Language: diamond trait insteadof compile error wrong — Zend "Required Trait … wasn't added" (Zend/zend_compile.c)

[PurHur]

Category

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

Problem

Diamond trait graphs that require insteadof to pick a single DA::m provider should fail at compile time with Zend's "Required Trait DA wasn't added to DD" when the resolution is invalid. This compiler reports Could not find trait DA, hiding the real conflict reason.

Repro	Zend 8.2+	VM/JIT compile (2026-08-18 @ 2f0c85a98d)
trait DA{}; trait DB{use DA;}; trait DC{use DA;}; class DD{use DB,DC{DA::m insteadof DB,DC;}}	Fatal: Required Trait DA wasn't added to DD	Could not find trait DA

Distinct from #32129 (parent class in insteadof); same error-reporting subsystem.

php-src reference

• php/php-src Zend/zend_compile.c — trait precedence / alias registration (zend_register_trait_aliases, required-trait checks)

PHP implementation target

• lib/ trait alias registration — surface Zend required-trait message when alias names a method provider not directly used on the class
• PHP compile path only; shrink misleading generic trait lookup errors

Repro

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

Done when

• Compile abort matches Zend substring Required Trait DA wasn't added on VM and JIT
• Compliance .phpt guard under test/compliance/cases/language/trait_diamond_insteadof*.phpt
• php-src-strict; no php-compiler-strict shortcut

[PurHur]

claim: Worker lane A — starting this run

[PurHur]

merged: #32133 (9b97cb27136c)

Diamond insteadof now matches Zend zend_check_trait_usage: Required Trait DA wasn't added to DD (not Could not find trait DA). Unknown names still say Could not find trait.

Verification:

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_trait_diamond_insteadof.php'
EXIT:255
Required Trait DA wasn't added to DD

./script/docker-exec.sh -- bash -lc 'php bin/jit.php test/repro/maintainer_gap_trait_diamond_insteadof.php'
EXIT:255
Required Trait DA wasn't added to DD

./script/phpunit.sh --filter 'TraitDiamondInsteadofRequiredNotAdded|TraitAdaptationTest|MissingTraitFatalQuotesTest'
OK (21 tests, 36 assertions)

php-src-strict; PHP composition only (lib/VM.php, lib/JIT.php, TraitCompositionConflictMessage). Not run: ci-fast.sh, full compliance suites, AOT sweep.