Attaching with address: localhost resolves to 127.0.0.1 when browser resolves to [::1]

[pl4nty]

• VS Code Version: 1.46.1
• Log file (set "trace": true in launch config):

  2020-6-21, 13:27:14.353 UTC
  [13:27:14.353 UTC] OS: win32 x64
  [13:27:14.353 UTC] Adapter node: v12.8.1 x64
  [13:27:14.353 UTC] vscode-chrome-debug-core: 6.7.50
  [13:27:14.353 UTC] debugger-for-edge: 1.0.15
  [13:27:14.353 UTC] From client: initialize({"clientID":"vscode","clientName":"Visual Studio Code","adapterID":"msedge","pathFormat":"path","linesStartAt1":true,"columnsStartAt1":true,"supportsVariableType":true,"supportsVariablePaging":true,"supportsRunInTerminalRequest":true,"locale":"en-gb","supportsProgressReporting":true})
  [13:27:14.353 UTC] To client: {"seq":0,"type":"response","request_seq":1,"command":"initialize","success":true,"body":{"exceptionBreakpointFilters":[{"label":"All Exceptions","filter":"all","default":false},{"label":"Uncaught Exceptions","filter":"uncaught","default":false}],"supportsConfigurationDoneRequest":true,"supportsSetVariable":true,"supportsConditionalBreakpoints":true,"supportsCompletionsRequest":true,"supportsHitConditionalBreakpoints":true,"supportsRestartFrame":true,"supportsExceptionInfoRequest":true,"supportsDelayedStackTraceLoading":true,"supportsValueFormattingOptions":true,"supportsEvaluateForHovers":true,"supportsLoadedSourcesRequest":true,"supportsRestartRequest":true,"supportsSetExpression":true,"supportsLogPoints":true}}
  [13:27:14.353 UTC] To client: {"seq":0,"type":"event","event":"output","body":{"category":"telemetry","output":"ClientRequest/initialize","data":{"Versions.DebugAdapterCore":"6.7.50","Versions.DebugAdapter":"1.0.15","successful":"true","timeTakenInMilliseconds":"2.8751","requestType":"request"}}}
  [13:27:14.353 UTC] From client: attach({"name":"Office Online (Edge)","type":"msedge","request":"attach","port":9222,"address":"localhost","trace":true,"url":"https://my_excel_online_url","webRoot":"C:\\Projects\\excel2latex","__sessionId":"684ffb9f-7610-401b-b2f0-3b2aa74ab181"})
  [13:27:14.353 UTC] To client: {"seq":0,"type":"event","event":"output","body":{"category":"telemetry","output":"debugStarted","data":{"Versions.DebugAdapterCore":"6.7.50","Versions.DebugAdapter":"1.0.15","request":"attach","args":["name","type","request","port","address","trace","url","webRoot","__sessionId","pathMapping","sourceMaps","sourceMapPathOverrides","skipFileRegExps","targetFilter","smartStep","showAsyncStacks"]}}}
  [13:27:14.353 UTC] Getting browser and debug protocol version via http://localhost:9222/json/version
  [13:27:14.353 UTC] Discovering targets via http://localhost:9222/json/list
  [13:27:16.353 UTC] HTTP GET failed: Error: connect ECONNREFUSED 127.0.0.1:9222
  [13:27:16.353 UTC] There was an error connecting to http://localhost:9222/json/version : connect ECONNREFUSED 127.0.0.1:9222
  [13:27:16.353 UTC] HTTP GET failed: Error: connect ECONNREFUSED 127.0.0.1:9222
  [13:27:16.353 UTC] Discovering targets via http://localhost:9222/json
  [13:27:18.356 UTC] HTTP GET failed: Error: connect ECONNREFUSED 127.0.0.1:9222
  [13:27:18.557 UTC] Getting browser and debug protocol version via http://localhost:9222/json/version
  [13:27:18.558 UTC] Discovering targets via http://localhost:9222/json/list
  [13:27:20.558 UTC] HTTP GET failed: Error: connect ECONNREFUSED 127.0.0.1:9222
  [13:27:20.558 UTC] There was an error connecting to http://localhost:9222/json/version : connect ECONNREFUSED 127.0.0.1:9222
  [13:27:20.559 UTC] HTTP GET failed: Error: connect ECONNREFUSED 127.0.0.1:9222
  [13:27:20.559 UTC] Discovering targets via http://localhost:9222/json
  [13:27:22.561 UTC] HTTP GET failed: Error: connect ECONNREFUSED 127.0.0.1:9222
  [13:27:22.761 UTC] Getting browser and debug protocol version via http://localhost:9222/json/version
  [13:27:22.761 UTC] Discovering targets via http://localhost:9222/json/list
  [13:27:24.766 UTC] HTTP GET failed: Error: connect ECONNREFUSED 127.0.0.1:9222
  [13:27:24.767 UTC] There was an error connecting to http://localhost:9222/json/version : connect ECONNREFUSED 127.0.0.1:9222
