diff --git a/java/java-psi-api/src/com/intellij/psi/PsiTypeParameterList.java b/java/java-psi-api/src/com/intellij/psi/PsiTypeParameterList.java
index 706b78a6de62..146b4226cf0d 100644
--- a/java/java-psi-api/src/com/intellij/psi/PsiTypeParameterList.java
+++ b/java/java-psi-api/src/com/intellij/psi/PsiTypeParameterList.java
@@ -34,5 +34,5 @@ public interface PsiTypeParameterList extends PsiElement {
    * @param typeParameter the parameter to find.
    * @return the index of the parameter.
    */
-  int getTypeParameterIndex (PsiTypeParameter typeParameter);
+  int getTypeParameterIndex(@NotNull PsiTypeParameter typeParameter);
 }
diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsTypeParametersListImpl.java b/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsTypeParametersListImpl.java
index 1961a1e4f108..7c41efda2920 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsTypeParametersListImpl.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsTypeParametersListImpl.java
@@ -50,7 +50,7 @@ public class ClsTypeParametersListImpl extends ClsRepositoryPsiElement<PsiTypePa
   }
 
   @Override
-  public int getTypeParameterIndex(PsiTypeParameter typeParameter) {
+  public int getTypeParameterIndex(@NotNull PsiTypeParameter typeParameter) {
     assert typeParameter.getParent() == this;
     return PsiImplUtil.getTypeParameterIndex(typeParameter, this);
   }
diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/light/LightTypeParameterListBuilder.java b/java/java-psi-impl/src/com/intellij/psi/impl/light/LightTypeParameterListBuilder.java
index 083ad2631cb3..d2fab82cb7ab 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/light/LightTypeParameterListBuilder.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/light/LightTypeParameterListBuilder.java
@@ -62,7 +62,7 @@ public class LightTypeParameterListBuilder extends LightElement implements PsiTy
   }
 
   @Override
-  public int getTypeParameterIndex(PsiTypeParameter typeParameter) {
+  public int getTypeParameterIndex(@NotNull PsiTypeParameter typeParameter) {
     return myParameters.indexOf(typeParameter);
   }
 
diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiTypeParameterListImpl.java b/java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiTypeParameterListImpl.java
index b83e7507060f..affc847872ac 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiTypeParameterListImpl.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiTypeParameterListImpl.java
@@ -42,7 +42,7 @@ public class PsiTypeParameterListImpl extends JavaStubPsiElement<PsiTypeParamete
   }
 
   @Override
-  public int getTypeParameterIndex(PsiTypeParameter typeParameter) {
+  public int getTypeParameterIndex(@NotNull PsiTypeParameter typeParameter) {
     LOG.assertTrue(typeParameter.getParent() == this);
     return PsiImplUtil.getTypeParameterIndex(typeParameter, this);
   }
diff --git a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/synthetic/GrLightTypeParameterList.java b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/synthetic/GrLightTypeParameterList.java
index 9f7cdd81c25a..0e5f501691c7 100644
--- a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/synthetic/GrLightTypeParameterList.java
+++ b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/synthetic/GrLightTypeParameterList.java
@@ -32,7 +32,7 @@ public class GrLightTypeParameterList extends LightElement implements GrTypePara
   }
 
   @Override
-  public int getTypeParameterIndex(PsiTypeParameter typeParameter) {
+  public int getTypeParameterIndex(@NotNull PsiTypeParameter typeParameter) {
     //noinspection SuspiciousMethodCalls
     return myTypeParameters.indexOf(typeParameter);
   }
diff --git a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/types/GrTypeParameterListImpl.java b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/types/GrTypeParameterListImpl.java
index 8fd9628cc18b..419d73f1a671 100644
--- a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/types/GrTypeParameterListImpl.java
+++ b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/types/GrTypeParameterListImpl.java
@@ -45,7 +45,7 @@ public class GrTypeParameterListImpl extends GrStubElementBase<EmptyStub>
   }
 
   @Override
-  public int getTypeParameterIndex(PsiTypeParameter typeParameter) {
+  public int getTypeParameterIndex(@NotNull PsiTypeParameter typeParameter) {
     final GrTypeParameter[] typeParameters = getTypeParameters();
     for (int i = 0; i < typeParameters.length; i++) {
       if (typeParameters[i].equals(typeParameter)) return i;