method references: don't swallow errors during method ref inference (IDEA-179706)

java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java

@@ -15,6 +15,7 @@
  */
 package com.intellij.psi.impl.source.resolve.graphInference;
 
+import com.intellij.codeInsight.PsiEquivalenceUtil;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.util.Comparing;
 import com.intellij.openapi.util.Key;
@@ -1640,6 +1641,11 @@ public class InferenceSession {
         }
       }
 
+      //no additional constraints for array creation
+      if (PsiEquivalenceUtil.areElementsEquivalent(containingClass, JavaPsiFacade.getElementFactory(reference.getProject()).getArrayClass(PsiUtil.getLanguageLevel(reference)))) {
+        return null;
+      }
+
       final PsiType qType = JavaPsiFacade.getElementFactory(method.getProject()).createType(containingClass, psiSubstitutor);
 
       addConstraint(new TypeCompatibilityConstraint(substituteWithInferenceVariables(qType), pType));

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

@@ -17,6 +17,7 @@ package com.intellij.psi.impl.source.tree.java;
 
 import com.intellij.codeInsight.PsiEquivalenceUtil;
 import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.*;
 import com.intellij.psi.impl.source.resolve.ParameterTypeInferencePolicy;
 import com.intellij.psi.impl.source.resolve.ResolveCache;
@@ -124,6 +125,10 @@ public class MethodReferenceResolver implements ResolveCache.PolyVariantContextR
                   }
 
                   if (!session.repeatInferencePhases()) {
+                    List<String> errorMessages = session.getIncompatibleErrorMessages();
+                    if (errorMessages != null) {
+                      setApplicabilityError(StringUtil.join(errorMessages, "\n"));
+                    }
                     return substitutor;
                   }
 
@@ -140,6 +145,7 @@ public class MethodReferenceResolver implements ResolveCache.PolyVariantContextR
                 @Override
                 public boolean isApplicable() {
                   if (signature == null) return false;
+                  if (getInferenceErrorMessageAssumeAlreadyComputed() != null) return false;
                   final PsiType[] argTypes = signature.getParameterTypes();
                   boolean hasReceiver = PsiMethodReferenceUtil.isSecondSearchPossible(argTypes, qualifierResolveResult, reference);
 

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/methodRef/AccessModifiers.java

@@ -24,7 +24,7 @@ class AlienTest {
 
     static {
         IInt i1 = MyTest::<error descr="Cannot resolve method 'abracadabra'">abracadabra</error>;
-        IInt i2 = MyTest::<error descr="Cannot resolve method 'foo'">foo</error>;
+        IInt i2 = MyTest::<error descr="Incompatible types: int is not convertible to String">foo</error>;
         IInt i3 = MyTest::<error descr="Cannot resolve method 'bar'">bar</error>;
         <error descr="Incompatible types. Found: '<method reference>', required: 'AlienTest.IIntInt'">IIntInt i4 = MyTest::bar;</error>
         IInt i5 = <error descr="Non-static method cannot be referenced from a static context">MyTest::baz</error>;

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/methodRef/Ambiguity.java

@@ -47,7 +47,7 @@ class MyTest1 {
     }
 
     {
-        Bar1 b1 = MyTest2 :: <error descr="Cannot resolve method 'foo'">foo</error>;
+        Bar1 b1 = MyTest2 :: <error descr="Incompatible types: String is not convertible to int">foo</error>;
         bar(MyTest1 :: foo);
     }
 }
@@ -73,7 +73,7 @@ class MyTest2 {
     }*/
 
     {
-        Bar1 b1 = MyTest2 :: <error descr="Cannot resolve method 'foo'">foo</error>;
+        Bar1 b1 = MyTest2 :: <error descr="Incompatible types: String is not convertible to int">foo</error>;
         bar(MyTest2 :: foo);
     }
 }
@@ -99,8 +99,8 @@ class MyTest3 {
     }
 
     {
-        Bar1 b1 = MyTest2 :: <error descr="Cannot resolve method 'foo'">foo</error>;
+        Bar1 b1 = MyTest2 :: <error descr="Incompatible types: String is not convertible to int">foo</error>;
-        bar(MyTest3 :: <error descr="Cannot resolve method 'foo'">foo</error>);
+        bar(MyTest3 :: <error descr="Incompatible types: int is not convertible to String">foo</error>);
     }
 }
 

