`Tracking:` Compiler debuggability improvements

[vzarytovskii]

During a compiler debugging session with @dsyme, we've identified a few points which need improvements:

• reqdTy (may TType instances) is showed as solved with no information, show solution when possible (possibly, show solution depth).

• NOTE: range's ToString will go to the filesystem and read the file. We can also reduce the text (10 characters?)

• Debugger is slow expanding object with bunch of properties (for example TType).

• Search codebase for ToString, have them consistent (having a simple string representing the type).

• Putting .ToString() with simpler info, consistently across types, rather than type name to:

  • TyparFlags
  • XmlDoc
  • CallerArg
  • CalledArg
  • AssignedCalledArg
  • cenv, TcEnv (inconsistent ToString()), TcGlobals, TcImports, TcState
  • DispayEnv, NameResolutionEnv should deliver a simple string, instead of %A
  • AccessorDomain, AccessibleFrom, CompPath - simpler ToString().
  • ... review types of MethodCalls.fs.
  • Review all of Syn* types.
  • Review test framework ToStrings (e.g. CompilationSource and CompilationUnit).

• Consider putting DebuggerStepThrough (helps debugging experience by not stepping into functions/methods), DebuggerHidden (hide stack frames) or DebuggerNonUserCode.

  • We need to review current compiler stacktraces and remove higher-order functions, for example:
    • DiagnosticLogger.fs - TryD, MapD, MapD.loop, MapCombineTDC2D, MapCombineTDCD StackGuard.Guard and others.
    • ConstraintSolver - CollectThenUndoOrCommit

• Consider adding NonUserCode to the library functions (like map, fold, etc.)? This may complicate debugging FSharp.Core itself.

• Consider using DebuggerHidden and/or NonUserCode on StartWithContinuationsUsingDispatchInfo, StartWithContinuations and StartImmediate.

• Make _FullList null if the length is <= ListDebugViewMaxLength:

  [<DebuggerBrowsable(DebuggerBrowsableState.Collapsed)>]
          member x._FullList = items (count l 0 ListDebugViewMaxFullLength)
  

[auduchinok]

NOTE: range's ToString will go to the filesystem and read the file. We can also reduce the text (10 characters?)

It can be very handy when debugging something parser-related, please leave a least some way to keep it like this.

[dsyme]

It can be very handy when debugging something parser-related, please leave a least some way to keep it like this.

You we should add a debug property with full text