Do not activate power assertions when a single union member containing a type constraint fails#1462
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HT154 wants to merge 2 commits intoapple:mainfrom
Open
Do not activate power assertions when a single union member containing a type constraint fails#1462HT154 wants to merge 2 commits intoapple:mainfrom
HT154 wants to merge 2 commits intoapple:mainfrom
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…g a type constraint fails
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HT154
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Mar 5, 2026
holzensp
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Mar 10, 2026
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Not the prettiest, but I can't think of something prettier. No blockers.
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| localContext.setInTypeTest(wasInTypeTest); | ||
| if (VmContext.get(this).getPowerAssertionsEnabled() | ||
| && (!wasInTypeTest || localContext.hasActiveTracker())) { | ||
| for (var i = 0; i < elementTypeNodes.length; i++) { | ||
| try { | ||
| elementTypeNodes[i].executeEagerly(frame, value); | ||
| } catch (VmTypeMismatchException e) { | ||
| typeMismatches[i] = e; | ||
| } | ||
| } | ||
| } |
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My spidey senses tingle at the lack of DRYness. I don't want to insist on DRYness per se, but would like to ask the question out loud; worth a private static helper or similar.
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This is certainly possible, but I'm hesitant to do it without more context here, i.e. why does executeLazily use @ExplodeLoop but executeEagerly does not? Was this not already DRY'd up because of some optimization?
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Prior to this change, this code would activate powers assertions / instrumentation permanently:
This is because the
contains("a")constraint would fail, triggering power assertions, but the subsequent check of the union'scontains("b")branch would succeed.As observed in #1419, once instrumentation is enabled, all subsequent evaluation slows significantly.
As with #1419, the fix here is to disable power assertions via
VmLocalContextuntil we know that all union members failed type checking; then, each member is re-executed with power assertions allowed to provide the improved user-facing error.