diff --git a/src/Analyser/EnsuredNonNullabilityResultExpression.php b/src/Analyser/EnsuredNonNullabilityResultExpression.php
index 33f94341e6..a7ed1572f8 100644
--- a/src/Analyser/EnsuredNonNullabilityResultExpression.php
+++ b/src/Analyser/EnsuredNonNullabilityResultExpression.php
@@ -3,7 +3,6 @@
 namespace PHPStan\Analyser;
 
 use PhpParser\Node\Expr;
-use PHPStan\TrinaryLogic;
 use PHPStan\Type\Type;
 
 class EnsuredNonNullabilityResultExpression
@@ -13,7 +12,6 @@ public function __construct(
 		private Expr $expression,
 		private Type $originalType,
 		private Type $originalNativeType,
-		private TrinaryLogic $certainty,
 	)
 	{
 	}
@@ -33,9 +31,4 @@ public function getOriginalNativeType(): Type
 		return $this->originalNativeType;
 	}
 
-	public function getCertainty(): TrinaryLogic
-	{
-		return $this->certainty;
-	}
-
 }
diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index c5ddd96917..91ee5eb759 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -2341,10 +2341,6 @@ public function isSpecified(Expr $node): bool
 	/** @api */
 	public function hasExpressionType(Expr $node): TrinaryLogic
 	{
-		if ($node instanceof Variable && is_string($node->name)) {
-			return $this->hasVariableType($node->name);
-		}
-
 		$exprString = $this->getNodeKey($node);
 		if (!isset($this->expressionTypes[$exprString])) {
 			return TrinaryLogic::createNo();
@@ -3437,7 +3433,7 @@ public function unsetExpression(Expr $expr): self
 		return $scope->invalidateExpression($expr);
 	}
 
-	public function specifyExpressionType(Expr $expr, Type $type, Type $nativeType, ?TrinaryLogic $certainty = null): self
+	public function specifyExpressionType(Expr $expr, Type $type, Type $nativeType): self
 	{
 		if ($expr instanceof ConstFetch) {
 			$loweredConstName = strtolower($expr->name->toString());
@@ -3471,7 +3467,6 @@ public function specifyExpressionType(Expr $expr, Type $type, Type $nativeType,
 					if ($dimType instanceof ConstantIntegerType) {
 						$types[] = new StringType();
 					}
-
 					$scope = $scope->specifyExpressionType(
 						$expr->var,
 						TypeCombinator::intersect(
@@ -3479,23 +3474,16 @@ public function specifyExpressionType(Expr $expr, Type $type, Type $nativeType,
 							new HasOffsetValueType($dimType, $type),
 						),
 						$scope->getNativeType($expr->var),
-						$certainty,
 					);
 				}
 			}
 		}
 
-		if ($certainty === null) {
-			$certainty = TrinaryLogic::createYes();
-		} elseif ($certainty->no()) {
-			throw new ShouldNotHappenException();
-		}
-
 		$exprString = $this->getNodeKey($expr);
 		$expressionTypes = $scope->expressionTypes;
-		$expressionTypes[$exprString] = new ExpressionTypeHolder($expr, $type, $certainty);
+		$expressionTypes[$exprString] = ExpressionTypeHolder::createYes($expr, $type);
 		$nativeTypes = $scope->nativeExpressionTypes;
-		$nativeTypes[$exprString] = new ExpressionTypeHolder($expr, $nativeType, $certainty);
+		$nativeTypes[$exprString] = ExpressionTypeHolder::createYes($expr, $nativeType);
 
