StreamToLoopInspection fixed when collection result is non-trivial generic type involving ? extends wildcards

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterCollectExtends2.java

@@ -0,0 +1,26 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class Main {
+  private List<? extends CharSequence> asList(CharSequence s) {
+    return Collections.singletonList(s);
+  }
+
+  public List<? extends CharSequence> getList() {
+    return Collections.emptyList();
+  }
+
+  private void collect() {
+      List<List<? extends CharSequence>> list = new ArrayList<>();
+      for (CharSequence charSequence : getList()) {
+          List<? extends CharSequence> charSequences = asList(charSequence);
+          list.add(charSequences);
+      }
+      List<? extends List<? extends CharSequence>> res2 = list;
+    System.out.println(res2);
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterCollectExtendsGroupingBy.java

@@ -0,0 +1,25 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class Main {
+  static class MyList<T, X> extends ArrayList<X> {}
+
+  public List<CharSequence> getList() {
+    return Collections.emptyList();
+  }
+
+  public MyList<? extends Number, CharSequence> createList() {
+    return new MyList<>();
+  }
+
+  private void collect() {
+      Map<Integer, MyList<? extends Number, CharSequence>> result = new HashMap<>();
+      for (CharSequence x : getList()) {
+          result.computeIfAbsent(x.length(), k -> createList()).add(x);
+      }
+      Map<Integer, ? extends MyList<? extends Number, ? extends CharSequence>> map =
+              result;
+    System.out.println(map);
+  }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterCollectExtendsMyList.java

@@ -0,0 +1,29 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class Main {
+  static class MyList<T> extends ArrayList<List<? extends CharSequence>> {
+  }
+
+  private List<? extends CharSequence> asList(CharSequence s) {
+    return Collections.singletonList(s);
+  }
+
+  public List<? extends CharSequence> getList() {
+    return Collections.emptyList();
+  }
+
+  private void collect() {
+      MyList<? extends List<? extends CharSequence>> res2 =
+              new MyList<>();
+      for (CharSequence charSequence : getList()) {
+          List<? extends CharSequence> charSequences = asList(charSequence);
+          res2.add(charSequences);
+      }
+      System.out.println(res2);
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterCollectExtendsToMap.java

@@ -0,0 +1,28 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.*;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class Main {
+  public List<? extends CharSequence> asList(CharSequence s) {
+    return Collections.singletonList(s);
+  }
+
+  public List<? extends CharSequence> getList() {
+    return Collections.emptyList();
+  }
+
+  private void collect() {
+      Map<CharSequence, List<? extends CharSequence>> result = new HashMap<>();
+      for (CharSequence charSequence : getList()) {
+          if (Objects.nonNull(charSequence)) {
+              if (result.put(charSequence, asList(charSequence)) != null) {
+                  throw new IllegalStateException("Duplicate key");
+              }
+          }
+      }
+      Map<? extends CharSequence, ? extends List<? extends CharSequence>> map = result;
+    System.out.println(map);
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeCollectExtends2.java

@@ -0,0 +1,21 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class Main {
+  private List<? extends CharSequence> asList(CharSequence s) {
+    return Collections.singletonList(s);
+  }
+
+  public List<? extends CharSequence> getList() {
+    return Collections.emptyList();
+  }
+
+  private void collect() {
+    List<? extends List<? extends CharSequence>> res2 = getList().stream().map(this::asList).col<caret>lect(Collectors.toList());
+    System.out.println(res2);
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeCollectExtendsGroupingBy.java

@@ -0,0 +1,24 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class Main {
+  static class MyList<T, X> extends ArrayList<X> {}
+
+  public List<CharSequence> getList() {
+    return Collections.emptyList();
+  }
+
+  public MyList<? extends Number, CharSequence> createList() {
+    return new MyList<>();
+  }
+
+  private void collect() {
+    Map<Integer, ? extends MyList<? extends Number, ? extends CharSequence>> map =
+      getList().stream().co<caret>llect(Collectors.groupingBy(x -> x.length(), Collectors.toCollection(this::createList)));
+    System.out.println(map);
+  }

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeCollectExtendsMyList.java

@@ -0,0 +1,25 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class Main {
+  static class MyList<T> extends ArrayList<List<? extends CharSequence>> {
+  }
+
+  private List<? extends CharSequence> asList(CharSequence s) {
+    return Collections.singletonList(s);
+  }
+
+  public List<? extends CharSequence> getList() {
+    return Collections.emptyList();
+  }
+
+  private void collect() {
+    MyList<? extends List<? extends CharSequence>> res2 =
+      getList().stream().map(this::asList).coll<caret>ect(Collectors.toCollection(MyList::new));
+    System.out.println(res2);
+  }
+}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/beforeCollectExtendsToMap.java

@@ -0,0 +1,21 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.*;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class Main {
+  public List<? extends CharSequence> asList(CharSequence s) {
+    return Collections.singletonList(s);
+  }
+
+  public List<? extends CharSequence> getList() {
+    return Collections.emptyList();
+  }
+
+  private void collect() {
+    Map<? extends CharSequence, ? extends List<? extends CharSequence>> map = getList()
+      .stream().filter(Objects::nonNull).co<caret>llect(Collectors.toMap(Function.identity(), this::asList));
+    System.out.println(map);
+  }
+}