Java: better error message on duplicate reference in extends/implements list (IDEA-354856)

GitOrigin-RevId: 0ba4eed5966c273f94552d7fe623a69bb6eb6c95

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

@@ -734,29 +734,27 @@ public final class HighlightClassUtil {
     return null;
   }
 
-  static HighlightInfo.Builder checkExtendsDuplicate(@NotNull PsiJavaCodeReferenceElement element, @Nullable PsiElement resolved, @NotNull PsiFile containingFile) {
+  static HighlightInfo.Builder checkExtendsDuplicate(@NotNull PsiJavaCodeReferenceElement element, 
+                                                     @Nullable PsiElement resolved, 
+                                                     @NotNull PsiFile containingFile) {
     if (!(element.getParent() instanceof PsiReferenceList list)) return null;
     if (!(list.getParent() instanceof PsiClass)) return null;
     if (!(resolved instanceof PsiClass aClass)) return null;
-    PsiClassType[] referencedTypes = list.getReferencedTypes();
-    int dupCount = 0;
     PsiManager manager = containingFile.getManager();
-    for (PsiClassType referencedType : referencedTypes) {
-      PsiClass resolvedElement = referencedType.resolve();
-      if (resolvedElement != null && manager.areElementsEquivalent(resolvedElement, aClass)) {
-        dupCount++;
-      }
+    PsiJavaCodeReferenceElement sibling = PsiTreeUtil.getPrevSiblingOfType(element, PsiJavaCodeReferenceElement.class);
+    while (true) {
+      if (sibling == null) return null;
+      PsiElement target = sibling.resolve();
+      if (manager.areElementsEquivalent(target, aClass)) break;
+      sibling = PsiTreeUtil.getPrevSiblingOfType(sibling, PsiJavaCodeReferenceElement.class);
     }
-    if (dupCount > 1) {
-      String name = HighlightUtil.formatClass(aClass);
-      String description = JavaErrorBundle.message("duplicate.class", name);
-      HighlightInfo.Builder info =
-        HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(element).descriptionAndTooltip(description);
-      IntentionAction action = QuickFixFactory.getInstance().createRemoveDuplicateExtendsAction(name);
-      info.registerFix(action, null, null, null, null);
-      return info;
-    }
-    return null;
+    String name = HighlightUtil.formatClass(aClass);
+    String description = JavaErrorBundle.message("duplicate.reference.in.list", name, list.getFirstChild().getText());
+    HighlightInfo.Builder info =
+      HighlightInfo.newHighlightInfo(HighlightInfoType.ERROR).range(element).descriptionAndTooltip(description);
+    IntentionAction action = QuickFixFactory.getInstance().createRemoveDuplicateExtendsAction(name);
+    info.registerFix(action, null, null, null, null);
+    return info;
   }
 
   static HighlightInfo.Builder checkClassAlreadyImported(@NotNull PsiClass aClass, @NotNull PsiElement elementToHighlight) {

java/java-psi-impl/resources/messages/JavaErrorBundle.properties

@@ -112,6 +112,7 @@ class.must.implement.method=Class ''{0}'' must implement abstract method ''{1}''
 abstract.cannot.be.instantiated=''{0}'' is abstract; cannot be instantiated
 duplicate.class.in.other.file=Duplicate class found in the file ''{0}''
 duplicate.class=Duplicate class: ''{0}''
+duplicate.reference.in.list=Duplicate reference to ''{0}'' in ''{1}'' list
 public.class.should.be.named.after.file=Class ''{0}'' is public, should be declared in a file named ''{0}.java''
 inheritance.from.final.class=Cannot inherit from {1} ''{0}''
 package.name.file.path.mismatch=Package name ''{0}'' does not correspond to the file path ''{1}''

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting/DuplicateClass.java

@@ -3,10 +3,10 @@
 class a {
 }
 
-class b extends <error descr="Duplicate class: 'a'">a</error>, <error descr="Duplicate class: 'a'">a</error> {
+class b extends a, <error descr="Duplicate reference to 'a' in 'extends' list">a</error> {
 }
 
 interface i {}
 
-class c implements <error descr="Duplicate class: 'i'">i</error>, <error descr="Duplicate class: 'i'">i</error> {
+class c implements i, <error descr="Duplicate reference to 'i' in 'implements' list">i</error> {
 }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlightingPatternsInSwitch/BrokenSealedHierarchy.java

@@ -19,7 +19,7 @@ final class A1 extends Sealed1 {
 final class C1 extends Sealed1 {
 }
 
-sealed abstract class Sealed2 permits <error descr="Duplicate class: 'A2'">A2</error>, <error descr="Duplicate class: 'A2'">A2</error> {
+sealed abstract class Sealed2 permits A2, <error descr="Duplicate reference to 'A2' in 'permits' list">A2</error> {
 }
 
 final class A2 extends Sealed2 {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlightingSealedTypes/PermitsList.java

@@ -4,7 +4,7 @@ import java.lang.annotation.Target;
 
 interface I0 <error descr="Invalid permits clause: 'I0' must be sealed">permits</error> I {}
 
-sealed interface I extends I0 permits <error descr="Cannot resolve symbol 'Unresolved'">Unresolved</error>, <error descr="Duplicate class: 'p.I1'">I1</error>, <error descr="Duplicate class: 'p.I1'">I1</error>{}
+sealed interface I extends I0 permits <error descr="Cannot resolve symbol 'Unresolved'">Unresolved</error>, I1, <error descr="Duplicate reference to 'p.I1' in 'permits' list">I1</error>{}
 non-sealed interface I1 extends I {}
 
 sealed interface <error descr="Sealed class permits clause must contain all subclasses">A</error> {}