Allow calling functions whose "this type" is top or undefined as fr…

…ee functions. Example: ``` class Foo { /** @this {*} */ method() { } } const x = Foo.method; x(); // This is legal now. ``` ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=244935076
google · Apr 24, 2019 · a15f21f · a15f21f
1 parent 7db0af3
commit a15f21f
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Showing 2 changed files with 16 additions and 12 deletions.
diff --git a/src/com/google/javascript/jscomp/TypeCheck.java b/src/com/google/javascript/jscomp/TypeCheck.java
@@ -2554,14 +2554,17 @@ private void visitCall(NodeTraversal t, Node n) {
         report(n, CONSTRUCTOR_NOT_CALLABLE, childType.toString());
       }
 
-      // Functions with explicit 'this' types must be called in a GETPROP
-      // or GETELEM.
-      if (functionType.isOrdinaryFunction()
-          && !functionType.getTypeOfThis().isUnknownType()
-          && !(functionType.getTypeOfThis().toObjectType() != null
-              && functionType.getTypeOfThis().toObjectType().isNativeObjectType())
-          && !(child.isGetElem() || child.isGetProp())) {
-        report(n, EXPECTED_THIS_TYPE, functionType.toString());
+      // Functions with explicit 'this' types must be called in a GETPROP or GETELEM.
+      if (functionType.isOrdinaryFunction() && !NodeUtil.isGet(child)) {
+        JSType receiverType = functionType.getTypeOfThis();
+        if (receiverType.isUnknownType()
+            || receiverType.isAllType()
+            || receiverType.isVoidType()
+            || (receiverType.isObjectType() && receiverType.toObjectType().isNativeObjectType())) {
+          // Allow these special cases.
+        } else {
+          report(n, EXPECTED_THIS_TYPE, functionType.toString());
+        }
       }
 
       visitArgumentList(n, functionType);

diff --git a/test/com/google/javascript/jscomp/TypeCheckTest.java b/test/com/google/javascript/jscomp/TypeCheckTest.java
@@ -8525,10 +8525,11 @@ public void testThis14() {
   }
 
   @Test
-  public void testThisTypeOfFunction1() {
-    testTypes(
-        "/** @type {function(this:Object)} */ function f() {}" +
-        "f();");
+  public void testThisType_whichTypesSupport_freeCallsOfFunction() {
+    testTypes("/** @type {function(this:*)} */ function f() {}; f();");
+    testTypes("/** @type {function(this:?)} */ function f() {}; f();");
+    testTypes("/** @type {function(this:undefined)} */ function f() {}; f();");
+    testTypes("/** @type {function(this:Object)} */ function f() {}; f();");
   }
 
   @Test