Hi, when compiling a project today I ran into this:

compile [afPillow]
  Compile [afPillow]
    FindSourceFiles [20 files]
ERR: Internal compiler error
sys::NullErr: Coerce to non-null
  fan.sys.NullErr.makeCoerce (NullErr.java:38)
  compiler::Parser.simpleType (Parser.fan:2207)
  compiler::Parser.ctype (Parser.fan:2104)
  compiler::Parser.ctype (Parser.fan)
  compiler::Parser.tryType (Parser.fan:2078)
  compiler::Parser.termBaseExpr (Parser.fan:1524)
  compiler::Parser.termExpr (Parser.fan:1500)
  compiler::Parser.termExpr (Parser.fan)
  compiler::Parser.unaryExpr (Parser.fan:1471)
  compiler::Parser.parenExpr (Parser.fan:1405)
  compiler::Parser.multExpr (Parser.fan:1390)
  compiler::Parser.addExpr (Parser.fan:1378)
  compiler::Parser.rangeExpr (Parser.fan:1361)
  compiler::Parser.relationalExpr (Parser.fan:1330)
  compiler::Parser.equalityExpr (Parser.fan:1296)
  compiler::Parser.condAndExpr (Parser.fan:1276)
  compiler::Parser.condOrExpr (Parser.fan:1256)
  compiler::Parser.ifExpr (Parser.fan:1208)
  compiler::Parser.assignExpr (Parser.fan:1189)
  compiler::Parser.assignExpr (Parser.fan)
  compiler::Parser.expr (Parser.fan:1178)
  compiler::Parser.localDefStmt (Parser.fan:944)
  compiler::Parser.exprOrLocalDefStmt (Parser.fan:882)
  compiler::Parser.stmt (Parser.fan:855)
  compiler::Parser.stmtOrBlock (Parser.fan:822)
  compiler::Parser.block (Parser.fan:803)
  compiler::Parser.methodDef (Parser.fan:704)
  compiler::Parser.slotDef (Parser.fan:434)
  compiler::Parser.typeDef (Parser.fan:233)
  compiler::Parser.parse (Parser.fan:48)
  25 More...
BUILD FAILED [527ms]!

Which wasn't very helpful!

The Parser code in question looks like:

private CType simpleType() {
  ...

  // if more then one, first try to exclude those internal to other pods
  if (types.size > 1) types = types.exclude |t| { t.isInternal && t.pod.name != compiler.pod.name }

  // if more then one its ambiguous (use errReport to avoid suppression)
  if (types.size > 1)
    errReport(CompilerErr("Ambiguous type: " + types.join(", "), loc))

  // got it
  return types.first   // <-- line 2207
}

If all the types are internal to other pods then types becomes empty and types.first returns null resulting in the NullErr.

So my solution was to re-compile the compiler, adding the following to Parser.simpleType():

private CType simpleType() {
  ...

  // if more then one, first try to exclude those internal to other pods
  if (types.size > 1) types = types.exclude |t| { t.isInternal && t.pod.name != compiler.pod.name }

  // ---- PATCH START ----
  // all types were internal to other pods
  if (types.isEmpty)
    throw err("Unknown type '$id'", loc)
  // ---- PATCH END ------

  // if more then one its ambiguous (use errReport to avoid suppression)
  if (types.size > 1)
    errReport(CompilerErr("Ambiguous type: " + types.join(", "), loc))

  // got it
  return types.first
}

and now I get the following sane error msg:

compile [afPillow]
  Compile [afPillow]
    FindSourceFiles [20 files]
C:\Projects\Fantom-Factory\Pillow\fan\public\Pages.fan(58,12): 
Ambiguous type: afIoc::Utils, afEfanXtra::Utils, afBedSheet::Utils, afConcurrent::Utils
BUILD FAILED [790ms]!

Hooray!

Before integrating that patch I'd also like to get a test case that reproduces it we can add to the testCompiler suite. What did the code look like that caused that? I can't make it happen

What did the code look like that caused that?

Oh yeah, I forgot to add the important stuff!

If you install IoC then the following reproduces the null Err

using afIoc
using afPlastic

class Which {
    Void main() {
        Utils.getLog(this.typeof)
    }
}

Just run it as a script:

D:\Temp\fantom>fan Which.fan

ERROR: cannot compile script
sys::NullErr: Coerce to non-null
  fan.sys.NullErr.makeCoerce (NullErr.java:38)
  compiler::Parser.simpleType (Parser.fan:2207)
  compiler::Parser.ctype (Parser.fan:2104)
  compiler::Parser.ctype (Parser.fan)
  ...

Both IoC and Plastic have a Utils class with a getLog() method.

Hi, I ran into this issue again today.

C:\Projects\CodeExplorer>fan build.fan

compile [mmCodeExplorer]
  Compile [mmCodeExplorer]
    FindSourceFiles [18 files]
ERR: Internal compiler error
sys::NullErr: Coerce to non-null
  fan.sys.NullErr.makeCoerce (NullErr.java:38)
  compiler::Parser.simpleType (Parser.fan:2208)
  compiler::Parser.ctype (Parser.fan:2105)
  compiler::Parser.ctype (Parser.fan)
  compiler::Parser.tryType (Parser.fan:2079)
  compiler::Parser.termBaseExpr (Parser.fan:1525)
  compiler::Parser.termExpr (Parser.fan:1501)
  compiler::Parser.termExpr (Parser.fan)
  compiler::Parser.unaryExpr (Parser.fan:1472)
  compiler::Parser.parenExpr (Parser.fan:1406)
  ...
  ...

I re-patched my compiler::Parser class with the code in the first post and now I get:

C:\Projects\CodeExplorer>fan build.fan

compile [mmCodeExplorer]
  Compile [mmCodeExplorer]
    FindSourceFiles [18 files]
C:\Projects\Nigel\CodeExplorer\fan\DataMigration.fan(178,18): Ambiguous type: afIocConfig::ErrMsgs, afButter::ErrMsgs
BUILD FAILED [587ms]!

The line causing the compilation error was:

using afButter
using afIocConfig

...

throw Err(ErrMsgs.noMatch)

With ErrMsgs being an internal class in both afIocConfig and afButter.

With ErrMsgs being an internal class in both afIocConfig and afButter.

Yeah with that info I was able to reproduce it too. Thanks. Pushed a fix