Fixes #3217: Lambdas: use erased type. (#3252)

typetools · Apr 30, 2020 · e38f895 · e38f895
1 parent 33b3e18
commit e38f895
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Showing 2 changed files with 26 additions and 3 deletions.
diff --git a/checker/tests/nullness/java8/lambda/Issue3217.java b/checker/tests/nullness/java8/lambda/Issue3217.java
@@ -0,0 +1,20 @@
+import java.util.function.Function;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public class Issue3217<ModelA, ModelB, Value> {
+    private final Function<Function<ModelA, @Nullable Value>, Function<ModelB, @Nullable Value>>
+            proxyFunction;
+
+    public Issue3217(
+            Function<Function<ModelA, @Nullable Value>, Function<ModelB, @Nullable Value>>
+                    proxyFunction) {
+        this.proxyFunction = proxyFunction;
+    }
+}
+
+class SubClass<A, V> extends Issue3217<A, A, V> {
+    public SubClass() {
+        super(x -> x);
+        Function<Function<A, @Nullable V>, Function<A, @Nullable V>> p = y -> y;
+    }
+}
diff --git a/framework/src/main/java/org/checkerframework/framework/type/TypeFromMemberVisitor.java b/framework/src/main/java/org/checkerframework/framework/type/TypeFromMemberVisitor.java
@@ -15,6 +15,7 @@
 import org.checkerframework.framework.util.AnnotatedTypes;
 import org.checkerframework.javacutil.AnnotationUtils;
 import org.checkerframework.javacutil.TreeUtils;
+import org.checkerframework.javacutil.TypesUtils;
 
 /**
  * Converts a field or methods tree into an AnnotatedTypeMirror.
@@ -100,9 +101,11 @@ private static AnnotatedTypeMirror inferLambdaParamAnnotations(
             AnnotatedExecutableType functionType = f.getFunctionTypeFromTree(lambdaDecl);
             AnnotatedTypeMirror funcTypeParam = functionType.getParameterTypes().get(index);
             if (TreeUtils.isImplicitlyTypedLambda(declaredInTree)) {
-                if (f.types.isSubtype(funcTypeParam.actualType, lambdaParam.actualType)) {
-                    // The Java types should be exactly the same, but because invocation type
-                    // inference (#979) isn't implement, check first.
+                // The Java types should be exactly the same, but because invocation type
+                // inference (#979) isn't implement, check first. Use the erased types because the
+                // type arguments are not substituted when the annotated type arguments are.
+                if (TypesUtils.isErasedSubtype(
+                        funcTypeParam.actualType, lambdaParam.actualType, f.types)) {
                     return AnnotatedTypes.asSuper(f, funcTypeParam, lambdaParam);
                 }
                 lambdaParam.addMissingAnnotations(funcTypeParam.getAnnotations());