Compare constant scalars refined by accessory types against other union members in TypeCombinator::union()

phpstan-baseline.neon

@@ -1678,7 +1678,7 @@ parameters:
 		-
 			rawMessage: Doing instanceof PHPStan\Type\IntersectionType is error-prone and deprecated.
 			identifier: phpstanApi.instanceofType
-			count: 7
+			count: 8
 			path: src/Type/TypeCombinator.php
 
 		-

src/Type/TypeCombinator.php

@@ -420,7 +420,10 @@ public static function doUnion(Type ...$types): Type
 		$enumCaseTypes = [];
 		$integerRangeTypes = [];
 		for ($i = 0; $i < $typesCount; $i++) {
-			if ($types[$i]->isConstantScalarValue()->yes()) {
+			// a constant scalar refined by an accessory type ('Foo'&hasMethod(bar))
+			// stays with the other types so it is compared against the plain
+			// constant scalars and other refinements of the same value
+			if (!$types[$i] instanceof IntersectionType && $types[$i]->isConstantScalarValue()->yes()) {
 				$type = $types[$i];
 				$scalarTypes[get_class($type)][$type->describe(VerbosityLevel::cache())] = $type;
 				unset($types[$i]);

tests/PHPStan/Analyser/nsrt/bug-15591.php

@@ -0,0 +1,42 @@
+<?php declare(strict_types = 1);
+
+namespace Bug15591;
+
+use function PHPStan\Testing\assertType;
+
+class Foo
+{
+}
+
+function test(): void
+{
+	$class = Foo::class;
+	foreach (['m1', 'm2', 'm3', 'm4', 'm5', 'm6', 'm7', 'm8', 'm9', 'm10', 'm11', 'm12'] as $method) {
+		if (method_exists($class, $method)) {
+		}
+	}
+	assertType("'Bug15591\\\\Foo'", $class);
+}
+
+function testStraightLine(): void
+{
+	$class = Foo::class;
+	if (method_exists($class, 'm1')) {
+		assertType("'Bug15591\\\\Foo'&hasMethod(m1)", $class);
+	}
+	assertType("'Bug15591\\\\Foo'", $class);
+	if (method_exists($class, 'm2')) {
+		assertType("'Bug15591\\\\Foo'&hasMethod(m2)", $class);
+	}
+	assertType("'Bug15591\\\\Foo'", $class);
+}
+
+function testProperty(): void
+{
+	$class = Foo::class;
+	if (property_exists($class, 'p1')) {
+	}
+	if (property_exists($class, 'p2')) {
+	}
+	assertType("'Bug15591\\\\Foo'", $class);
+}

tests/bench/data/bug-15591.php

@@ -0,0 +1,16 @@
+<?php declare(strict_types = 1);
+
+namespace MethodExistsLoopRepro;
+
+class Foo
+{
+}
+
+function test(): void
+{
+	$class = Foo::class;
+	foreach (['m1', 'm2', 'm3', 'm4', 'm5', 'm6', 'm7', 'm8', 'm9', 'm10', 'm11', 'm12'] as $method) {
+		if (method_exists($class, $method)) {
+		}
+	}
+}

turbo-ext/src/TypeCombinator.cpp

@@ -1038,8 +1038,11 @@ class TypeCombinator
 		Level cacheLevel(PT_LC("cache"));
 		for (size_t i = 0; i < typesCount; i++) {
 			zval *type = types[i].raw();
-			zend_long isConstantScalarValue = callTrinary(type, PT_LC("isconstantscalarvalue"));
-			PT_FAIL_IF_NEG(isConstantScalarValue);
+			zend_long isConstantScalarValue = PT_TRI_NO;
+			if (!isInstance(type, pt_ce_intersection_type)) {
+				isConstantScalarValue = callTrinary(type, PT_LC("isconstantscalarvalue"));
+				PT_FAIL_IF_NEG(isConstantScalarValue);
+			}
 			if (isConstantScalarValue == PT_TRI_YES) {
 				zv::Val description = describe(type, cacheLevel);
 				zend_string *key = describedKey(description);