diff --git a/src/main/java/org/assertj/vavr/api/AbstractValidationAssert.java b/src/main/java/org/assertj/vavr/api/AbstractValidationAssert.java
index 4ebcc1e..64916f8 100644
--- a/src/main/java/org/assertj/vavr/api/AbstractValidationAssert.java
+++ b/src/main/java/org/assertj/vavr/api/AbstractValidationAssert.java
@@ -111,6 +111,7 @@ public SELF containsInvalid(INVALID expectedErrorValue) {
      */
     public SELF containsValidSame(VALID expectedValue) {
         assertIsValid();
+        checkNotNull(expectedValue);
         if (actual.get() != expectedValue)
             throwAssertionError(shouldContainValidSame(actual, expectedValue));
         return myself;
@@ -122,7 +123,7 @@ public SELF containsValidSame(VALID expectedValue) {
      * @param expectedErrorValue the expected value inside the {@link io.vavr.control.Validation}.
      * @return this assertion object.
      */
-    public SELF containsInvalidSame(VALID expectedErrorValue) {
+    public SELF containsInvalidSame(INVALID expectedErrorValue) {
         assertIsInvalid();
         checkNotNull(expectedErrorValue);
         if (actual.getError() != expectedErrorValue)
diff --git a/src/main/java/org/assertj/vavr/api/ValidationShouldContain.java b/src/main/java/org/assertj/vavr/api/ValidationShouldContain.java
index b98bc22..4b2d17a 100644
--- a/src/main/java/org/assertj/vavr/api/ValidationShouldContain.java
+++ b/src/main/java/org/assertj/vavr/api/ValidationShouldContain.java
@@ -94,7 +94,7 @@ static <INVALID, VALID> ValidationShouldContain shouldContainValidSame(Validatio
      * @param <VALID>            type of the value in the case of the valid {@link Validation}.
      * @return an error message factory
      */
-    static <INVALID, VALID> ValidationShouldContain shouldContainInvalidSame(Validation<INVALID, VALID> validation, VALID expectedErrorValue) {
+    static <INVALID, VALID> ValidationShouldContain shouldContainInvalidSame(Validation<INVALID, VALID> validation, INVALID expectedErrorValue) {
         return validation.isInvalid() ?
                 new ValidationShouldContain(EXPECTING_TO_CONTAIN_SAME, validation, expectedErrorValue) :
                 shouldContainButIsValid(validation, expectedErrorValue);
diff --git a/src/test/java/org/assertj/vavr/api/ValidationAssert_containsValidSame_Test.java b/src/test/java/org/assertj/vavr/api/ValidationAssert_containsValidSame_Test.java
index 8a0b552..a46eac9 100644
--- a/src/test/java/org/assertj/vavr/api/ValidationAssert_containsValidSame_Test.java
+++ b/src/test/java/org/assertj/vavr/api/ValidationAssert_containsValidSame_Test.java
@@ -35,6 +35,15 @@ void should_fail_when_validation_is_null() {
                 .hasMessage(actualIsNull());
     }
 
+    @Test
+    void should_fail_if_expected_value_is_null() {
+        assertThatThrownBy(
+                () -> assertThat(Validation.valid("something")).containsValidSame(null)
+        )
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("The expected value should not be <null>.");
+    }
+
     @Test
     void should_pass_if_validation_contains_same_instance_as_valid_value() {
         final String value = "something";