Bug in code generation

[MeAmAnUsername]

Summary
A bug in code generation, possibly due to the if-else with nested generics

Todo

• Make a test
• Fix bug

Description
Example code:

data Fruit = foreign java Fruit {}
data Orange <: Fruit = foreign java Orange {}
data Banana <: Fruit = foreign java Banana {}

data Box[T] = foreign java Box {
  func get() -> T
}
func Box[T]() -> Box[T] = foreign java constructor Box

func mergeTypeArg() -> unit = {
  val box1: Box[Orange] = Box[Orange]();
  val box2: Box[Banana] = Box[Banana]();
  val box: Box[_ <: Fruit] = if (true) box1 else box2;
  unit
}

Given: run code generation (Spoofax > Generate > Java AST) on the example code
Expected: code generation finishes successfully.
Actual: code generation fails with an error:

13:38 | INFO  | stderr                         - start p2j-ast-def: "mergeTypeArg"{TermIndex("src/main/test.pie",125)}
13:38 | ERROR | o.m.s.e.t.TransformJob         - Transformation failed for eclipse:///test_ground/src/main/test.pie
org.metaborg.core.transform.TransformException: Invoking Stratego strategy generate-java-file-ast failed at term:
	Scope(".", "s_common_instance_1644-196")
Stratego trace:
	generate_java_file_ast_0_0
	with_1_1
	p2j_ast_0_0
	with_1_1
	dr_scope_1_1
	dr_scope_1_1
	dr_scope_1_1
	filter_1_0
	with_1_1
	dr_scope_1_1
	dr_scope_1_1
	p2j_ast_pie_func_impl_body_0_0
	with_1_1
	map_1_0
	try_p2j_ast_exp_0_0
	pie_try_debug_1_1
	s11
	with_1_1
	try_p2j_ast_exp_0_0
	pie_try_debug_1_1
	s11
	with_1_1
	p2j_ast_type_sig_0_0
	with_1_1
	pie_get_context_0_1
	with_1_1 <==
Internal error: 'with' clause failed unexpectedly in 'pie-get-context'
	at org.metaborg.spoofax.core.transform.StrategoTransformer.transform(StrategoTransformer.java:163)
	at org.metaborg.spoofax.core.transform.StrategoTransformer.transform(StrategoTransformer.java:86)
	at org.metaborg.spoofax.core.transform.StrategoTransformer.transform(StrategoTransformer.java:1)
	at org.metaborg.core.transform.TransformService.transform(TransformService.java:88)
	at org.metaborg.spoofax.eclipse.transform.TransformJob.transform(TransformJob.java:145)
	at org.metaborg.spoofax.eclipse.transform.TransformJob.transformAll(TransformJob.java:120)
	at org.metaborg.spoofax.eclipse.transform.TransformJob.run(TransformJob.java:80)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)
Caused by: org.spoofax.interpreter.core.InterpreterErrorExit: Internal error: 'with' clause failed unexpectedly in 'pie-get-context'
	at org.strategoxt.lang.InteropSDefT.evaluate(InteropSDefT.java:194)
	at org.strategoxt.lang.InteropSDefT.evaluate(InteropSDefT.java:183)
	at org.strategoxt.lang.InteropSDefT$StrategyBody.evaluate(InteropSDefT.java:245)
	at org.strategoxt.lang.InteropSDefT$StrategyBody.eval(InteropSDefT.java:238)
	at org.spoofax.interpreter.stratego.Strategy.evaluate(Strategy.java:86)
	at org.spoofax.interpreter.core.Interpreter.evaluate(Interpreter.java:105)
	at org.spoofax.interpreter.core.Interpreter.invoke(Interpreter.java:80)
	at org.strategoxt.HybridInterpreter.invoke(HybridInterpreter.java:458)
	at org.metaborg.spoofax.core.stratego.StrategoCommon.invoke(StrategoCommon.java:148)
	at org.metaborg.spoofax.core.transform.StrategoTransformer.transform(StrategoTransformer.java:161)
	... 7 common frames omitted