 		return $this->scopeFactory->create(
 			$this->context,
diff --git a/src/Analyser/NodeScopeResolver.php b/src/Analyser/NodeScopeResolver.php
index 3c3acb499b..1f8fd4d8d1 100644
--- a/src/Analyser/NodeScopeResolver.php
+++ b/src/Analyser/NodeScopeResolver.php
@@ -1753,14 +1753,6 @@ private function ensureShallowNonNullability(MutatingScope $scope, Scope $origin
 		if ($isNull->yes()) {
 			return new EnsuredNonNullabilityResult($scope, []);
 		}
-
-		// keep certainty
-		$certainty = TrinaryLogic::createYes();
-		$hasExpressionType = $originalScope->hasExpressionType($exprToSpecify);
-		if (!$hasExpressionType->no()) {
-			$certainty = $hasExpressionType;
-		}
-
 		$exprTypeWithoutNull = TypeCombinator::removeNull($exprType);
 		if ($exprType->equals($exprTypeWithoutNull)) {
 			$originalExprType = $originalScope->getType($exprToSpecify);
@@ -1768,7 +1760,7 @@ private function ensureShallowNonNullability(MutatingScope $scope, Scope $origin
 				$originalNativeType = $originalScope->getNativeType($exprToSpecify);
 
 				return new EnsuredNonNullabilityResult($scope, [
-					new EnsuredNonNullabilityResultExpression($exprToSpecify, $originalExprType, $originalNativeType, $certainty),
+					new EnsuredNonNullabilityResultExpression($exprToSpecify, $originalExprType, $originalNativeType),
 				]);
 			}
 			return new EnsuredNonNullabilityResult($scope, []);
@@ -1784,7 +1776,7 @@ private function ensureShallowNonNullability(MutatingScope $scope, Scope $origin
 		return new EnsuredNonNullabilityResult(
 			$scope,
 			[
-				new EnsuredNonNullabilityResultExpression($exprToSpecify, $exprType, $nativeType, $certainty),
+				new EnsuredNonNullabilityResultExpression($exprToSpecify, $exprType, $nativeType),
 			],
 		);
 	}
@@ -1814,7 +1806,6 @@ private function revertNonNullability(MutatingScope $scope, array $specifiedExpr
 				$specifiedExpressionResult->getExpression(),
 				$specifiedExpressionResult->getOriginalType(),
 				$specifiedExpressionResult->getOriginalNativeType(),
-				$specifiedExpressionResult->getCertainty(),
 			);
 		}
 
diff --git a/src/Analyser/TypeSpecifier.php b/src/Analyser/TypeSpecifier.php
index 1280e3fedc..0a5fbb8511 100644
--- a/src/Analyser/TypeSpecifier.php
+++ b/src/Analyser/TypeSpecifier.php
@@ -717,14 +717,11 @@ public function specifyTypesInCondition(
 
 			$types = null;
 			foreach ($vars as $var) {
-				$type = new SpecifiedTypes();
-
 				if ($var instanceof Expr\Variable && is_string($var->name)) {
 					if ($scope->hasVariableType($var->name)->no()) {
 						return new SpecifiedTypes([], [], false, [], $rootExpr);
 					}
 				}
-
 				if (
 					$var instanceof ArrayDimFetch
 					&& $var->dim !== null
@@ -741,32 +738,36 @@ public function specifyTypesInCondition(
 							$scope,
 							$rootExpr,
 						);
+					} else {
+						$type = new SpecifiedTypes();
 					}
+
+					$type = $type->unionWith(
+						$this->create($var, new NullType(), TypeSpecifierContext::createFalse(), false, $scope, $rootExpr),
+					);
+				} else {
+					$type = $this->create($var, new NullType(), TypeSpecifierContext::createFalse(), false, $scope, $rootExpr);
 				}
 
