MethodReturnTypeFix: updated fix to change method return type based on return statements in method body (IDEA-216275)

GitOrigin-RevId: e97990950039123c8c41921a71342b8ed60afdee
2026-09-18 09:34:34 +07:00 · 2019-07-04 09:02:24 +03:00
parent 52aa1ae553
commit 42d733a694
42 changed files with 381 additions and 55 deletions
@@ -1,6 +1,6 @@
 class C {
-  <error descr="Illegal type: 'void'">void</error>[] m1() { }
-  <error descr="Illegal type: 'void'">void</error> m2()[] { }
+  <error descr="Illegal type: 'void'">void</error>[] <error descr="Invalid return type">m1</error>() { }
+  <error descr="Illegal type: 'void'">void</error> <error descr="Invalid return type">m2</error>()[] { }
  void m3(<error descr="Illegal type: 'void'">void</error> p) {}

  {
@@ -6,7 +6,7 @@ interface ii {}



- int f1() throws Exception {
+ int <error descr="Invalid return type">f1</error>() throws Exception {
 <error descr="Missing return statement">}</error>
 
 Object f2(int i) throws Exception {
@@ -217,7 +217,7 @@ interface ii {}



- int f1() throws Exception {
+ int <error descr="Invalid return type">f1</error>() throws Exception {
 <error descr="Missing return statement">}</error>
 
 Object f2(int i) throws Exception {
@@ -421,7 +421,7 @@ interface ii {}



- int f1() throws Exception {
+ int <error descr="Invalid return type">f1</error>() throws Exception {
 <error descr="Missing return statement">}</error>
 
 Object f2(int i) throws Exception {
@@ -626,7 +626,7 @@ interface ii {}



- int f1() throws Exception {
+ int <error descr="Invalid return type">f1</error>() throws Exception {
 <error descr="Missing return statement">}</error>
 
 Object f2(int i) throws Exception {
@@ -829,7 +829,7 @@ interface ii {}



- int f1() throws Exception {
+ int <error descr="Invalid return type">f1</error>() throws Exception {
 <error descr="Missing return statement">}</error>
 
 Object f2(int i) throws Exception {
@@ -1,12 +1,12 @@
 class s {
-  void f() {
+  void <error descr="Invalid return type">f</error>() {
    <error descr="Cannot return a value from a method with void result type">return 0;</error>
  }
  void f2() {
    return;
  }

-  int f3() {
+  int <error descr="Invalid return type">f3</error>() {
    <error descr="Missing return value">return;</error>
  }
  int f4() {
@@ -6,7 +6,7 @@ class Test {
    <warning descr="Unchecked call to 'isAssignableFrom(Class<?>)' as a member of raw type 'java.lang.Class'">foo.isAssignableFrom</warning>(Object.class);
  }

-  public List<String> transform(List<List<String>> result) {
+  public List<String> <error descr="Invalid return type">transform</error>(List<List<String>> result) {
    <error descr="Incompatible types. Found: 'java.util.List<java.util.List<java.lang.String>>', required: 'java.util.List<java.lang.String>'">return result;</error>
  }
 }
@@ -2,7 +2,7 @@ class Test {
        public <T> T doStuff() {
                return null;
        }
-        public boolean test() {
+        public boolean <error descr="Invalid return type">test</error>() {
                <error descr="Incompatible types. Found: 'java.lang.Object', required: 'boolean'">return doStuff();</error>
        }
        
@@ -9,7 +9,7 @@ public class WrongGenerics {
  }

  @SuppressWarnings("unchecked")
-  <T> Set<Foo<? extends T>> bar(Set<Foo<? extends T>> foo) {
+  <T> Set<Foo<? extends T>> <error descr="Invalid return type">bar</error>(Set<Foo<? extends T>> foo) {
    return <error descr="Inconvertible types; cannot cast 'java.util.Set<Foo<? extends T>>' to 'java.util.Set<Foo<?>>'">(Set<Foo<?>>) foo</error>;
  }

@@ -1,5 +1,5 @@
 class Bug {
-    static A test(A[] as) {
+    static A <error descr="Invalid return type">test</error>(A[] as) {
        for (<error descr="Incompatible types. Found: 'Bug.B', required: 'Bug.A'">B b</error> : as) {
            <error descr="Incompatible types. Found: 'Bug.B', required: 'Bug.A'">return b;</error>
        }
@@ -12,7 +12,7 @@ class B<S> extends A<S> {

 <error descr="'foo(T, S)' in 'A' clashes with 'foo(Object, Object)' in 'B'; both methods have same erasure, yet neither overrides the other">class C extends B<String></error> {
    @Override
-    <T> T foo(T x, String y) {
+    <T> T <error descr="Invalid return type">foo</error>(T x, String y) {
        <error descr="Incompatible types. Found: 'java.lang.Object', required: 'T'">return super.foo(x, y);</error>
    }
 }
@@ -16,7 +16,7 @@ class LimitedPool<T> {
    void cleanup(T t);
  }

