[groovy] treat void argument as null (IDEA-206425)

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/resolve/processors/inference/inference.kt

@@ -19,6 +19,7 @@ import org.jetbrains.plugins.groovy.lang.resolve.api.ExpressionArgument
 import org.jetbrains.plugins.groovy.lang.resolve.api.JustTypeArgument
 import org.jetbrains.plugins.groovy.lang.resolve.api.UnknownArgument
 import org.jetbrains.plugins.groovy.lang.resolve.processors.ClassHint
+import org.jetbrains.plugins.groovy.lang.typing.devoid
 
 fun getTopLevelType(expression: GrExpression): PsiType? {
   if (expression is GrMethodCall) {
@@ -27,7 +28,7 @@ fun getTopLevelType(expression: GrExpression): PsiType? {
       val session = GroovyInferenceSessionBuilder(expression, it, resolved.contextSubstitutor)
         .resolveMode(false)
         .build()
-      return session.inferSubst().substitute(PsiUtil.getSmartReturnType(it.method))
+      return session.inferSubst().substitute(PsiUtil.getSmartReturnType(it.method).devoid(expression))
     }
     return null
   }

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/typing/DefaultMethodCallTypeCalculator.kt

@@ -1,4 +1,4 @@
-// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.plugins.groovy.lang.typing
 
 import com.intellij.openapi.extensions.ExtensionPointName
@@ -70,7 +70,7 @@ private fun getTypeFromPropertyCall(element: PsiElement?, expression: GrMethodCa
   return GrClosureSignatureUtil.getReturnType(type.signatures, argumentTypes, expression)
 }
 
-private fun PsiType?.devoid(context: PsiElement): PsiType? {
+fun PsiType?.devoid(context: PsiElement): PsiType? {
   return if (this == PsiType.VOID && !PsiUtil.isCompileStatic(context)) PsiType.NULL else this
 }
 

plugins/groovy/test/org/jetbrains/plugins/groovy/lang/resolve/ResolveMethod2Test.groovy

@@ -0,0 +1,20 @@
+// Copyright 2000-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package org.jetbrains.plugins.groovy.lang.resolve
+
+import groovy.transform.CompileStatic
+import org.jetbrains.plugins.groovy.lang.psi.api.GroovyMethodResult
+import org.jetbrains.plugins.groovy.lang.resolve.api.Applicability
+import org.jetbrains.plugins.groovy.util.GroovyLatestTest
+import org.jetbrains.plugins.groovy.util.ResolveTest
+import org.junit.Test
+
+@CompileStatic
+class ResolveMethod2Test extends GroovyLatestTest implements ResolveTest {
+
+  @Test
+  void 'void argument'() {
+    def result = advancedResolveByText 'def foo(p); void bar(); <caret>foo(bar())'
+    assert result instanceof GroovyMethodResult
+    assert ((GroovyMethodResult)result).applicability == Applicability.applicable
+  }
+}