[DeadCode] Add RemoveRedundantTypeCheckRector

[TomasVotruba]

Removes is_<type>() check that can never fail, because the type is already known.

Two shapes are handled.

1) null === compare + negated type check - real-world case on getSecurity(): ?string

 $securityExpression = $operation->getSecurity();
-if (null === $securityExpression || ! is_string($securityExpression)) {
+if (null === $securityExpression) {
     return;
 }

Once null is excluded, is_string() on a ?string is always true, so the negated check is dead. The condition narrows to the first one.

2) truthy check + type check

 public function buildWhereClauseFromArray($query, array $clauses, $expr = null)
 {
-    if ($clauses && is_array($clauses)) {
+    if ($clauses) {

$clauses is typed array, so is_array() can never fail.

Handles is_string, is_int/is_integer/is_long, is_float/is_double, is_bool, is_array, is_object.

Skipped:

// wider union - is_string() can still fail on int
if (null === $value || ! is_string($value)) {
}

// wider union - is_array() can still fail on string
if ($value && is_array($value)) {
}

// untyped param
public function run($value)
{
    if (null === $value || ! is_string($value)) {
    }
}

// different variable
if (null === $value || ! is_string($anotherValue)) {
}

Registered in DeadCodeLevel.

Includes #8308 as its first commit, as CI on main is currently red on a stray fixture file; the diff shrinks once that is merged.

[samsonasik]

This should use getNativeType(), ensure type via @param docblock skipped, eg:

/**
 * @param ?string $p
 */
function p($p) {

}

Also, there is ExprAnalyzer::isNonTypedFromParam() check for it

rector-src/src/NodeAnalyzer/ExprAnalyzer.php

Line 142 in 2a551e7

public function isNonTypedFromParam(Expr $expr): bool

[TomasVotruba]

Good catch, switched both branches to getNativeType() and added the ExprAnalyzer::isNonTypedFromParam() bail-out. Two skip fixtures cover it:

/**
 * @param ?string $value
 */
public function run($value): void
{
    if (null === $value || ! is_string($value)) {
        return;
    }
}

/**
 * @param mixed[] $clauses
 */
public function run($clauses): void
{
    if ($clauses && is_array($clauses)) {
        return;
    }
}

[TomasVotruba]

Good catch, thank you 👍