  [13:27:24.767 UTC] HTTP GET failed: Error: connect ECONNREFUSED 127.0.0.1:9222
  [13:27:24.767 UTC] Discovering targets via http://localhost:9222/json
  [13:27:26.770 UTC] HTTP GET failed: Error: connect ECONNREFUSED 127.0.0.1:9222
  [13:27:26.771 UTC] To client: {"seq":0,"type":"event","event":"output","body":{"category":"telemetry","output":"ClientRequest/attach","data":{"Versions.DebugAdapterCore":"6.7.50","Versions.DebugAdapter":"1.0.15","successful":"false","exceptionType":"firstChance","exceptionMessage":"Cannot connect to runtime process, timeout after {_timeout} ms - (reason: {_error}).","exceptionName":"Error","exceptionStack":"Error: Cannot connect to runtime process, timeout after {_timeout} ms - (reason: {_error}).\n    at Object.runtimeConnectionTimeout (errors.js:91:12)\n    at chromeConnection.js:110:49\n    at processTicksAndRejections (internal/process/task_queues.js:85:5)","exceptionId":"2010","timeTakenInMilliseconds":"12447.8142","requestType":"request"}}}
  [13:27:26.772 UTC] To client: {"seq":0,"type":"response","request_seq":2,"command":"attach","success":false,"message":"Cannot connect to runtime process, timeout after 10000 ms - (reason: Cannot connect to the target: connect ECONNREFUSED 127.0.0.1:9222).","body":{"error":{"id":2010,"format":"Cannot connect to runtime process, timeout after {_timeout} ms - (reason: {_error}).","variables":{"_error":"Cannot connect to the target: connect ECONNREFUSED 127.0.0.1:9222","_timeout":"10000"}}}}
  [13:27:26.778 UTC] From client: disconnect({"restart":false})
  [13:27:26.778 UTC] To client: {"seq":0,"type":"event","event":"output","body":{"category":"telemetry","output":"FullSessionStatistics/SourceMaps/Overrides","data":{"Versions.DebugAdapterCore":"6.7.50","Versions.DebugAdapter":"1.0.15","aspNetClientAppFallbackCount":0}}}
  [13:27:26.780 UTC] To client: {"seq":0,"type":"event","event":"output","body":{"category":"telemetry","output":"report-start-up-timings","data":{"Versions.DebugAdapterCore":"6.7.50","Versions.DebugAdapter":"1.0.15","RequestedContentWasDetected":"false","Steps":"[\"BeforeFirstStep\",\"ClientRequest/initialize\",\"ClientRequest/attach\",\"Attach\",\"Attach.RequestDebuggerTargetsInformation\",\"Attach.RequestDebuggerTargetsInformation\",\"Attach.RequestDebuggerTargetsInformation\"]","All":"12471.239599","BeforeFirstStep":"[9.7957]","WaitingAfter.ClientRequest/initialize":"[12.6087]","ClientRequest/initialize":"[5.465099]","ClientRequest/attach":"[2.689299]","Attach":"[20.9835]","Attach.RequestDebuggerTargetsInformation":"[4210.6893,4203.6924,4017.646]","WaitingAfter.ClientRequest/attach":"[12463.1181]","RequestedContentWasNotDetectedReason":"shutdown"}}}
  [13:27:26.780 UTC] Terminated: Got disconnect request
  [13:27:26.780 UTC] Waiting for any pending steps or log messages.
  [13:27:26.780 UTC] To client: {"seq":0,"type":"response","request_seq":3,"command":"disconnect","success":true}
  [13:27:26.780 UTC] To client: {"seq":0,"type":"event","event":"output","body":{"category":"telemetry","output":"ClientRequest/disconnect","data":{"Versions.DebugAdapterCore":"6.7.50","Versions.DebugAdapter":"1.0.15","successful":"true","timeTakenInMilliseconds":"2.0056","requestType":"request"}}}
  [13:27:26.780 UTC] Current step and log messages complete
  [13:27:26.780 UTC] To client: {"seq":0,"type":"event","event":"output","body":{"category":"telemetry","output":"debugStopped","data":{"Versions.DebugAdapterCore":"6.7.50","Versions.DebugAdapter":"1.0.15","reason":"Got disconnect request"}}}
  [13:27:26.781 UTC] To client: {"seq":0,"type":"event","event":"terminated"}

Steps to reproduce:

1. Configure these options:

     "type": "edge",
     "request": "attach",
     "port": 9222,
     "address": "localhost",
     "trace": true,
     "url": "https://my_excel_online_url",
     "webRoot": "${workspaceFolder}"

2. Open your site and attempt to attach the debugger
3. Observe timeout
4. When "address": "[::1]", issue is resolved

Observed when debugging a locally-hosted yo office Excel add-in sideloaded into Excel Online. localhost:9222/json/list and [::1]:9222/json/list resolve in-browser, but 127.0.0.1:9222/json/list does not.