Determine optimal formatting for ternary arguments

[sharwell]

The formatter doesn't produce readable code from the following expression:

roslyn/src/Compilers/CSharp/Portable/Symbols/Source/SourceMemberContainerSymbol_ImplementationChecks.cs

Lines 1040 to 1054 in b4c9469

	CheckValidNullableMethodOverride(overridingMethod.DeclaringCompilation, overriddenMethod, overridingMethod, diagnostics,
	checkReturnType ?
	(diagnostics, overriddenMethod, overridingMethod, location) => diagnostics.Add(ErrorCode.WRN_NullabilityMismatchInReturnTypeOnOverride, location) :
	(Action<DiagnosticBag, MethodSymbol, MethodSymbol, Location>)null,
	checkParameters ?
	(diagnostics, overriddenMethod, overridingMethod, overridingParameter, location) =>
	{
	diagnostics.Add(
	ErrorCode.WRN_NullabilityMismatchInParameterTypeOnOverride,
	location,
	new FormattedSymbol(overridingParameter, SymbolDisplayFormat.ShortFormat));
	}
	:
	(Action<DiagnosticBag, MethodSymbol, MethodSymbol, ParameterSymbol, Location>)null,
	overridingMemberLocation);

However, it's not clear how this code should be formatted such that the result is readable.

[JoeRobich]

If we could convince the world to insert newlines before the ternary operator...

 CheckValidNullableMethodOverride(overridingMethod.DeclaringCompilation, overriddenMethod, overridingMethod, diagnostics, 
                                  checkReturnType
                                      ? (diagnostics, overriddenMethod, overridingMethod, location) => diagnostics.Add(ErrorCode.WRN_NullabilityMismatchInReturnTypeOnOverride, location)
                                      : (Action<DiagnosticBag, MethodSymbol, MethodSymbol, Location>)null, 
                                  checkParameters
                                      ? (diagnostics, overriddenMethod, overridingMethod, overridingParameter, location) => 
                                      { 
                                          diagnostics.Add( 
                                              ErrorCode.WRN_NullabilityMismatchInParameterTypeOnOverride, 
                                              location, 
                                              new FormattedSymbol(overridingParameter, SymbolDisplayFormat.ShortFormat)); 
                                      } 
                                      : (Action<DiagnosticBag, MethodSymbol, MethodSymbol, ParameterSymbol, Location>)null, 
                                  overridingMemberLocation);

or to extract locals when code get too complex (for some definition of complex).

📎 "Hi, it looks like you are trying to do too much. Would you like some help extracting locals?"

[sharwell]

The current formatter implementation won't allow the : to be indented after the }. That seems like an oversight.