diff --git a/src/Rules/FunctionCallParametersCheck.php b/src/Rules/FunctionCallParametersCheck.php
index 6e40e86408..0e339e9981 100644
--- a/src/Rules/FunctionCallParametersCheck.php
+++ b/src/Rules/FunctionCallParametersCheck.php
@@ -27,6 +27,7 @@
 use function array_fill;
 use function array_key_exists;
 use function count;
+use function implode;
 use function is_string;
 use function max;
 use function sprintf;
@@ -278,7 +279,6 @@ public function check(
 
 			if ($this->checkArgumentTypes) {
 				$parameterType = TypeUtils::resolveLateResolvableTypes($parameter->getType());
-				$parameterDescription = sprintf('%s$%s', $parameter->isVariadic() ? '...' : '', $parameter->getName());
 
 				if (
 					!$parameter->passedByReference()->createsNewVariable()
@@ -290,11 +290,7 @@ public function check(
 						$verbosityLevel = VerbosityLevel::getRecommendedLevelByType($parameterType, $argumentValueType);
 						$errors[] = RuleErrorBuilder::message(sprintf(
 							$messages[6],
-							$argumentName === null ? sprintf(
-								'#%d %s',
-								$i + 1,
-								$parameterDescription,
-							) : $parameterDescription,
+							$this->describeParameter($parameter, $argumentName === null ? $i + 1 : null),
 							$parameterType->describe($verbosityLevel),
 							$argumentValueType->describe($verbosityLevel),
 						))
@@ -313,11 +309,7 @@ public function check(
 				) {
 					$errors[] = RuleErrorBuilder::message(sprintf(
 						$messages[13],
-						$argumentName === null ? sprintf(
-							'#%d %s',
-							$i + 1,
-							$parameterDescription,
-						) : $parameterDescription,
+						$this->describeParameter($parameter, $argumentName === null ? $i + 1 : null),
 					))->identifier('argument.unresolvableType')->line($argumentLine)->build();
 				}
 
@@ -329,11 +321,7 @@ public function check(
 				) {
 					$errors[] = RuleErrorBuilder::message(sprintf(
 						$messages[6],
-						$argumentName === null ? sprintf(
-							'#%d %s',
-							$i + 1,
-							$parameterDescription,
-						) : $parameterDescription,
+						$this->describeParameter($parameter, $argumentName === null ? $i + 1 : null),
 						'bindable closure',
 						'static closure',
 					))
@@ -351,10 +339,9 @@ public function check(
 			}
 
 			if ($this->nullsafeCheck->containsNullSafe($argumentValue)) {
-				$parameterDescription = sprintf('%s$%s', $parameter->isVariadic() ? '...' : '', $parameter->getName());
 				$errors[] = RuleErrorBuilder::message(sprintf(
 					$messages[8],
-					$argumentName === null ? sprintf('#%d %s', $i + 1, $parameterDescription) : $parameterDescription,
+					$this->describeParameter($parameter, $argumentName === null ? $i + 1 : null),
 				))
 					->identifier('argument.byRef')
 					->line($argumentLine)
@@ -381,10 +368,9 @@ public function check(
 						$propertyDescription = sprintf('readonly property %s::$%s', $propertyReflection->getDeclaringClass()->getDisplayName(), $propertyReflection->getName());
 					}
 
-					$parameterDescription = sprintf('%s$%s', $parameter->isVariadic() ? '...' : '', $parameter->getName());
 					$errors[] = RuleErrorBuilder::message(sprintf(
 						'Parameter %s is passed by reference so it does not accept %s.',
-						$argumentName === null ? sprintf('#%d %s', $i + 1, $parameterDescription) : $parameterDescription,
+						$this->describeParameter($parameter, $argumentName === null ? $i + 1 : null),
 						$propertyDescription,
 					))->identifier('argument.byRef')->line($argumentLine)->build();
 				}
@@ -397,10 +383,9 @@ public function check(
 				continue;
 			}
 