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/methodRef/Assignability.java

@@ -2,7 +2,7 @@ class Test {
   {
       Runnable b = Test :: <error descr="Cannot resolve method 'length'">length</error>;
       Comparable<String> c = Test :: length;
-      Comparable<Integer> c1 =  Test :: <error descr="Cannot resolve method 'length'">length</error>;
+      Comparable<Integer> c1 =  Test :: <error descr="Incompatible types: Integer is not convertible to String">length</error>;
   }
 
   public static Integer length(String s) {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/methodRef/Varargs.java

@@ -49,7 +49,7 @@ class MyTest {
     static {
         I1 i1 = MyTest::static_1;
         I1 i2 = MyTest::<error descr="Cannot resolve method 'static_2'">static_2</error>;
-        I1 i3 = MyTest::<error descr="Cannot resolve method 'static_3'">static_3</error>;
+        I1 i3 = MyTest::<error descr="Incompatible types: int is not convertible to String">static_3</error>;
         I1 i4 = MyTest::<error descr="Cannot resolve method 'static_4'">static_4</error>;
     }
 
@@ -62,7 +62,7 @@ class MyTest {
 
         I1 i1 = this::_1;
         I1 i2 = this::<error descr="Cannot resolve method '_2'">_2</error>;
-        I1 i3 = this::<error descr="Cannot resolve method '_3'">_3</error>;
+        I1 i3 = this::<error descr="Incompatible types: int is not convertible to String">_3</error>;
         I1 i4 = this::<error descr="Cannot resolve method '_4'">_4</error>;
 
         I2 i21 = MyTest::<error descr="Cannot resolve method 'm1'">m1</error>;

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/ApplicabilityConflictMessage.java

@@ -5,7 +5,7 @@ class A {
   public static void main(String[] args) {
     B<? extends CharSequence> q = new B<>();
 
-    Func x = q::<error descr="Cannot resolve method 'foo'">foo</error>;
+    Func x = q::<error descr="Incompatible types: CharSequence is not convertible to capture of ? extends CharSequence">foo</error>;
     x.invoke("");
   }
 

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/CapturedTypesOfImplicitParameterTypes.java

@@ -7,7 +7,7 @@ interface B<BT> {
 
 class Test {
   public static void test() {
-    method1(Test::<error descr="Cannot resolve method 'method2'">method2</error>);
+    method1(Test::<error descr="Incompatible types: A<capture of ? super M> is not convertible to A<? super String>">method2</error>);
   }
 
   static <M> void method1(B<A<? super M>> arg) { }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/DistinguishCapturedWildcardsByDifferentParameters.java

@@ -4,7 +4,7 @@ import java.util.function.Predicate;
 
 class MyTest {
   {
-    BiConsumer<Predicate<? extends Runnable>, Predicate<? extends Runnable>> or = MyTest::<error descr="Cannot resolve method 'or'">or</error>;
+    BiConsumer<Predicate<? extends Runnable>, Predicate<? extends Runnable>> or = MyTest::<error descr="Incompatible equality constraint: capture of ? extends Runnable and capture of ? extends Runnable">or</error>;
   }
 
   private static <E extends Runnable> void or(Predicate<E> left, Predicate<E> right) {}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/HighlightReferenceWhenContradictBoundsAreInferred.java

@@ -29,14 +29,14 @@ class Test {
     static void meth4(I3 s) { }
 
     static {
-        meth1(Foo::<error descr="Cannot resolve constructor 'Foo'">new</error>);
+        meth1(Foo::<error descr="no instance(s) of type variable(s)  exist so that String conforms to Number">new</error>);
         meth2(Foo::new);
-        meth3(Foo::<error descr="Cannot resolve constructor 'Foo'">new</error>);
+        meth3(Foo::<error descr="no instance(s) of type variable(s)  exist so that Object conforms to Number">new</error>);
         meth4<error descr="Ambiguous method call: both 'Test.meth4(I1)' and 'Test.meth4(I2)' match">(Foo::new)</error>;
 
