CS8785 due to missing System.Text.Encodings.Web assembly in Dev16.11

[oold]

Actual behavior

Building the project fails to generate the sources when a NativeMethods.json file exists.

The following warning is emitted:

CSC : warning CS8785: Generator 'SourceGenerator' failed to generate source. It will not contribute to the output and compilation errors may occur as a result. Exception was of type 'FileNotFoundException' with message 'Could not load file or assembly 'System.Text.Encodings.Web, Version=4.0.5.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file specified.'

Expected behavior

The sources are successfully generated during the build.

Repro steps

1. NativeMethods.txt content:

CopyFileEx
CoTaskMemFree
ExtractIconEx
FileOpenDialog
FileSaveDialog
GetActiveWindow
GetModuleFileName
GetSystemWindowsDirectory
GetWindowLongPtr
HRESULT_FROM_WIN32
IFileDialog
IShellItem2
ITaskbarList3
SendMessage
SetWindowLongPtr
SHCreateItemFromParsingName
ShellExecuteEx
SHGetFileInfo
SHGetKnownFolderItem
SHGetStockIconInfo
SHOpenFolderAndSelectItems
SHParseDisplayName
StrCmpLogical
TaskbarList
TaskDialogIndirect

E_*
FOLDERID_*
ICON_*
MAX_PATH
MESSAGEBOX_RESULT
PBST_*
S_*
SEE_MASK_*
SHOW_WINDOW_CMD
TASKDIALOG_ELEMENTS
TASKDIALOG_MESSAGES
TD_*
WIN32_ERROR
WINDOW_EX_STYLE
WM_*

2. NativeMethods.json content (if present):

{
  "$schema": "https://aka.ms/CsWin32.schema.json",
  "comInterop": {
    "preserveSigMethods": [
      "IFileDialogEvents"
    ]
  }
}

3. Any of your own code that should be shared?

Context

• CsWin32 version: 0.3.49-beta
• Win32Metadata version (if explicitly set by project): 59.0.13-preview
• Target Framework: net5.0-windows
• LangVersion (if explicitly set by project): -

[AArnott]

Note: Your target framework (net5.0-windows) is no longer supported.

System.Text.Encodings.Web being missing suggests you're running on a compiler that's older than one we test with. What .NET SDK or VS version are you building with?

[oold]

Running on the latest VS 16 version.

[AArnott]

It works for me:

Can you send more repro details?

[AArnott]

Actually, I could repro it after filling in the Nativemethods text files like you described.