Integrated: 8325859: Potential information loss during type inference

[Vicente Romero]

On Fri, 2 May 2025 17:18:05 GMT, Vicente Romero <vromero at openjdk.org> wrote:

> When an inference context (`IC`) is minimized, the minimized inference context (`MIC`) contains a proper subset of `IC's` inference vars (`IC_IV`). In other words there will be at least one inference variable `T` that belongs to `IC_IV` which doesn't belong to the minimized context inference variable's set (`MIC_IV`). MIC can be propagated to another inference context (AIC) as part of the type inference algo. If at any moment a type containing `T` needs, for example, to be instantiated `AIC` won't be able to perform that operation as it lacks the information to realize that `T` is a free variable it was supposed to know about hadn't a minimization step been performed. This PR is proposing to fix this issue without reducing the universe of inference contexts we apply the minimization algo to.
> 
> We are basically proposing to add a field to class InferenceContext which will be supplementary inference context that can be used to look for additional information if necessary. Also when registering a free type listener to an inference context, it could be that it won't be registered in the inference context the client could expect but in a supplementary inference context if it is found out that it contains and instantiation to all the free variables related to the listener. See also some comments inlined in the code,
> 
> TIA

This pull request has now been integrated.

Changeset: a4f66f54
Author:    Vicente Romero <vromero at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/a4f66f5439f7fe585bd3664b7f2ceec23234e554
Stats:     77 lines in 3 files changed: 73 ins; 0 del; 4 mod

8325859: Potential information loss during type inference

Reviewed-by: mcimadamore

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PR: https://git.openjdk.org/jdk/pull/25011