Match JavaType.GenericTypeVariable in TypeUtils#isAssignableTo() (#…

…3655) Fix the assignability test for generic type variable types.
openrewrite · Nov 2, 2023 · 30a74ee · 30a74ee
1 parent 8bdf967
commit 30a74ee
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Showing 2 changed files with 38 additions and 3 deletions.
diff --git a/rewrite-java-tck/src/main/java/org/openrewrite/java/tree/TypeUtilsTest.java b/rewrite-java-tck/src/main/java/org/openrewrite/java/tree/TypeUtilsTest.java
@@ -245,4 +245,36 @@ public J.VariableDeclarations.NamedVariable visitVariable(J.VariableDeclarations
           )
         );
     }
+
+    @Test
+    void isAssignableToGenericTypeVariable() {
+        rewriteRun(
+          java(
+            """
+              import java.util.Map;
+              import java.util.function.Supplier;
+              
+              class Test {
+                  <K, V> void m(Supplier<? extends Map<K, ? extends V>> map) {
+                  }
+                  void foo() {
+                      Map<String, Integer> map = null;
+                      m(() -> map);
+                  }
+              }
+              """,
+            spec -> spec.afterRecipe(cu -> new JavaIsoVisitor<>() {
+                @Override
+                public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, Object o) {
+                    JavaType paramType = method.getMethodType().getParameterTypes().get(0);
+                    assertThat(paramType).isInstanceOf(JavaType.Parameterized.class);
+                    JavaType argType = method.getArguments().get(0).getType();
+                    assertThat(argType).isInstanceOf(JavaType.Parameterized.class);
+                    assertThat(TypeUtils.isAssignableTo(paramType, argType)).isTrue();
+                    return method;
+                }
+            }.visit(cu, new InMemoryExecutionContext()))
+          )
+        );
+    }
 }
diff --git a/rewrite-java/src/main/java/org/openrewrite/java/tree/TypeUtils.java b/rewrite-java/src/main/java/org/openrewrite/java/tree/TypeUtils.java
@@ -202,9 +202,12 @@ public static boolean isAssignableTo(@Nullable JavaType to, @Nullable JavaType f
                 JavaType.FullyQualified toFq = (JavaType.FullyQualified) to;
                 return isAssignableTo(toFq.getFullyQualifiedName(), from);
             } else if (to instanceof JavaType.GenericTypeVariable) {
-                JavaType.GenericTypeVariable genericTo = (JavaType.GenericTypeVariable) to;
-                if (genericTo.getBounds().isEmpty()) {
-                    return genericTo.getName().equals("?");
+                JavaType.GenericTypeVariable toGeneric = (JavaType.GenericTypeVariable) to;
+                List<JavaType> toBounds = toGeneric.getBounds();
+                if (toBounds.isEmpty()) {
+                    return toGeneric.getName().equals("?");
+                } else if (toBounds.size() == 1) {
+                    return isAssignableTo(toBounds.get(0), from);
                 }
                 return false;
             } else if (to instanceof JavaType.Variable) {