Addressing CR feedback

Author: ahejlsberg

src/compiler/checker.ts

@@ -4073,8 +4073,7 @@ module ts {
                             inferFromTypes(source, t);
                         }
                     }
-                    // If no inferences were produced above and union contains a single naked type parameter,
-                    // make a secondary inference to that type parameter
+                    // If union contains a single naked type parameter, make a secondary inference to that type parameter
                     if (typeParameterCount === 1) {
                         inferiority++;
                         inferFromTypes(source, typeParameter);

tests/cases/conformance/types/typeRelationships/typeInference/unionTypeInference.ts

@@ -4,17 +4,28 @@
 function f<T>(x: T, y: string|T): T {
     return x;
 }
+
+var a1: number;
+var a1 = f(1, 2);
+var a2: number;
+var a2 = f(1, "hello");
+var a3: number;
+var a3 = f(1, a1 || "hello");
+var a4: any;
+var a4 = f(undefined, "abc");
+
 function g<T>(value: [string, T]): T {
     return value[1];
 }
 
-var a: number;
-var a = f(1, 2);
-var b: number;
-var b = f(1, "hello");
-var c: number;
-var c = f(1, a || "hello");
-var d: any;
-var d = f(undefined, "abc");
-var e: boolean;
-var e = g(["string", true]);
+var b1: boolean;
+var b1 = g(["string", true]);
+
+function h<T>(x: string|boolean|T): T {
+    return typeof x === "string" || typeof x === "boolean" ? undefined : x;
+}
+
+var c1: number;
+var c1 = h(5);
+var c2: string;
+var c2 = h("abc");