diff --git a/src/org/jetbrains/java/decompiler/code/cfg/ControlFlowGraph.java b/src/org/jetbrains/java/decompiler/code/cfg/ControlFlowGraph.java
index 3c6b14d..08223cf 100644
--- a/src/org/jetbrains/java/decompiler/code/cfg/ControlFlowGraph.java
+++ b/src/org/jetbrains/java/decompiler/code/cfg/ControlFlowGraph.java
@@ -745,7 +745,7 @@ public class ControlFlowGraph implements CodeConstants {
     return res;
   }
 
-  private static void addToReversePostOrderListIterative(BasicBlock root, List<BasicBlock> lst) {
+  private static void addToReversePostOrderListIterative(BasicBlock root, List<? super BasicBlock> lst) {
 
     LinkedList<BasicBlock> stackNode = new LinkedList<>();
     LinkedList<Integer> stackIndex = new LinkedList<>();
diff --git a/src/org/jetbrains/java/decompiler/main/ClassReference14Processor.java b/src/org/jetbrains/java/decompiler/main/ClassReference14Processor.java
index a6369f5..41b5a9a 100644
--- a/src/org/jetbrains/java/decompiler/main/ClassReference14Processor.java
+++ b/src/org/jetbrains/java/decompiler/main/ClassReference14Processor.java
@@ -74,7 +74,7 @@ public class ClassReference14Processor {
     }
   }
 
-  private static void processClassRec(ClassNode node, Map<ClassWrapper, MethodWrapper> mapClassMeths, Set<ClassWrapper> setFound) {
+  private static void processClassRec(ClassNode node, Map<ClassWrapper, MethodWrapper> mapClassMeths, Set<? super ClassWrapper> setFound) {
     ClassWrapper wrapper = node.getWrapper();
 
     // search code
diff --git a/src/org/jetbrains/java/decompiler/main/decompiler/ConsoleDecompiler.java b/src/org/jetbrains/java/decompiler/main/decompiler/ConsoleDecompiler.java
index 684249e..120470d 100644
--- a/src/org/jetbrains/java/decompiler/main/decompiler/ConsoleDecompiler.java
+++ b/src/org/jetbrains/java/decompiler/main/decompiler/ConsoleDecompiler.java
@@ -83,7 +83,7 @@ public class ConsoleDecompiler implements IBytecodeProvider, IResultSaver {
   }
 
   @SuppressWarnings("UseOfSystemOutOrSystemErr")
-  private static void addPath(List<File> list, String path) {
+  private static void addPath(List<? super File> list, String path) {
     File file = new File(path);
     if (file.exists()) {
       list.add(file);
diff --git a/src/org/jetbrains/java/decompiler/main/rels/NestedClassProcessor.java b/src/org/jetbrains/java/decompiler/main/rels/NestedClassProcessor.java
index 1b91f44..da17532 100644
--- a/src/org/jetbrains/java/decompiler/main/rels/NestedClassProcessor.java
+++ b/src/org/jetbrains/java/decompiler/main/rels/NestedClassProcessor.java
@@ -798,7 +798,7 @@ public class NestedClassProcessor {
     return null;
   }
 
-  private static Statement getDefStatement(Statement stat, VarType classType, Set<Statement> setStats) {
+  private static Statement getDefStatement(Statement stat, VarType classType, Set<? super Statement> setStats) {
     List<Exprent> lst = new ArrayList<>();
     Statement retStat = null;
 
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/StackVarsProcessor.java b/src/org/jetbrains/java/decompiler/modules/decompiler/StackVarsProcessor.java
index c235387..1232e64 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/StackVarsProcessor.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/StackVarsProcessor.java
@@ -525,7 +525,7 @@ public class StackVarsProcessor {
     return new Object[]{null, changed, false};
   }
 
-  private static boolean getUsedVersions(SSAUConstructorSparseEx ssa, VarVersionPair var, List<VarVersionNode> res) {
+  private static boolean getUsedVersions(SSAUConstructorSparseEx ssa, VarVersionPair var, List<? super VarVersionNode> res) {
     VarVersionsGraph ssuversions = ssa.getSsuversions();
     VarVersionNode varnode = ssuversions.nodes.getWithKey(var);
 
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/sforms/DirectGraph.java b/src/org/jetbrains/java/decompiler/modules/decompiler/sforms/DirectGraph.java
index 6f33885..aa2fae8 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/sforms/DirectGraph.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/sforms/DirectGraph.java
@@ -39,7 +39,7 @@ public class DirectGraph {
     }
   }
 
-  private static void addToReversePostOrderListIterative(DirectNode root, List<DirectNode> lst) {
+  private static void addToReversePostOrderListIterative(DirectNode root, List<? super DirectNode> lst) {
 
     LinkedList<DirectNode> stackNode = new LinkedList<>();
     LinkedList<Integer> stackIndex = new LinkedList<>();
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/stats/Statement.java b/src/org/jetbrains/java/decompiler/modules/decompiler/stats/Statement.java
index e57e9ef..b5e8213 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/stats/Statement.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/stats/Statement.java
@@ -546,7 +546,7 @@ public class Statement implements IMatchable {
   // private methods
   // *****************************************************************************
 
-  private static void addToReversePostOrderListIterative(Statement root, List<Statement> lst) {
+  private static void addToReversePostOrderListIterative(Statement root, List<? super Statement> lst) {
 
     LinkedList<Statement> stackNode = new LinkedList<>();
     LinkedList<Integer> stackIndex = new LinkedList<>();
@@ -589,7 +589,7 @@ public class Statement implements IMatchable {
   }
 
 
-  private static void addToPostReversePostOrderList(Statement stat, List<Statement> lst, HashSet<Statement> setVisited) {
+  private static void addToPostReversePostOrderList(Statement stat, List<? super Statement> lst, HashSet<? super Statement> setVisited) {
 
     if (setVisited.contains(stat)) { // because of not considered exception edges, s. isExitComponent. Should be rewritten, if possible.
       return;
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionsGraph.java b/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionsGraph.java
index e295915..58eda68 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionsGraph.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionsGraph.java
@@ -99,7 +99,7 @@ public class VarVersionsGraph {
     return lst;
   }
 
-  private static void addToReversePostOrderListIterative(VarVersionNode root, List<VarVersionNode> lst, Set<VarVersionNode> setVisited) {
+  private static void addToReversePostOrderListIterative(VarVersionNode root, List<? super VarVersionNode> lst, Set<? super VarVersionNode> setVisited) {
     Map<VarVersionNode, List<VarVersionEdge>> mapNodeSuccs = new HashMap<>();
     LinkedList<VarVersionNode> stackNode = new LinkedList<>();
     LinkedList<Integer> stackIndex = new LinkedList<>();
diff --git a/src/org/jetbrains/java/decompiler/struct/gen/generics/GenericMain.java b/src/org/jetbrains/java/decompiler/struct/gen/generics/GenericMain.java
index 45ca557..3e4e1f1 100644
--- a/src/org/jetbrains/java/decompiler/struct/gen/generics/GenericMain.java
+++ b/src/org/jetbrains/java/decompiler/struct/gen/generics/GenericMain.java
@@ -95,7 +95,7 @@ public class GenericMain {
     }
   }
 
-  private static String parseFormalParameters(String signature, List<String> parameters, List<List<GenericType>> bounds) {
+  private static String parseFormalParameters(String signature, List<? super String> parameters, List<? super List<GenericType>> bounds) {
     if (signature.charAt(0) != '<') {
       return signature;
     }