Merge pull request scala#41 from noti0na1/dotty-explicit-nulls

Change the way of creating ClassSymbol

Author: noti0na1

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -816,19 +816,21 @@ class Definitions {
   // A list of annotations that are commonly used to indicate that a field/method argument or return
   // type is not null. These annotations are used by the nullification logic in JavaNullInterop to
   // improve the precision of type nullification.
-  @tu lazy val NotNullAnnots: List[ClassSymbol] =
-    ("javax.annotation.Nonnull" ::
-      "edu.umd.cs.findbugs.annotations.NonNull" ::
-      "androidx.annotation.NonNull" ::
-      "android.support.annotation.NonNull" ::
-      "android.annotation.NonNull" ::
-      "com.android.annotations.NonNull" ::
-      "org.eclipse.jdt.annotation.NonNull" ::
-      "org.checkerframework.checker.nullness.qual.NonNull" ::
-      "org.checkerframework.checker.nullness.compatqual.NonNullDecl" ::
-      "org.jetbrains.annotations.NotNull" ::
-      "lombok.NonNull" ::
-      "io.reactivex.annotations.NonNull" :: Nil).map(ctx.requiredClass(_))
+  // We don't require that any of these annotations be present in the class path, but we want to
+  // create Symbols for the ones that are present, so they can be checked during nullification.
+  @tu lazy val NotNullAnnots: List[ClassSymbol] = ctx.getClassesIfDefined(
+    "javax.annotation.Nonnull" ::
+    "edu.umd.cs.findbugs.annotations.NonNull" ::
+    "androidx.annotation.NonNull" ::
+    "android.support.annotation.NonNull" ::
+    "android.annotation.NonNull" ::
+    "com.android.annotations.NonNull" ::
+    "org.eclipse.jdt.annotation.NonNull" ::
+    "org.checkerframework.checker.nullness.qual.NonNull" ::
+    "org.checkerframework.checker.nullness.compatqual.NonNullDecl" ::
+    "org.jetbrains.annotations.NotNull" ::
+    "lombok.NonNull" ::
+    "io.reactivex.annotations.NonNull" :: Nil map PreNamedString)
 
   // convenient one-parameter method types
   def methOfAny(tp: Type): MethodType = MethodType(List(AnyType), tp)

compiler/src/dotty/tools/dotc/core/Symbols.scala

@@ -383,6 +383,15 @@ trait Symbols { this: Context =>
       .requiredSymbol("class", name, generateStubs = false)(_.isClass)
   }
 
+  /** Get a List of ClassSymbols which are either defined in current compilation
+   *  run or present on classpath.
+   */
+  def getClassesIfDefined(pathes: List[PreName]): List[ClassSymbol] =
+    pathes.foldLeft(List.empty){ case (acc, path) => getClassIfDefined(path) match {
+      case cls: ClassSymbol => cls :: acc
+      case _ => acc
+    }}
+
   /** Get ClassSymbol if package is either defined in current compilation run
    *  or present on classpath.
    *  Returns NoSymbol otherwise. */

tests/explicit-nulls/neg/notnull/J.java

@@ -0,0 +1,15 @@
+import java.util.*;
+import notnull.NotNull;
+
+public class J {
+
+    private static String getK() {
+        return "k";
+    }
+
+    @NotNull
+    public static final String k = getK();
+
+    @NotNull
+    public static String l = "l";
+}

tests/explicit-nulls/neg/notnull/NotNull.java

@@ -0,0 +1,8 @@
+package notnull;
+
+import java.lang.annotation.*;
+
+// A NotNull Annotation not in the list
+@Retention(value = RetentionPolicy.RUNTIME)
+public @interface NotNull {
+}

tests/explicit-nulls/neg/notnull/S.scala

@@ -0,0 +1,7 @@
+// Test that NotNull annotations not in the list are not working in Java files.
+
+class S {
+  def kk: String = J.k // error: k doesn't have a constant type and the NotNull annotation is not in the list
+
+  def ll: String = J.l // error: the NotNull annotation is not in the list
+}

tests/explicit-nulls/pos/notnull/J.java

@@ -3,9 +3,12 @@
 
 public class J {
 
+    private static String getK() {
+        return "k";
+    }
+
     @Nonnull
-    // JavaParser will never assign ConstantType to fields currently.
-    public static final String k = "k";
+    public static final String k = getK();
 
     @Nonnull
     public static String l = "l";