Roslyn: [x64](3.0.100-preview-010184) Switch expression bug

[RUSshy]

Hi

Looks like the new pattern matching feature broke old style switch expression

https://github.com/rds1983/StbImageSharp/blob/master/src/StbImageSharp/PngDecoder.cs#L714

Doesn't compile anymore

  PngDecoder.cs(714, 38): [CS1003] Syntax error, ':' expected
  PngDecoder.cs(714, 70): [CS1002] ; expected
  PngDecoder.cs(714, 70): [CS1513] } expected
  PngDecoder.cs(718, 39): [CS1003] Syntax error, ',' expected
  PngDecoder.cs(774, 39): [CS1003] Syntax error, ',' expected
  PngDecoder.cs(793, 39): [CS1003] Syntax error, ',' expected
  PngDecoder.cs(842, 39): [CS1003] Syntax error, ',' expected
  PngDecoder.cs(878, 39): [CS1003] Syntax error, ',' expected

[RussKeldorph]

@gafter @jaredpar Does this belong in dotnet/roslyn?

[jaredpar]

@gafter can you verify this is a dupe of the switch bugs you've already fixed?

[gafter]

@jaredpar I do not believe this has been fixed

[alrz]

Looks like a dupe for https://github.com/dotnet/roslyn/issues/33208

[gafter]

Fixed in https://github.com/dotnet/roslyn/pull/33279 for dev16.0

[gafter]

As a workaround, declare a named local constant to hold the constant value you are using for the switch case.