-  public T alloc() {
+  public T <error descr="Invalid return type">alloc</error>() {
    if (index >= capacity) return factory.create();

    if (storage[index] == null) {
@@ -76,7 +76,7 @@ class d {
 }

 class e {
-    String foo () {
+    String <error descr="Invalid return type">foo</error> () {
        MyList myList = new MyList();
        <error descr="Incompatible types. Found: 'java.lang.Object', required: 'java.lang.String'">return myList.get(0);</error>
    }
@@ -128,7 +128,7 @@ class A111<T> {
    return v;
  }

-  String g(A111 a) {
+  String <error descr="Invalid return type">g</error>(A111 a) {
    //noinspection unchecked
    <error descr="Incompatible types. Found: 'java.lang.Object', required: 'java.lang.String'">return a.f("");</error>
  }
@@ -151,7 +151,7 @@ class A11<T> extends A1 {
 class Test1<X> {
  X x;
  java.util.ArrayList<Number> foo = new java.util.ArrayList<Number>();
-  public static Number foo() {
+  public static Number <error descr="Invalid return type">foo</error>() {
    <error descr="Incompatible types. Found: 'java.lang.Object', required: 'java.lang.Number'">return new Test1().foo.get(0);</error>
  }
 }
@@ -4,7 +4,7 @@ import java.util.stream.Collectors;
 import java.util.stream.Stream;

 class Test {
-  public static <Om> List<Om> sort(Comparator comp, Stream<Om> stream) {
+  public static <Om> List<Om> <error descr="Invalid return type">sort</error>(Comparator comp, Stream<Om> stream) {
    <error descr="Incompatible types. Found: 'java.lang.Object', required: 'java.util.List<Om>'">return stream.sorted(comp).collect(Collectors.toList());</error>
  }

@@ -1,5 +1,5 @@
 class Foo<T extends Enum> {
-  public T bar(Class<? extends T> type, String str) {
+  public T <error descr="Invalid return type">bar</error>(Class<? extends T> type, String str) {
    return <error descr="Incompatible types. Required T but 'valueOf' was inferred to T:
 Incompatible types: Enum is not convertible to T">Enum.valueOf(type, str);</error>
  }
@@ -12,7 +12,7 @@ class B<S> extends A<S> {

 <error descr="'foo(T, S)' in 'A' clashes with 'foo(Object, Object)' in 'B'; both methods have same erasure, yet neither overrides the other">class C extends B<String></error> {
    @Override
-    <T> T foo(T x, String y) {
+    <T> T <error descr="Invalid return type">foo</error>(T x, String y) {
        <error descr="Incompatible types. Found: 'java.lang.Object', required: 'T'">return super.foo(x, y);</error>
    }
 }
@@ -16,7 +16,7 @@ class LimitedPool<T> {
    void cleanup(T t);
  }

-  public T alloc() {
+  public T <error descr="Invalid return type">alloc</error>() {
    if (index >= capacity) return factory.create();

    if (storage[index] == null) {
@@ -87,7 +87,7 @@ class d {
 }

 class e {
-    String foo () {
+    String <error descr="Invalid return type">foo</error> () {
        MyList myList = new MyList();
        <error descr="Incompatible types. Found: 'java.lang.Object', required: 'java.lang.String'">return myList.get(0);</error>
    }
@@ -139,7 +139,7 @@ class A111<T> {
    return v;
  }

-  String g(A111 a) {
+  String <error descr="Invalid return type">g</error>(A111 a) {
    //noinspection unchecked
    <error descr="Incompatible types. Found: 'java.lang.Object', required: 'java.lang.String'">return a.f("");</error>
  }
@@ -162,7 +162,7 @@ class A11<T> extends A1 {
 class Test1<X> {
  X x;
  java.util.ArrayList<Number> foo = new java.util.ArrayList<Number>();
-  public static Number foo() {
+  public static Number <error descr="Invalid return type">foo</error>() {
    <error descr="Incompatible types. Found: 'java.lang.Object', required: 'java.lang.Number'">return new Test1().foo.get(0);</error>
  }
 }
@@ -3,7 +3,7 @@ abstract class Group {
  public Group() {
  }

-  public <T extends Category> T get(Key<T> key) {
+  public <T extends Category> T <error descr="Invalid return type">get</error>(Key<T> key) {
    return <error descr="Incompatible types. Required T but 'getCategory' was inferred to R:
 Incompatible types: Category is not convertible to T">getCategory(key);</error>
  }
@@ -1,6 +1,6 @@
 class Outer<T> {
    class Inner { }
-    Foo<Outer.Inner> m(Foo<Outer<Integer>.Inner> foo) {
+    Foo<Outer.Inner> <error descr="Invalid return type">m</error>(Foo<Outer<Integer>.Inner> foo) {
        <error descr="Incompatible types. Found: 'Foo<Outer<java.lang.Integer>.Inner>', required: 'Foo<Outer.Inner>'">return foo;</error>
    }
 }
@@ -6,7 +6,7 @@ class Test {
    return list.stream().flatMap(List::stream).collect(Collectors.toList());
  }

