scalac compiler and scala REPL should treat shebangs as comments

[scabug]

For example, :load <script>.scala currently triggers an error in the scala REPL, but not when the same file is run with scala <script>.scala or ./<script>.scala. That seems a bit silly, when the shebang could simply be treated as a comment.

It would be a great convenience if the scalac compiler and scala REPL treated shebangs (#!/usr/bin/env scala) on the first line of a scala file as a comment.

Use cases:

• Flexibly convert between script-style and compile-style code
• Better first-time experience for Unix coders
• Better Windows support for Unix-style code

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-8660?orig=1
Reporter: Andrew Pennebaker (mcandre)
Affected Versions: 2.11.1
Duplicates #5179

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@som-snytt said:
One thing to consider is that scripts and REPL code is wrapped differently (though that is fixable) so there are differences in semantics which could degrade first-time experiences.

Maybe add :paste -script some.scala.

[scabug]

@som-snytt said:
The scalac half of the proposal is a duplicate which requires discussion that hasn't materialized.

But maybe we can just get rid of scalac and give the scala tool another dose of intuition to do the right thing with whatever we feed it: scripts, compilation units, ASTs, tests, benchmarks, jars.

[SethTisue]

this is out of scope now that Scala-CLI exists (https://scala-cli.virtuslab.org)