how params are defined (param keyword vs inline declaration)

Reproduce the report in the supplied PowerShell test file by invoking Go to Definition on $a inside f3, then trace the PowerShell extension's definition-provider entry point. Done means the command selects f3's parameter rather than the first matching declaration, for both inline and param-block forms.