Class ProvenContainerChange

java.lang.Object

org.ek9lang.compiler.phase5.ProvenContainerChange

final class ProvenContainerChange
extends Object

THE reading of whether something may change the OBJECT an Optional / Result / Iterator variable refers to, so that a proof that its get(), ok(), error() or next() is safe (E08030) no longer holds: D66 ("a call that is not pure forgets what it can reach", Steve 2026-10-21) applied to the safe-access proofs. It answers from the same readings the value tracker forgets by - ObjectSharing for one occurrence of a name, ProgramCodeSites for the places code of the program's own runs, and the tracker's own sharing, escape and from-outside record (ValueTrackingAnalyzer.mayBeChangedThrough(ISymbol, ISymbol), ValueTrackingAnalyzer.mayBeChangedByCall(ISymbol, boolean, Collection)). Never a second list of the ways an object can change.

Where the tracker is not following a callable (it records nothing outside one) nothing is known about who shares what, so every change counts as a change to every container: it fails closed.

Before 2026-11-10 a proof survived everything but a store to the variable itself (E08040): if name? then forget(name) with a forget that empties its argument (target :=: Optional()), then name.get() compiled clean and threw 'No such element'.

Constructor Summary

Constructors

Constructor	Description
ProvenContainerChange(SymbolsAndScopes symbolsAndScopes, ValueTrackingAnalyzer valueTracker, ObjectSharing objectSharing)

Method Summary

Modifier and Type	Method	Description
(package private) boolean	byOccurrence(ISymbol occurrenceSymbol, List<ObjectSharing.Use> uses, ISymbol container, boolean sharingCounts)	May this occurrence of occurrenceSymbol - with the effects uses (ObjectSharing) - change the object container refers to? A mutating operator, a call that may change it or a holder nothing names keeping it does, through any name that may be the same object.
(package private) boolean	bySite(ProgramCodeSites.Site site, ISymbol container)	May the program code run at site (ProgramCodeSites) change the object container refers to - through a name an in-place write or an iteration changes in place, or beyond the names it is given (a call's are judged as their own occurrences)?
(package private) List<ObjectSharing.Use>	usesOf(EK9Parser.IdentifierContext occurrence, ISymbol symbol)	What one occurrence of symbol does to the object it names (ObjectSharing); for a container itself, without what is done to its views - show(name.get()) hands on the ITEM, which cannot empty the Optional (ObjectSharing.ofTheObjectItself(EK9Parser.IdentifierContext, Function)).
(package private) List<ObjectSharing.Use>	usesOf(EK9Parser.IdentifierContext occurrence, ISymbol symbol, List<ObjectSharing.Use> allUses)	As usesOf(EK9Parser.IdentifierContext, ISymbol), when every use of the occurrence (allUses, ObjectSharing.apply(EK9Parser.IdentifierContext, Function)) is already known: those, or for a container only the uses of the object itself.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ProvenContainerChange

ProvenContainerChange(SymbolsAndScopes symbolsAndScopes,
 ValueTrackingAnalyzer valueTracker,
 ObjectSharing objectSharing)

Method Details

usesOf

List<ObjectSharing.Use> usesOf(EK9Parser.IdentifierContext occurrence,
 ISymbol symbol)

What one occurrence of symbol does to the object it names (ObjectSharing); for a container itself, without what is done to its views - show(name.get()) hands on the ITEM, which cannot empty the Optional (ObjectSharing.ofTheObjectItself(EK9Parser.IdentifierContext, Function)).

usesOf

List<ObjectSharing.Use> usesOf(EK9Parser.IdentifierContext occurrence,
 ISymbol symbol,
 List<ObjectSharing.Use> allUses)

As usesOf(EK9Parser.IdentifierContext, ISymbol), when every use of the occurrence (allUses, ObjectSharing.apply(EK9Parser.IdentifierContext, Function)) is already known: those, or for a container only the uses of the object itself.

byOccurrence

boolean byOccurrence(ISymbol occurrenceSymbol,
 List<ObjectSharing.Use> uses,
 ISymbol container,
 boolean sharingCounts)

May this occurrence of occurrenceSymbol - with the effects uses (ObjectSharing) - change the object container refers to? A mutating operator, a call that may change it or a holder nothing names keeping it does, through any name that may be the same object. Making ANOTHER name share the object (ObjectSharing.Kind.SHARED) changes nothing by itself; it counts only when sharingCounts - for a region read ahead of the walk, where the new name's later changes are not yet recorded as the same object's.

bySite

boolean bySite(ProgramCodeSites.Site site,
 ISymbol container)

May the program code run at site (ProgramCodeSites) change the object container refers to - through a name an in-place write or an iteration changes in place, or beyond the names it is given (a call's are judged as their own occurrences)?