-			$parameterDescription = sprintf('%s$%s', $parameter->isVariadic() ? '...' : '', $parameter->getName());
 			$errors[] = RuleErrorBuilder::message(sprintf(
 				$messages[8],
-				$argumentName === null ? sprintf('#%d %s', $i + 1, $parameterDescription) : $parameterDescription,
+				$this->describeParameter($parameter, $argumentName === null ? $i + 1 : null),
 			))->identifier('argument.byRef')->line($argumentLine)->build();
 		}
 
@@ -600,4 +585,19 @@ private function processArguments(
 		return [$errors, $newArguments];
 	}
 
+	private function describeParameter(ParameterReflection $parameter, ?int $position): string
+	{
+		$parts = [];
+		if ($position !== null) {
+			$parts[] = '#' . $position;
+		}
+
+		$name = $parameter->getName();
+		if ($name !== '') {
+			$parts[] = ($parameter->isVariadic() ? '...$' : '$') . $name;
+		}
+
+		return implode(' ', $parts);
+	}
+
 }
diff --git a/tests/PHPStan/Levels/data/callableVariance-5.json b/tests/PHPStan/Levels/data/callableVariance-5.json
index 81682ac6e7..c37c7adeb0 100644
--- a/tests/PHPStan/Levels/data/callableVariance-5.json
+++ b/tests/PHPStan/Levels/data/callableVariance-5.json
@@ -1,6 +1,6 @@
 [
     {
-        "message": "Parameter #1 $ of callable callable(Levels\\CallableVariance\\B): void expects Levels\\CallableVariance\\B, Levels\\CallableVariance\\A given.",
+        "message": "Parameter #1 of callable callable(Levels\\CallableVariance\\B): void expects Levels\\CallableVariance\\B, Levels\\CallableVariance\\A given.",
         "line": 14,
         "ignorable": true
     },
@@ -39,4 +39,4 @@
         "line": 85,
         "ignorable": true
     }
-]
\ No newline at end of file
+]
diff --git a/tests/PHPStan/Rules/Functions/CallCallablesRuleTest.php b/tests/PHPStan/Rules/Functions/CallCallablesRuleTest.php
index bc20e208da..bcd1c9ee87 100644
--- a/tests/PHPStan/Rules/Functions/CallCallablesRuleTest.php
+++ b/tests/PHPStan/Rules/Functions/CallCallablesRuleTest.php
@@ -190,7 +190,7 @@ public function dataBug3566(): array
 				true,
 				[
 					[
-						'Parameter #1 $ of closure expects int, TMemberType given.',
+						'Parameter #1 of closure expects int, TMemberType given.',
 						29,
 					],
 				],
@@ -280,7 +280,7 @@ public function testBug6485(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-6485.php'], [
 			[
-				'Parameter #1 $ of closure expects never, TBlockType of Bug6485\Block given.',
+				'Parameter #1 of closure expects never, TBlockType of Bug6485\Block given.',
 				33,
 			],
 		]);
@@ -306,4 +306,14 @@ public function testBug9614(): void
 		$this->analyse([__DIR__ . '/data/bug-9614.php'], []);
 	}
 
+	public function testBug10814(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-10814.php'], [
+			[
+				'Parameter #1 of closure expects DateTime, DateTimeImmutable given.',
+				10,
+			],
+		]);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Functions/data/bug-10814.php b/tests/PHPStan/Rules/Functions/data/bug-10814.php
new file mode 100644
index 0000000000..a1c7ed8cbe
--- /dev/null
+++ b/tests/PHPStan/Rules/Functions/data/bug-10814.php
@@ -0,0 +1,12 @@
+<?php declare(strict_types = 1);
+
+namespace Bug10814;
+
+class HelloWorld
+{
+	/** @param \Closure(\DateTime): void $fx */
+	public function foo($fx): void
+	{
+		$fx(new \DateTimeImmutable());
+	}
+}