 				if (
 					$var instanceof PropertyFetch
 					&& $var->name instanceof Node\Identifier
 				) {
-					$type = $this->create($var->var, new IntersectionType([
+					$type = $type->unionWith($this->create($var->var, new IntersectionType([
 						new ObjectWithoutClassType(),
 						new HasPropertyType($var->name->toString()),
-					]), TypeSpecifierContext::createTruthy(), false, $scope, $rootExpr);
+					]), TypeSpecifierContext::createTruthy(), false, $scope, $rootExpr));
 				} elseif (
 					$var instanceof StaticPropertyFetch
 					&& $var->class instanceof Expr
 					&& $var->name instanceof Node\VarLikeIdentifier
 				) {
-					$type = $this->create($var->class, new IntersectionType([
+					$type = $type->unionWith($this->create($var->class, new IntersectionType([
 						new ObjectWithoutClassType(),
 						new HasPropertyType($var->name->toString()),
-					]), TypeSpecifierContext::createTruthy(), false, $scope, $rootExpr);
+					]), TypeSpecifierContext::createTruthy(), false, $scope, $rootExpr));
 				}
 
-				$type = $type->unionWith(
-					$this->create($var, new NullType(), TypeSpecifierContext::createFalse(), false, $scope, $rootExpr),
-				);
-
 				if ($types === null) {
 					$types = $type;
 				} else {
@@ -791,15 +792,6 @@ public function specifyTypesInCondition(
 		} elseif (
 			$expr instanceof Expr\Empty_
 		) {
-			if (!$scope instanceof MutatingScope) {
-				throw new ShouldNotHappenException();
-			}
-
-			$isset = $scope->issetCheck($expr->expr, static fn () => true);
-			if ($isset === false) {
-				return new SpecifiedTypes();
-			}
-
 			return $this->specifyTypesInCondition($scope, new BooleanOr(
 				new Expr\BooleanNot(new Expr\Isset_([$expr->expr])),
 				new Expr\BooleanNot($expr->expr),
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
index ac945e2ed3..d77d7e435c 100644
--- a/tests/PHPStan/Analyser/NodeScopeResolverTest.php
+++ b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -1362,9 +1362,6 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/impure-connection-fns.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-9963.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-9995.php');
-		yield from $this->gatherAssertTypes(__DIR__ . '/data/falsey-isset-certainty.php');
-		yield from $this->gatherAssertTypes(__DIR__ . '/data/falsey-empty-certainty.php');
-		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-7291.php');
 	}
 
