From 1c8b30482659f7b27013f2faa9944d9bb18b8b23 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Thu, 4 Oct 2018 09:22:46 -0700
Subject: [PATCH 1/3] narrowTypeByInstanceof understands ctor funcs

---
 src/compiler/checker.ts                       |   9 +-
 .../reference/controlFlowInstanceof.js        | 196 ------------------
 .../reference/controlFlowInstanceof.symbols   | 195 +++++++++--------
 .../reference/controlFlowInstanceof.types     |  30 ++-
 tests/cases/compiler/controlFlowInstanceof.ts |  14 ++
 5 files changed, 159 insertions(+), 285 deletions(-)
 delete mode 100644 tests/baselines/reference/controlFlowInstanceof.js

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 21518ca34d54e..160570c424759 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -15391,9 +15391,12 @@ namespace ts {
                 }
 
                 if (!targetType) {
-                    const constructSignatures = getSignaturesOfType(rightType, SignatureKind.Construct);
-                    targetType = constructSignatures && constructSignatures.length ?
-                        getUnionType(map(constructSignatures, signature => getReturnTypeOfSignature(getErasedSignature(signature)))) :
+                    let constructSignatures = getSignaturesOfType(rightType, SignatureKind.Construct);
+                    if(constructSignatures.length === 0) {
+                        constructSignatures = filter(getSignaturesOfType(rightType, SignatureKind.Call), sig => isJSConstructor(sig.declaration));
+                    }
+                    targetType = constructSignatures.length ?
+                        getUnionType(map(constructSignatures, signature => isJSConstructor(signature.declaration) && getJSClassType(getSymbolOfNode(signature.declaration!)) || getReturnTypeOfSignature(getErasedSignature(signature)))) :
                         emptyObjectType;
                 }
 
diff --git a/tests/baselines/reference/controlFlowInstanceof.js b/tests/baselines/reference/controlFlowInstanceof.js
deleted file mode 100644
index 1ac63f138f6e8..0000000000000
--- a/tests/baselines/reference/controlFlowInstanceof.js
+++ /dev/null
@@ -1,196 +0,0 @@
-//// [controlFlowInstanceof.ts]
-// Repros from #10167
-
-function f1(s: Set<string> | Set<number>) {
-    s = new Set<number>();
-    s;  // Set<number>
-    if (s instanceof Set) {
-        s;  // Set<number>
-    }
-    s;  // Set<number>
-    s.add(42);
-}
-
-function f2(s: Set<string> | Set<number>) {
-    s = new Set<number>();
-    s;  // Set<number>
-    if (s instanceof Promise) {
-        s;  // Set<number> & Promise<any>
-    }
-    s;  // Set<number>
-    s.add(42);
-}
-
-function f3(s: Set<string> | Set<number>) {
-    s;  // Set<string> | Set<number>
-    if (s instanceof Set) {
-        s;  // Set<string> | Set<number>
-    }
-    else {
-        s;  // never
-    }
-}
-
-function f4(s: Set<string> | Set<number>) {
-    s = new Set<number>();
-    s;  // Set<number>
-    if (s instanceof Set) {
-        s;  // Set<number>
-    }
-    else {
-        s;  // never
-    }
-}
-
-// More tests
-
-class A { a: string }
-class B extends A { b: string }
-class C extends A { c: string }
-
-function foo(x: A | undefined) {
-    x;  // A | undefined
-    if (x instanceof B || x instanceof C) {
-        x;  // B | C
-    }
-    x;  // A | undefined
-    if (x instanceof B && x instanceof C) {
-        x;  // B & C
-    }
-    x;  // A | undefined
-    if (!x) {
-        return;
-    }
-    x;  // A
-    if (x instanceof B) {
-        x;  // B
-        if (x instanceof C) {
-            x;  // B & C
-        }
-        else {
-            x;  // B
-        }
-        x;  // B
-    }
-    else {
-        x;  // A
-    }
-    x;  // A
-}
-
-// X is neither assignable to Y nor a subtype of Y
-// Y is assignable to X, but not a subtype of X
-
-interface X {
-    x?: string;
-}
-
-class Y {
-    y: string;
-}
-
-function goo(x: X) {
-    x;
-    if (x instanceof Y) {
-        x.y;
-    }
-    x;
-}
-
-// Repro from #27282
-
-declare const x: (() => void)|null;
-declare const ctor: Function;
-
-if (x instanceof ctor) {
-    x();
-}
-
-
-//// [controlFlowInstanceof.js]
-// Repros from #10167
-function f1(s) {
-    s = new Set();
-    s; // Set<number>
-    if (s instanceof Set) {
-        s; // Set<number>
-    }
-    s; // Set<number>
-    s.add(42);
-}
-function f2(s) {
-    s = new Set();
-    s; // Set<number>
-    if (s instanceof Promise) {
-        s; // Set<number> & Promise<any>
-    }
-    s; // Set<number>
-    s.add(42);
-}
-function f3(s) {
-    s; // Set<string> | Set<number>
-    if (s instanceof Set) {
-        s; // Set<string> | Set<number>
-    }
-    else {
-        s; // never
-    }
-}
-function f4(s) {
-    s = new Set();
-    s; // Set<number>
-    if (s instanceof Set) {
-        s; // Set<number>
-    }
-    else {
-        s; // never
-    }
-}
-// More tests
-class A {
-}
-class B extends A {
-}
-class C extends A {
-}
-function foo(x) {
-    x; // A | undefined
-    if (x instanceof B || x instanceof C) {
-        x; // B | C
-    }
-    x; // A | undefined
-    if (x instanceof B && x instanceof C) {
-        x; // B & C
-    }
-    x; // A | undefined
-    if (!x) {
-        return;
-    }
-    x; // A
-    if (x instanceof B) {
-        x; // B
-        if (x instanceof C) {
-            x; // B & C
-        }
-        else {
-            x; // B
-        }
-        x; // B
-    }
-    else {
-        x; // A
-    }
-    x; // A
-}
-class Y {
-}
-function goo(x) {
-    x;
-    if (x instanceof Y) {
-        x.y;
-    }
-    x;
-}
-if (x instanceof ctor) {
-    x();
-}
diff --git a/tests/baselines/reference/controlFlowInstanceof.symbols b/tests/baselines/reference/controlFlowInstanceof.symbols
index 72ab32d29d52d..df3c552eb2ea9 100644
--- a/tests/baselines/reference/controlFlowInstanceof.symbols
+++ b/tests/baselines/reference/controlFlowInstanceof.symbols
@@ -1,249 +1,274 @@
-=== tests/cases/compiler/controlFlowInstanceof.ts ===
+=== tests/cases/compiler/ts.ts ===
 // Repros from #10167
 
