Language: trait insteadof parent class compile error wrong — Zend "not a trait" (Zend/zend_compile.c)

[PurHur]

Category

language · php-src-strict · traits · compile-time error text

Problem

Using a parent class name in a trait insteadof clause is a compile-time error in php-src. This compiler emits a generic Could not find trait P message instead of Zend's explicit "Class P is not a trait, Only traits may be used in 'as' and 'insteadof' statements".

Repro	Zend 8.2+	VM/JIT compile (2026-08-18 @ 2f0c85a98d)
class P{}; trait T{}; class C extends P { use T { T::m insteadof P; } }	Fatal: Class P is not a trait…	Could not find trait P

Workers/compliance diff on error text, not just failure presence.

php-src reference

• php/php-src Zend/zend_compile.c — zend_compile_traits(), zend_trait_method_compatibility_check()

PHP implementation target

• lib/ trait compilation / conflict resolution — when insteadof/as operand resolves to a class that is not a trait, emit Zend message verbatim
• Keep logic in PHP compile pipeline; no new C runtime branches

Repro

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_trait_insteadof_parent.php 2>&1 | head -1'
./script/docker-exec.sh -- bash -lc 'php bin/jit.php test/repro/maintainer_gap_trait_insteadof_parent.php 2>&1 | head -1'

Done when

• Compile abort message matches Zend substring is not a trait with class name P on VM and JIT
• Compliance .phpt guard under test/compliance/cases/language/trait_insteadof_parent*.phpt asserting %is not a trait%
• php-src-strict; no php-compiler-strict shortcut

[PurHur]

claim: PHP Compiler Worker Lane C — starting this run

[PurHur]

Merged in #32134

insteadof/as operands that resolve to a declared class now match Zend zend_check_trait_usage (Class P is not a trait, Only traits may be used in 'as' and 'insteadof' statements). Folded into the #32130 unresolved-adaptation helper so unused traits still report Required Trait … wasn't added.

Verification:

• php bin/vm.php / php bin/jit.php on test/repro/maintainer_gap_trait_insteadof_parent.php → that message, exit 255
• ./script/phpunit.sh --filter 'TraitInsteadofParentVMTest|TraitInsteadofParentJITTest|TraitDiamondInsteadofRequiredNotAddedVMTest|TraitDiamondInsteadofRequiredNotAddedJITTest|TraitAdaptationTest|MissingTraitFatalQuotesTest' → OK (25 tests, 44 assertions)

Did not run full harness / ci-local / north-star5-verify --strict.