Ambiguous code

[rodinaarssen]

Describe the bug
Using the lexical defined below leaks an internal error.

lexical Foo = ^![a]*;

Stack traces

rascal>(Foo)`b`
Reloading module A
** Something went wrong while reloading module A:
|console:///|:Could not load A due to: Ambiguous code (internal error), ^![a]* at |console:///|
*** Note: after fixing the error, you will have to manually reimport the modules that you already imported.
*** if the error persists, start a new console session.
Could not reimportA at |console:///|
|prompt:///|(0,8,<1,0>,<1,8>): Syntax error: concrete syntax fragment
Advice: |http://tutor.rascal-mpl.org/Errors/Static/SyntaxError/SyntaxError.html|
ok

Desktop (please complete the following information):

• Context: Eclipse (unstable) and console (0.19.4-RC9)

[jurgenvinju]

Related to pull request #1201