Imported From: https://issues.scala-lang.org/browse/SI-9235?orig=1
Reporter: Carl Chatfiled (carlchatfield)
Affected Versions: 2.11.5
See #9781
Duplicates #8763

@adriaanm said:
Running under -Xprint:typer points towards https://github.com/scala/scala/blob/2.11.x/src/compiler/scala/tools/nsc/typechecker/Typers.scala#L4617

It looks like the error in the RHS of the val (qualqual) is masked by evalOnce's wrapping?

      <synthetic> val ev$1: A = Test.this.as.apply(<undefined: error>);
      ev$1.a_=(ev$1.a.+(1))

@adriaanm said:
When running under -Ytyper-debug, this looks dubious -- an application to an error-typed arg should be error-typed:

|    |    |    |-- as(<undefined: error>).a EXPRmode-POLYmode-QUALmode (site: method test in Test) 
|    |    |    |    |-- String => A EXPRmode-POLYmode-QUALmode (site: method test in Test) 
|    |    |    |    |    |-- as.apply BYVALmode-EXPRmode-FUNmode-POLYmode (silent: method test in Test) 
|    |    |    |    |    |    \-> (v1: String)A
|    |    |    |    |    \-> A
|    |    |    |    \-> Int

@liff said:
I think this is duplicate with #9781. The example results in error: not found: value undefined instead of compiler crash on 2.12.x.

@som-snytt said (edited on Nov 1, 2016 6:23:13 AM UTC):
I didn't notice these issues until just now. By coincidence I just closed another duplicate because there's a PR on 2.11, scala/scala#5454

Did I already know that? (Yes.) It's all ancient history now. It was before the rains returned.