 	/**
diff --git a/tests/PHPStan/Analyser/data/bug-7291.php b/tests/PHPStan/Analyser/data/bug-7291.php
deleted file mode 100644
index cae3e945b3..0000000000
--- a/tests/PHPStan/Analyser/data/bug-7291.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php declare(strict_types=1);
-
-namespace Bug7291;
-
-use PHPStan\TrinaryLogic;
-use function PHPStan\Testing\assertType;
-use function PHPStan\Testing\assertVariableCertainty;
-
-class HelloWorld
-{
-	public function doFoo(): void
-	{
-		if (rand(0, 1)) {
-			$a = rand(0, 1) ? new \stdClass() : null;
-		}
-
-		assertType('stdClass|null', $a);
-		assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-
-		echo $a?->foo;
-
-		assertType('stdClass|null', $a);
-		assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	}
-}
diff --git a/tests/PHPStan/Analyser/data/falsey-empty-certainty.php b/tests/PHPStan/Analyser/data/falsey-empty-certainty.php
deleted file mode 100644
index cde86585aa..0000000000
--- a/tests/PHPStan/Analyser/data/falsey-empty-certainty.php
+++ /dev/null
@@ -1,69 +0,0 @@
-<?php
-
-namespace FalseyEmptyCertainty;
-
-use function PHPStan\Testing\assertVariableCertainty;
-use PHPStan\TrinaryLogic;
-
-function falseyEmptyArrayDimFetch(): void
-{
-	if (rand() % 2) {
-		$a = ['bar' => null];
-		if (rand() % 3) {
-			$a = ['bar' => 'hello'];
-		}
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	if (empty($a['bar'])) {
-		assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	} else {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-}
-
-function falseyEmptyUncertainPropertyFetch(): void
-{
-	if (rand() % 2) {
-		$a = new \stdClass();
-		if (rand() % 3) {
-			$a->x = 'hello';
-		}
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	if (empty($a->x)) {
-		assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	} else {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-}
-
-function justEmpty(): void
-{
-	assertVariableCertainty(TrinaryLogic::createNo(), $foo);
-	if (!empty($foo)) {
-		assertVariableCertainty(TrinaryLogic::createNo(), $foo);
-	} else {
-		assertVariableCertainty(TrinaryLogic::createNo(), $foo);
-	}
-	assertVariableCertainty(TrinaryLogic::createNo(), $foo);
-}
-
-function maybeEmpty(): void
-{
-	if (rand() % 2) {
-		$foo = 1;
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $foo);
-	if (!empty($foo)) {
-		assertVariableCertainty(TrinaryLogic::createYes(), $foo);
-	} else {
-		assertVariableCertainty(TrinaryLogic::createMaybe(), $foo);
-	}
-}
diff --git a/tests/PHPStan/Analyser/data/falsey-isset-certainty.php b/tests/PHPStan/Analyser/data/falsey-isset-certainty.php
deleted file mode 100644
index f13f702364..0000000000
--- a/tests/PHPStan/Analyser/data/falsey-isset-certainty.php
+++ /dev/null
@@ -1,168 +0,0 @@
-<?php
-
-namespace FalseyIssetCertainty;
-
-use function PHPStan\Testing\assertType;
-use function PHPStan\Testing\assertVariableCertainty;
-use PHPStan\TrinaryLogic;
-
-
-function falseyIssetArrayDimFetchOnProperty(): void
-{
-	$a = new \stdClass();
-	$a->bar = null;
-	if (rand() % 3) {
-		$a->bar = 'hello';
-	}
-
-	assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	if (isset($a->bar)) {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	} else {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	}
-
-	assertVariableCertainty(TrinaryLogic::createYes(), $a);
-}
-
-function falseyIssetUncertainArrayDimFetchOnProperty(): void
-{
-	if (rand() % 2) {
-		$a = new \stdClass();
-		$a->bar = null;
-		$a = ['bar' => null];
-		if (rand() % 3) {
-			$a->bar = 'hello';
-		}
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	if (isset($a->bar)) {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	} else {
-		assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-}
-
-function falseyIssetUncertainPropertyFetch(): void
-{
-	if (rand() % 2) {
-		$a = new \stdClass();
-		if (rand() % 3) {
-			$a->x = 'hello';
-		}
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	if (isset($a->x)) {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	} else {
-		assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-}
-
-function falseyIssetArrayDimFetch(): void
-{
-	$a = ['bar' => null];
-	if (rand() % 3) {
-		$a = ['bar' => 'hello'];
-	}
-
-	assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	if (isset($a['bar'])) {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	} else {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	}
-
-	assertVariableCertainty(TrinaryLogic::createYes(), $a);
-}
-
-function falseyIssetUncertainArrayDimFetch(): void
-{
-	if (rand() % 2) {
-		$a = ['bar' => null];
-		if (rand() % 3) {
-			$a = ['bar' => 'hello'];
-		}
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	if (isset($a['bar'])) {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	} else {
-		assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-}
-
-function falseyIssetVariable(): void
-{
-	if (rand() % 2) {
-		$a = 'bar';
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	if (isset($a)) {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-	} else {
-		assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-	}
-
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $a);
-}
-
-function falseyIssetWithAssignment(): void
-{
-	if (rand() % 2) {
-		$x = ['x' => 1];
-	}
-
-	if (isset($x[$z = getFoo()])) {
-		assertVariableCertainty(TrinaryLogic::createYes(), $z);
-		assertVariableCertainty(TrinaryLogic::createYes(), $x);
-
-	} else {
-		assertVariableCertainty(TrinaryLogic::createYes(), $z);
-		assertVariableCertainty(TrinaryLogic::createMaybe(), $x);
-	}
-
-	assertVariableCertainty(TrinaryLogic::createYes(), $z);
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $x);
-}
-
-function justIsset(): void
-{
-	if (isset($foo)) {
-		assertVariableCertainty(TrinaryLogic::createNo(), $foo);
-	}
-}
-
-function maybeIsset(): void
-{
-	if (rand() % 2) {
-		$foo = 1;
-	}
-	assertVariableCertainty(TrinaryLogic::createMaybe(), $foo);
-	if (isset($foo)) {
-		assertVariableCertainty(TrinaryLogic::createYes(), $foo);
-		assertType('1', $foo);
-	}
-}
-
-function isStringNarrowsMaybeCertainty(int $i, string $s): void
-{
-	if (rand(0, 1)) {
-		$a = rand(0,1) ? $i : $s;
-	}
-
-	if (is_string($a)) {
-		assertVariableCertainty(TrinaryLogic::createYes(), $a);
-		echo $a;
-	}
-}
diff --git a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
index 0bae922d49..8e4e9a3033 100644
--- a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
+++ b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
@@ -102,10 +102,6 @@ public function testDefinedVariables(): void
 				'Undefined variable: $variableInEmpty',
 				145,
 			],
-			[
-				'Undefined variable: $negatedVariableInEmpty',
-				152,
-			],
 			[
 				'Undefined variable: $variableInEmpty',
 				155,
@@ -997,24 +993,6 @@ public function testBug5326(): void
 		$this->analyse([__DIR__ . '/data/bug-5326.php'], []);
 	}
 
