[phpstan-bot]

Summary

A match (true) whose last arm is a call with @phpstan-assert-if-true was reported as "Match expression does not handle remaining value: true", even though the earlier arms had already narrowed the subject to the asserted type. is_float() and friends work in the same position because their stub's conditional return type (($value is float ? true : false)) resolves the call to true. A user-defined asserted method stayed bool, even though PHPStan already reports it as "will always evaluate to true".

This change pins a boolean call with conditional asserts to true/false whenever the argument types already decide the assertion. It covers functions, methods, static methods and nullsafe method calls, and -if-false as well as -if-true. It also fixes the same problem with if/elseif chains, which wrongly reported "should return string but return statement is missing".

Changes

• src/Rules/Comparison/ImpossibleCheckTypeHelper.php: new hasConditionalAsserts() and resolveConditionalAssertReturnType(). The latter reuses findSpecifiedType() (the verdict behind the ImpossibleCheckType* rules) and only touches non-constant boolean return types.
• src/Analyser/ExprHandler/FuncCallHandler.php, MethodCallHandler.php, StaticCallHandler.php: the type callback applies that verdict after resolveReturnType() when the callee has conditional asserts. The flag is computed once per walk, so calls without asserts pay nothing extra. The call's own ExpressionResult is read through a weak storage reference, the same pattern FuncCallHandler already uses for in_array()/array_key_exists().
• turbo-ext/src/FuncCallHandler.cpp, MethodCallHandler.cpp, StaticCallHandler.cpp, CallHandlerSupport.h, generated/{MethodCallHandler,StaticCallHandler}.h: native mirror of the above (new constructor dependency, extra type-callback captures, shared hasConditionalAsserts / weak-reference / helper-call functions in CallHandlerSupport.h).

Analogous cases probed:

• Fixed: functions, static methods, @phpstan-assert-if-false with match (false), negated !Type asserts, nullsafe ?-> calls, and if/elseif missing-return detection.
• Left as bool on purpose: asserts targeting $this->property, first-class callables ($f = $obj->isX(...)), unconditional @phpstan-assert and equality (=Type) asserts. The ImpossibleCheckType* rules don't decide these either, so behaviour stays consistent.

Root cause

For a call, "the check is already decided" was known in two places that didn't talk to each other. The ImpossibleCheckType* rules worked it out from the call's narrowing (findSpecifiedType()). The call's return type only reflected it when the callee declared a conditional return type, which built-in type checks do through stubs and @phpstan-assert-if-* methods don't. Every consumer of the return type was therefore blind to it: match exhaustiveness (hasAlwaysTrueCond), dead-branch and missing-return detection. Now the return type reads the same verdict.

Test

• tests/PHPStan/Rules/Comparison/data/bug-11374.php: the playground reproducer, unchanged. No match.unhandled errors any more; the existing "always true" reports are still expected.
• tests/PHPStan/Rules/Comparison/data/bug-11374-2.php: functions, static methods, -if-false + match (false), and a still-unhandled case (float|int|string) that must keep reporting.
• tests/PHPStan/Rules/Missing/data/bug-11374.php: if/elseif chains over asserted methods, static methods and functions, plus one that must still report the missing return.
• tests/PHPStan/Analyser/nsrt/bug-11374.php: assertType() for decided, undecided, -if-false, negated, static, function, unconditional-assert and equality-assert calls.

All of these fail without the fix. make tests and make phpstan pass. With the turbo extension built and loaded, the full test suite, smoke.php, signature-parity.php, side-by-side.php and the walk-trace.php differential (identical traces) all pass.

Fixes phpstan/phpstan#11374

[VincentLanglet]

PHPStan check fails on PHP 7.4
https://github.com/phpstan/phpstan-src/actions/runs/41836974206/job/126598295500?pr=6947