[java-inspections] IDEA-326718 skip not reassigned variables

GitOrigin-RevId: acdfa3cd6fd701f6a61ca0a461d179b1bda107c7

java/java-impl-inspections/src/com/intellij/codeInspection/defUse/DefUseInspection.java

@@ -111,11 +111,15 @@ public class DefUseInspection extends AbstractBaseJavaLocalInspectionTool {
                  context instanceof PsiPostfixExpression && REPORT_POSTFIX_EXPRESSIONS) {
           holder.registerProblem(context, JavaBundle.message("inspection.unused.assignment.problem.descriptor4"));
         }
-        else if (REPORT_PATTERN_VARIABLE && psiVariable instanceof PsiPatternVariable) {
+        else if (REPORT_PATTERN_VARIABLE && psiVariable instanceof PsiPatternVariable &&
+                 //case is covered with `Java | Declaration redundancy | Unused declaration`
+                 info.isWriteOutsideDeclaration()) {
           holder.registerProblem(psiVariable.getNameIdentifier(), JavaBundle.message("inspection.unused.assignment.problem.descriptor5"));
         }
         else if (REPORT_FOR_EACH_PARAMETER && context instanceof PsiForeachStatement foreachStatement &&
-                  foreachStatement.getIterationParameter() == psiVariable && psiVariable.getNameIdentifier() != null) {
+                  foreachStatement.getIterationParameter() == psiVariable && psiVariable.getNameIdentifier() != null &&
+                 //case is covered with `Java | Declaration redundancy | Unused declaration`
+                 info.isWriteOutsideDeclaration()) {
           holder.registerProblem(psiVariable.getNameIdentifier(), JavaBundle.message("inspection.unused.assignment.problem.descriptor6"));
         }
       }

java/java-psi-impl/src/com/intellij/psi/controlFlow/DefUseUtil.java

@@ -31,10 +31,13 @@ public final class DefUseUtil {
     private final PsiElement myContext;
     private final boolean myIsRead;
 
-    public Info(@NotNull PsiVariable variable, @NotNull PsiElement context, boolean read) {
+    private final boolean myWriteOutsideDeclaration;
+
+    public Info(@NotNull PsiVariable variable, @NotNull PsiElement context, boolean read, boolean writeOutsideDeclaration) {
       myVariable = variable;
       myContext = context;
       myIsRead = read;
+      myWriteOutsideDeclaration = writeOutsideDeclaration;
     }
 
     @NotNull
@@ -50,6 +53,9 @@ public final class DefUseUtil {
     public boolean isRead() {
       return myIsRead;
     }
+    public boolean isWriteOutsideDeclaration() {
+      return myWriteOutsideDeclaration;
+    }
   }
 
   private static class InstructionState implements Comparable<InstructionState> {
@@ -143,6 +149,7 @@ public final class DefUseUtil {
     }
 
     Set<PsiVariable> assignedVariables = new HashSet<>();
+    Set<PsiVariable> assignedSeveralTimes = new HashSet<>();
     Set<PsiVariable> readVariables = new HashSet<>();
     for (int i = 0; i < instructions.size(); i++) {
       Instruction instruction = instructions.get(i);
@@ -153,7 +160,9 @@ public final class DefUseUtil {
         context = PsiTreeUtil.getParentOfType(context, PsiStatement.class, false);
         PsiVariable psiVariable = writeInstruction.variable;
         if (context != null && !(context instanceof PsiDeclarationStatement && psiVariable.getInitializer() == null)) {
-          assignedVariables.add(psiVariable);
+          if (!assignedVariables.add(psiVariable)) {
+            assignedSeveralTimes.add(psiVariable);
+          }
         }
       }
       else if (instruction instanceof ReadVariableInstruction) {
@@ -241,11 +250,11 @@ public final class DefUseUtil {
           if (context != null) {
             if (context instanceof PsiDeclarationStatement && psiVariable.getInitializer() == null) {
               if (!assignedVariables.contains(psiVariable)) {
-                unusedDefs.add(new Info(psiVariable, context, false));
+                unusedDefs.add(new Info(psiVariable, context, false, assignedSeveralTimes.contains(psiVariable)));
               }
             }
             else {
-              unusedDefs.add(new Info(psiVariable, context, readVariables.contains(psiVariable)));
+              unusedDefs.add(new Info(psiVariable, context, readVariables.contains(psiVariable), assignedSeveralTimes.contains(psiVariable)));
             }
           }
         }

java/java-tests/testData/inspection/defUse/ForEachIterationParameter.java

@@ -4,6 +4,8 @@ class Test {
       arg = "test";
       System.out.println(arg);
     }
+    for (String ignored : args) {
+    }
 
     for (String arg : args) {
       if (args.length == 1) {

java/java-tests/testData/inspection/defUse/PatternVariable.java

@@ -4,6 +4,8 @@ class Test {
       s = "hello"; // not reported
       System.out.println(s);
     }
+    if (object instanceof String ignored) {
+    }
 
     if (object instanceof R(var x, var <warning descr="The value of pattern variable 'y' is never used">y</warning>)) {
       if (1 == 1) {