lvti: forbid var/explicit type mix

don't treat var as explicit type

java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/HighlightVisitorImpl.java

@@ -331,6 +331,8 @@ public class HighlightVisitorImpl extends JavaElementVisitor implements Highligh
                      .descriptionAndTooltip("Lambda expression not expected here").create());
     }
 
+    if (!myHolder.hasErrorResults()) myHolder.add(LambdaHighlightingUtil.checkConsistentParameterDeclaration(expression));
+    
     PsiType functionalInterfaceType = null;
     if (!myHolder.hasErrorResults()) {
       functionalInterfaceType = expression.getFunctionalInterfaceType();

java/java-analysis-impl/src/com/intellij/codeInsight/daemon/impl/analysis/LambdaHighlightingUtil.java

@@ -116,4 +116,25 @@ public class LambdaHighlightingUtil {
     }
     return functionalInterfaceType.getPresentableText() + " is not a functional interface";
   }
+
+  public static HighlightInfo checkConsistentParameterDeclaration(PsiLambdaExpression expression) {
+    PsiParameter[] parameters = expression.getParameterList().getParameters();
+    if (parameters.length < 2) return null;
+    boolean hasExplicitParameterTypes = hasExplicitType(parameters[0]);
+    for (int i = 1; i < parameters.length; i++) {
+      if (hasExplicitParameterTypes != hasExplicitType(parameters[i])) {
+        return HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR)
+                            .descriptionAndTooltip("Cannot mix 'var' and explicitly typed parameters in lambda expression")
+                            .range(expression.getParameterList())
+                            .create();
+      }
+    }
+
+    return null;
+  }
+
+  private static boolean hasExplicitType(PsiParameter parameter) {
+    PsiTypeElement typeElement = parameter.getTypeElement();
+    return typeElement != null && !typeElement.isInferredType();
+  }
 }

java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiLambdaExpressionImpl.java

@@ -159,7 +159,9 @@ public class PsiLambdaExpressionImpl extends JavaStubPsiElement<FunctionalExpres
   public boolean hasFormalParameterTypes() {
     final PsiParameter[] parameters = getParameterList().getParameters();
     for (PsiParameter parameter : parameters) {
-      if (parameter.getTypeElement() == null) return false;
+      PsiTypeElement typeElement = parameter.getTypeElement();
+      if (typeElement == null) return false;
+      if (typeElement.isInferredType()) return false;
     }
     return true;
   }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting11/MixedVarAndExplicitTypesInLambdaDeclaration.java

@@ -0,0 +1,10 @@
+interface I {
+  void m(int i, int j);
+}
+
+class Main {
+  void foo() {
+    I in = <error descr="Cannot mix 'var' and explicitly typed parameters in lambda expression">(var i, int j)</error> -> {};
+    I in1 = (var i, <error descr="Cannot resolve symbol 'j'">j</error><error descr="Identifier expected">)</error> -> {};
+  }
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/daemon/LightAdvHighlightingJdk11Test.java

@@ -21,6 +21,14 @@ public class LightAdvHighlightingJdk11Test extends LightDaemonAnalyzerTestCase {
     IdeaTestUtil.setTestVersion(JavaSdkVersion.JDK_10, getModule(), getTestRootDisposable());//todo
   }
 
+  private void doTest() {
+    doTest(BASE_PATH + "/" + getTestName(false) + ".java", false, false);
+  }
+
+  public void testMixedVarAndExplicitTypesInLambdaDeclaration() {
+    doTest();
+  }
+
   public void testGotoDeclarationOnLambdaVarParameter() {
     configureByFile(BASE_PATH + "/" + getTestName(false) + ".java");
     final int offset = getEditor().getCaretModel().getOffset();