graph inference: take into account present type args during graph inference (IDEA-103023)

(cherry picked from commit e9e05d9d47210f6e315cef233f8b5b33192df7fc)

java/java-psi-api/src/com/intellij/psi/infos/MethodCandidateInfo.java

@@ -151,6 +151,23 @@ public class MethodCandidateInfo extends CandidateInfo{
                                       : PsiExpression.EMPTY_ARRAY);
   }
 
+  public PsiSubstitutor inferSubstitutorFromArgs(final ParameterTypeInferencePolicy policy, final PsiExpression[] arguments) {
+    if (myTypeArguments == null) {
+      return inferTypeArguments(policy, arguments);
+    }
+    else {
+      PsiSubstitutor incompleteSubstitutor = super.getSubstitutor();
+      PsiMethod method = getElement();
+      if (method != null) {
+        PsiTypeParameter[] typeParams = method.getTypeParameters();
+        for (int i = 0; i < myTypeArguments.length && i < typeParams.length; i++) {
+          incompleteSubstitutor = incompleteSubstitutor.put(typeParams[i], myTypeArguments[i]);
+        }
+      }
+      return incompleteSubstitutor;
+    }
+  }
+  
   public PsiSubstitutor inferTypeArguments(final ParameterTypeInferencePolicy policy, final PsiExpression[] arguments) {
     Map<PsiElement, Pair<PsiMethod, PsiSubstitutor>> map = CURRENT_CANDIDATE.get();
     if (map == null) {

java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/ProcessCandidateParameterTypeInferencePolicy.java

@@ -71,7 +71,7 @@ public class ProcessCandidateParameterTypeInferencePolicy extends DefaultParamet
   protected PsiSubstitutor getSubstitutor(PsiCallExpression contextCall, PsiExpression[] expressions, int i, JavaResolveResult result) {
     if (result instanceof MethodCandidateInfo) {
       List<PsiExpression> leftArgs = getExpressions(expressions, i);
-      return ((MethodCandidateInfo)result).inferTypeArguments(this, leftArgs.toArray(new PsiExpression[leftArgs.size()]));
+      return ((MethodCandidateInfo)result).inferSubstitutorFromArgs(this, leftArgs.toArray(new PsiExpression[leftArgs.size()]));
     }
     else {
       return result.getSubstitutor();

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/graphInference/InferFromTypeArgs.java

@@ -0,0 +1,10 @@
+import java.util.*;
+public class DiamondTest {
+
+    public <U> void foo(ArrayList<U> p) {}
+
+    public void test() {
+        DiamondTest diamondTest = new DiamondTest();
+        diamondTest.<Integer>foo(new ArrayList<>(3));
+    }
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/GraphInferenceHighlightingTest.java

@@ -76,6 +76,10 @@ public class GraphInferenceHighlightingTest extends LightDaemonAnalyzerTestCase
     doTest();
   }
 
+  public void testInferFromTypeArgs() throws Exception {
+    doTest();
+  }
+
   private void doTest() throws Exception {
     doTest(false);
   }