IDEA-112567 Don't show any completion variants after method reference and dot

java/java-impl/src/com/intellij/codeInsight/completion/JavaCompletionContributor.java

@@ -35,6 +35,7 @@ import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.patterns.ElementPattern;
 import com.intellij.patterns.PatternCondition;
+import com.intellij.patterns.PsiJavaElementPattern;
 import com.intellij.patterns.PsiNameValuePairPattern;
 import com.intellij.pom.java.LanguageLevel;
 import com.intellij.psi.*;
@@ -78,6 +79,8 @@ public class JavaCompletionContributor extends CompletionContributor {
 
   public static final ElementPattern<PsiElement> ANNOTATION_NAME = psiElement().
     withParents(PsiJavaCodeReferenceElement.class, PsiAnnotation.class).afterLeaf("@");
+  private static final PsiJavaElementPattern.Capture<PsiElement> UNEXPECTED_REFERENCE_AFTER_DOT =
+    psiElement().afterLeaf(".").insideStarting(psiExpressionStatement());
 
   private static JavaCompletionData getCompletionData(LanguageLevel level) {
     final Set<Map.Entry<LanguageLevel, JavaCompletionData>> entries = ourCompletionData.entrySet();
@@ -203,7 +206,7 @@ public class JavaCompletionContributor extends CompletionContributor {
       return;
     }
 
-    if (AFTER_NUMBER_LITERAL.accepts(position)) {
+    if (AFTER_NUMBER_LITERAL.accepts(position) || UNEXPECTED_REFERENCE_AFTER_DOT.accepts(position)) {
       _result.stopHere();
       return;
     }

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/Normal8CompletionTest.groovy

@@ -50,4 +50,13 @@ class Foo {{ Object o = Fo<caret>x }}
 class Foo {{ Object o = Foo::<caret>x }}
 """
   }
+
+  public void testNoSuggestionsAfterMethodReferenceAndDot() {
+    String text = """
+class Foo {{ Object o = StringBuilder::append.<caret> }}
+"""
+    myFixture.configureByText "a.java", text
+    assertEmpty(myFixture.completeBasic())
+    myFixture.checkResult(text)
+  }
 }