-        meth1(Test::<error descr="Cannot resolve method 'foo'">foo</error>);
+        meth1(Test::<error descr="no instance(s) of type variable(s)  exist so that String conforms to Number">foo</error>);
         meth2(Test::foo);
-        meth3(Test::<error descr="Cannot resolve method 'foo'">foo</error>);
+        meth3(Test::<error descr="no instance(s) of type variable(s)  exist so that Object conforms to Number">foo</error>);
         meth4<error descr="Ambiguous method call: both 'Test.meth4(I1)' and 'Test.meth4(I2)' match">(Test::foo)</error>;
     }
 
@@ -55,8 +55,8 @@ class Test {
     }
 
     void test() {
-      II1 i1 = this::<error descr="Cannot resolve method 'fooInstance'">fooInstance</error>;
+      II1 i1 = this::<error descr="no instance(s) of type variable(s)  exist so that X conforms to Number">fooInstance</error>;
       II2 i2 = this::fooInstance;
-      II3 i3 = this::<error descr="Cannot resolve method 'fooInstance'">fooInstance</error>;
+      II3 i3 = this::<error descr="no instance(s) of type variable(s)  exist so that X conforms to Number">fooInstance</error>;
     }
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/MethodReferenceSwallowedErrors.java

@@ -0,0 +1,45 @@
+
+import java.util.function.Supplier;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+interface Regression<S, T, A, B> {
+  <F extends Functor, FT extends Functor<T, F>, FB extends Functor<B, F>> FT apply(
+    Function<? super A, ? extends FB> fn, S s);
+
+  static <S, T, A, B> Regression<S, T, A, B> regression(Function<? super S, ? extends A> getter,
+                                                        BiFunction<? super S, ? super B, ? extends T> setter) {
+    return new Regression<S, T, A, B>() {
+      @Override
+      @SuppressWarnings("unchecked")
+      public <F extends Functor, FT extends Functor<T, F>, FB extends Functor<B, F>> FT apply(
+        Function<? super A, ? extends FB> fn,
+        S s) {
+        return null; //doesn't matter
+      }
+    };
+  }
+
+  @SuppressWarnings("unchecked")
+  static <S, A> Simple<S, A> simple(Function<? super S, ? extends A> getter,
+                                    BiFunction<? super S, ? super A, ? extends S> setter) {
+    return regression(getter, setter)::<error descr="Incompatible equality constraint: capture of ? super A and B">apply</error>; // java9 fails to compile this line
+  }
+
+  interface Functor<X, F extends Functor> {
+  }
+
+  @FunctionalInterface
+  interface Simple<S, A> extends Regression<S, S, A, A> {
+  }
+}
+
+interface SimplifiedTest<B> {
+  <FB extends Functor<B>> FB apply(Supplier<? extends FB> fn);
+
+  static <A> SimplifiedTest<A> simple(final SimplifiedTest<? super A> regression) {
+    return regression::<error descr="no instance(s) of type variable(s)  exist so that capture of ? extends FB conforms to Functor<capture of ? super A>">apply</error>;
+  }
+
+  interface Functor<X> { }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/NonExactMethodReferenceOnRawClassType.java

@@ -4,7 +4,7 @@ class InlineRef {
   <K> void foo(Consumer<K> f) {}
 
   void bar(){
-    foo(Descriptor::<error descr="Cannot resolve method 'getName'">getName</error>);
+    foo(Descriptor::<error descr="Incompatible types: Object is not convertible to Descriptor">getName</error>);
   }
 }
 

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

@@ -177,6 +177,7 @@ public class NewMethodRefHighlightingTest extends LightDaemonAnalyzerTestCase {
   public void testConstructorRefOnClassWithRecursiveTypeParameter() { doTest(); }
   public void testWildcardInCheckedCompatibilityConstraints() { doTest(); }
   public void testConstructorReferenceWithVarargsParameters() { doTest(); }
+  public void testMethodReferenceSwallowedErrors() { doTest(); }
 
   public void testPreferErrorOnTopLevelToFailedSubstitutorOnNestedLevel() { doTest(); }