From 2e5a6537773d740db22b707fe196da0f5dc2d942 Mon Sep 17 00:00:00 2001
From: Anna Kozlova <anna.kozlova@jetbrains.com>
Date: Tue, 19 Jan 2016 16:31:41 +0100
Subject: [PATCH] inference: reuse dependencies graph

---
 .../resolve/graphInference/InferenceSession.java   | 14 ++++++--------
 .../graphInference/InferenceVariablesOrder.java    |  7 +++++--
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
index 4dfe008219e6..4ced9fde48ed 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
@@ -570,9 +570,9 @@ public class InferenceSession {
   }
   
   PsiSubstitutor prepareSubstitution() {
-    ArrayList<InferenceVariable> allVars = new ArrayList<InferenceVariable>(myInferenceVariables);
-    while (!allVars.isEmpty()) {
-      final List<InferenceVariable> variables = InferenceVariablesOrder.resolveOrder(allVars, this);
+    Iterator<List<InferenceVariable>> iterator = InferenceVariablesOrder.resolveOrderIterator(myInferenceVariables, this);
+    while (iterator.hasNext()) {
+      final List<InferenceVariable> variables = iterator.next();
       for (InferenceVariable inferenceVariable : variables) {
         final PsiTypeParameter typeParameter = inferenceVariable.getParameter();
         PsiType instantiation = inferenceVariable.getInstantiation();
@@ -583,7 +583,6 @@ public class InferenceSession {
             .put(typeParameter, JavaPsiFacade.getInstance(typeParameter.getProject()).getElementFactory().createType(typeParameter));
         }
       }
-      allVars.removeAll(variables);
     }
     return mySiteSubstitutor;
   }
@@ -1053,11 +1052,10 @@ public class InferenceSession {
 
   private PsiSubstitutor resolveSubsetOrdered(Set<InferenceVariable> varsToResolve, PsiSubstitutor siteSubstitutor) {
     PsiSubstitutor substitutor = siteSubstitutor;
-    final HashSet<InferenceVariable> copy = new HashSet<InferenceVariable>(varsToResolve);
-    while (!copy.isEmpty()) {
-      final List<InferenceVariable> vars = InferenceVariablesOrder.resolveOrder(copy, this);
+    final Iterator<List<InferenceVariable>> varsIterator = InferenceVariablesOrder.resolveOrderIterator(varsToResolve, this);
+    while (varsIterator.hasNext()) {
+      List<InferenceVariable> vars = varsIterator.next();
       final PsiSubstitutor resolveSubset = resolveSubset(vars, substitutor);
-      copy.removeAll(vars);
       substitutor = substitutor.putAll(resolveSubset);
     }
     return substitutor;
diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceVariablesOrder.java b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceVariablesOrder.java
index 1c91b060b6a8..65bcac7e6e80 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceVariablesOrder.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceVariablesOrder.java
@@ -27,8 +27,11 @@ import java.util.*;
  */
 
 public class InferenceVariablesOrder {
-
   public static List<InferenceVariable> resolveOrder(Collection<InferenceVariable> vars, InferenceSession session) {
+    return resolveOrderIterator(vars, session).next();
+  }
+  
+  public static Iterator<List<InferenceVariable>> resolveOrderIterator(Collection<InferenceVariable> vars, InferenceSession session) {
     Map<InferenceVariable, InferenceGraphNode<InferenceVariable>> nodes =
       new LinkedHashMap<InferenceVariable, InferenceGraphNode<InferenceVariable>>();
     for (InferenceVariable var : vars) {
@@ -52,7 +55,7 @@ public class InferenceVariablesOrder {
       public List<InferenceVariable> fun(InferenceGraphNode<InferenceVariable> node) {
         return node.getValue();
       }
-    }).iterator().next();
+    }).iterator();
   }
 
   public static <T> List<List<InferenceGraphNode<T>>> tarjan(Collection<InferenceGraphNode<T>> nodes) {