-	public function testIsStringNarrowsCertainty(): void
-	{
-		$this->cliArgumentsVariablesRegistered = true;
-		$this->polluteScopeWithLoopInitialAssignments = true;
-		$this->checkMaybeUndefinedVariables = true;
-		$this->polluteScopeWithAlwaysIterableForeach = true;
-		$this->analyse([__DIR__ . '/data/isstring-certainty.php'], [
-			[
-				'Variable $a might not be defined.',
-				11,
-			],
-			[
-				'Undefined variable: $a',
-				19,
-			],
-		]);
-	}
-
 	public function testBug5266(): void
 	{
 		$this->cliArgumentsVariablesRegistered = true;
diff --git a/tests/PHPStan/Rules/Variables/IssetRuleTest.php b/tests/PHPStan/Rules/Variables/IssetRuleTest.php
index 34caffcc7b..a9c594bec5 100644
--- a/tests/PHPStan/Rules/Variables/IssetRuleTest.php
+++ b/tests/PHPStan/Rules/Variables/IssetRuleTest.php
@@ -450,21 +450,4 @@ public function testObjectShapes(): void
 		$this->analyse([__DIR__ . '/data/isset-object-shapes.php'], []);
 	}
 
-	public function testBug3985(): void
-	{
-		$this->treatPhpDocTypesAsCertain = true;
-		$this->strictUnnecessaryNullsafePropertyFetch = true;
-
-		$this->analyse([__DIR__ . '/../../Analyser/data/bug-3985.php'], [
-			[
-				'Variable $foo in isset() is never defined.',
-				13,
-			],
-			[
-				'Variable $foo in isset() is never defined.',
-				21,
-			],
-		]);
-	}
-
 }
diff --git a/tests/PHPStan/Rules/Variables/data/isstring-certainty.php b/tests/PHPStan/Rules/Variables/data/isstring-certainty.php
deleted file mode 100644
index 270e978e68..0000000000
--- a/tests/PHPStan/Rules/Variables/data/isstring-certainty.php
+++ /dev/null
@@ -1,22 +0,0 @@
-<?php
-
-namespace IsStringCertainty;
-
-function maybeDefinedVariable(int $i, string $s): void
-{
-	if (rand(0, 1)) {
-		$a = rand(0,1) ? $i : $s;
-	}
-
-	if (is_string($a)) {
-		echo $a; // we don't want an error here
-	}
-}
-
-
-function isStringNoCertainty(): void
-{
-	if (is_string($a)) {
-		echo $a; // we don't want an error here
-	}
-}