-  private static List<Object> test1(List<List> list) {
+  private static List<Object> <error descr="Invalid return type">test1</error>(List<List> list) {
    <error descr="Incompatible types. Found: 'java.lang.Object', required: 'java.util.List<java.lang.Object>'">return list.stream().flatMap(l -> l.stream()).collect(Collectors.toList());</error>
  }
 }
@@ -26,7 +26,7 @@ public class ConcurrentCollectors {
    }

    static class Test3 {
-        static <T, K, D, M1 extends Map<K, D>> C<T, M1> groupingBy(F<M1> f,
+        static <T, K, D, M1 extends Map<K, D>> C<T, M1> <error descr="Invalid return type">groupingBy</error>(F<M1> f,
                                                                   C<T, D> c,
                                                                   BiConsumer<M1, T> consumer) {
            return new CImpl<error descr="Cannot infer arguments"><></error>(f, consumer, arg(c.getOp()));
@@ -11,7 +11,7 @@ interface Foo<T> {
 }

 class Bar {
-  Foo<List<String>> transform(final Foo<? extends String> foo) {
+  Foo<List<String>> <error descr="Invalid return type">transform</error>(final Foo<? extends String> foo) {
    <error descr="Incompatible types. Found: 'Foo<? extends java.util.List<? extends java.lang.String>>', required: 'Foo<java.util.List<java.lang.String>>'">return foo
      .map(v2 -> tuple(v2))
      .onClose();</error>
@@ -3,7 +3,7 @@ import java.util.Map;
 import java.util.stream.Collectors;

 class MyTest {
-  static Map<String, Meeting> getMeetingsById(List<Meeting> meetings){
+  static Map<String, Meeting> <error descr="Invalid return type">getMeetingsById</error>(List<Meeting> meetings){
    return <error descr="Incompatible types. Required Map<String, Meeting> but 'collect' was inferred to R:
 no instance(s) of type variable(s) A, A, K, R, T exist so that List<T> conforms to Meeting">meetings.stream()
      .collect(Collectors.groupingBy(Meeting::getId));</error>
@@ -0,0 +1,11 @@
+// "Make 'm' return 'java.util.AbstractList<java.lang.Object>' or predecessor" "true"
+import java.util.*;
+
+class Test {
+
+  AbstractList<Object> m(boolean b) {
+    if (b) return new ArrayList<>();
+    return new LinkedList<>();
+  }
+
+}
@@ -0,0 +1,10 @@
+// "Make 'm' return 'java.lang.Integer' or predecessor" "true"
+
+class Test {
+
+  Integer m(boolean b) {
+    if (b) return null;
+    return 42;
+  }
+
+}
@@ -0,0 +1,9 @@
+// "Make 'm' return 'int'" "true"
+
+class Test {
+
+  int m() {
+    return 42;
+  }
+
+}
@@ -0,0 +1,8 @@
+// "Make 'm' return 'void'" "true"
+
+class Test {
+
+  void m() {
+  }
+
+}
@@ -0,0 +1,9 @@
+// "Make 'm' return 'double'" "true"
+class Test {
+
+  double m(boolean b) {
+    if (b) return 42;
+    return 10.0;
+  }
+
+}
@@ -2,7 +2,7 @@

 class Test {

-  <caret><selection>Object</selection> foo() {
+  Object foo() {
    return null;
  }
 }
@@ -0,0 +1,11 @@
+// "Make 'm' return 'java.util.AbstractList<java.lang.Object>' or predecessor" "true"
+import java.util.*;
+
+class Test {
+
+  void <caret>m(boolean b) {
+    if (b) return new ArrayList<>();
+    return new LinkedList<>();
+  }
+
+}
@@ -0,0 +1,10 @@
+// "Make 'm' return 'java.lang.Integer' or predecessor" "true"
+
+class Test {
+
+  void <caret>m(boolean b) {
+    if (b) return null;
+    return 42;
+  }
+
+}
@@ -0,0 +1,9 @@
+// "Make 'm' return 'int'" "true"
+
+class Test {
+
+  void <caret>m() {
+    return 42;
+  }
+
+}
@@ -0,0 +1,8 @@
+// "Make 'm' return 'void'" "true"
+
+class Test {
+
+  int <caret>m() {
+  }
+
+}
@@ -0,0 +1,9 @@
+// "Make 'm' return 'double'" "true"
+class Test {
+
+  <caret>m(boolean b) {
+    if (b) return 42;
+    return 10.0;
+  }
+
+}