Merge pull request microsoft#8770 from Microsoft/apparent-members-for-type-parameters-constrained-by-any

Apparent members for type parameters constrained by any

Author: sandersn

src/compiler/checker.ts

@@ -9955,9 +9955,9 @@ namespace ts {
             }
 
             const apparentType = getApparentType(getWidenedType(type));
-            if (apparentType === unknownType) {
-                // handle cases when type is Type parameter with invalid constraint
-                return unknownType;
+            if (apparentType === unknownType || (type.flags & TypeFlags.TypeParameter && isTypeAny(apparentType))) {
+                // handle cases when type is Type parameter with invalid or any constraint
+                return apparentType;
             }
             const prop = getPropertyOfType(apparentType, right.text);
             if (!prop) {
@@ -11148,7 +11148,9 @@ namespace ts {
             // types are provided for the argument expressions, and the result is always of type Any.
             // We exclude union types because we may have a union of function types that happen to have
             // no common signatures.
-            if (isTypeAny(funcType) || (!callSignatures.length && !constructSignatures.length && !(funcType.flags & TypeFlags.Union) && isTypeAssignableTo(funcType, globalFunctionType))) {
+            if (isTypeAny(funcType) ||
+                (isTypeAny(apparentType) && funcType.flags & TypeFlags.TypeParameter) ||
+                (!callSignatures.length && !constructSignatures.length && !(funcType.flags & TypeFlags.Union) && isTypeAssignableTo(funcType, globalFunctionType))) {
                 // The unknownType indicates that an error already occurred (and was reported).  No
                 // need to report another error in this case.
                 if (funcType !== unknownType && node.typeArguments) {

tests/baselines/reference/typeParameterExplicitlyExtendsAny.errors.txt

@@ -1,9 +1,7 @@
 tests/cases/compiler/typeParameterExplicitlyExtendsAny.ts(3,7): error TS2339: Property 'blah' does not exist on type 'T'.
-tests/cases/compiler/typeParameterExplicitlyExtendsAny.ts(9,7): error TS2339: Property 'blah' does not exist on type 'T'.
-tests/cases/compiler/typeParameterExplicitlyExtendsAny.ts(10,7): error TS2339: Property 'toString' does not exist on type 'T'.
 
 
-==== tests/cases/compiler/typeParameterExplicitlyExtendsAny.ts (3 errors) ====
+==== tests/cases/compiler/typeParameterExplicitlyExtendsAny.ts (1 errors) ====
     function fee<T>() {
         var t: T;
         t.blah; // Error
@@ -14,10 +12,28 @@ tests/cases/compiler/typeParameterExplicitlyExtendsAny.ts(10,7): error TS2339: P
 
     function fee2<T extends any>() {
         var t: T;
-        t.blah; // Error
-          ~~~~
-!!! error TS2339: Property 'blah' does not exist on type 'T'.
+        t.blah; // ok
         t.toString; // ok
-          ~~~~~~~~
-!!! error TS2339: Property 'toString' does not exist on type 'T'.
-    }
+    }
+    
+    function f<T extends any>(x: T) {
+        x.children;
+        x();
+        new x();
+        x[100];
+        x['hello'];
+    }
+    
+    
+    // Generic Tree structure
+    type Tree<T> = T & {
+        children?: Tree<T>[];
+    }
+    
+    class MyClass {
+        public static displayTree1<T extends Tree<any>>(tree: T) {
+            // error "Property 'children' does not exist on type 'T'"
+            tree.children;
+        }
+    }
+    

tests/baselines/reference/typeParameterExplicitlyExtendsAny.js

@@ -7,9 +7,31 @@ function fee<T>() {
 
 function fee2<T extends any>() {
     var t: T;
-    t.blah; // Error
+    t.blah; // ok
     t.toString; // ok
-}
+}
+
+function f<T extends any>(x: T) {
+    x.children;
+    x();
+    new x();
+    x[100];
+    x['hello'];
+}
+
+
+// Generic Tree structure
+type Tree<T> = T & {
+    children?: Tree<T>[];
+}
+
+class MyClass {
+    public static displayTree1<T extends Tree<any>>(tree: T) {
+        // error "Property 'children' does not exist on type 'T'"
+        tree.children;
+    }
+}
+
 
 //// [typeParameterExplicitlyExtendsAny.js]
 function fee() {
@@ -19,6 +41,22 @@ function fee() {
 }
 function fee2() {
     var t;
-    t.blah; // Error
+    t.blah; // ok
     t.toString; // ok
 }
+function f(x) {
+    x.children;
+    x();
+    new x();
+    x[100];
+    x['hello'];
+}
+var MyClass = (function () {
+    function MyClass() {
+    }
+    MyClass.displayTree1 = function (tree) {
+        // error "Property 'children' does not exist on type 'T'"
+        tree.children;
+    };
+    return MyClass;
+}());

tests/cases/compiler/typeParameterExplicitlyExtendsAny.ts

@@ -6,6 +6,27 @@ function fee<T>() {
 
 function fee2<T extends any>() {
     var t: T;
-    t.blah; // Error
+    t.blah; // ok
     t.toString; // ok
-}
+}
+
+function f<T extends any>(x: T) {
+    x.children;
+    x();
+    new x();
+    x[100];
+    x['hello'];
+}
+
+
+// Generic Tree structure
+type Tree<T> = T & {
+    children?: Tree<T>[];
+}
+
+class MyClass {
+    public static displayTree1<T extends Tree<any>>(tree: T) {
+        // error "Property 'children' does not exist on type 'T'"
+        tree.children;
+    }
+}