 function f1(s: Set<string> | Set<number>) {
->f1 : Symbol(f1, Decl(controlFlowInstanceof.ts, 0, 0))
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
+>f1 : Symbol(f1, Decl(ts.ts, 0, 0))
+>s : Symbol(s, Decl(ts.ts, 2, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s = new Set<number>();
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
+>s : Symbol(s, Decl(ts.ts, 2, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s;  // Set<number>
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
+>s : Symbol(s, Decl(ts.ts, 2, 12))
 
     if (s instanceof Set) {
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
+>s : Symbol(s, Decl(ts.ts, 2, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
         s;  // Set<number>
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
+>s : Symbol(s, Decl(ts.ts, 2, 12))
     }
     s;  // Set<number>
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
+>s : Symbol(s, Decl(ts.ts, 2, 12))
 
     s.add(42);
 >s.add : Symbol(Set.add, Decl(lib.es2015.collection.d.ts, --, --))
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
+>s : Symbol(s, Decl(ts.ts, 2, 12))
 >add : Symbol(Set.add, Decl(lib.es2015.collection.d.ts, --, --))
 }
 
 function f2(s: Set<string> | Set<number>) {
->f2 : Symbol(f2, Decl(controlFlowInstanceof.ts, 10, 1))
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
+>f2 : Symbol(f2, Decl(ts.ts, 10, 1))
+>s : Symbol(s, Decl(ts.ts, 12, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s = new Set<number>();
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
+>s : Symbol(s, Decl(ts.ts, 12, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s;  // Set<number>
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
+>s : Symbol(s, Decl(ts.ts, 12, 12))
 
     if (s instanceof Promise) {
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
+>s : Symbol(s, Decl(ts.ts, 12, 12))
 >Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
         s;  // Set<number> & Promise<any>
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
+>s : Symbol(s, Decl(ts.ts, 12, 12))
     }
     s;  // Set<number>
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
+>s : Symbol(s, Decl(ts.ts, 12, 12))
 
     s.add(42);
 >s.add : Symbol(Set.add, Decl(lib.es2015.collection.d.ts, --, --))
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
+>s : Symbol(s, Decl(ts.ts, 12, 12))
 >add : Symbol(Set.add, Decl(lib.es2015.collection.d.ts, --, --))
 }
 
 function f3(s: Set<string> | Set<number>) {
->f3 : Symbol(f3, Decl(controlFlowInstanceof.ts, 20, 1))
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 22, 12))
+>f3 : Symbol(f3, Decl(ts.ts, 20, 1))
+>s : Symbol(s, Decl(ts.ts, 22, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s;  // Set<string> | Set<number>
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 22, 12))
+>s : Symbol(s, Decl(ts.ts, 22, 12))
 
     if (s instanceof Set) {
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 22, 12))
+>s : Symbol(s, Decl(ts.ts, 22, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
         s;  // Set<string> | Set<number>
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 22, 12))
+>s : Symbol(s, Decl(ts.ts, 22, 12))
     }
     else {
         s;  // never
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 22, 12))
+>s : Symbol(s, Decl(ts.ts, 22, 12))
     }
 }
 
 function f4(s: Set<string> | Set<number>) {
->f4 : Symbol(f4, Decl(controlFlowInstanceof.ts, 30, 1))
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
+>f4 : Symbol(f4, Decl(ts.ts, 30, 1))
+>s : Symbol(s, Decl(ts.ts, 32, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s = new Set<number>();
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
+>s : Symbol(s, Decl(ts.ts, 32, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s;  // Set<number>
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
+>s : Symbol(s, Decl(ts.ts, 32, 12))
 
     if (s instanceof Set) {
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
+>s : Symbol(s, Decl(ts.ts, 32, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
         s;  // Set<number>
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
+>s : Symbol(s, Decl(ts.ts, 32, 12))
     }
     else {
         s;  // never
->s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
+>s : Symbol(s, Decl(ts.ts, 32, 12))
     }
 }
 
 // More tests
 
 class A { a: string }
->A : Symbol(A, Decl(controlFlowInstanceof.ts, 41, 1))
->a : Symbol(A.a, Decl(controlFlowInstanceof.ts, 45, 9))
+>A : Symbol(A, Decl(ts.ts, 41, 1))
+>a : Symbol(A.a, Decl(ts.ts, 45, 9))
 
 class B extends A { b: string }
->B : Symbol(B, Decl(controlFlowInstanceof.ts, 45, 21))
->A : Symbol(A, Decl(controlFlowInstanceof.ts, 41, 1))
->b : Symbol(B.b, Decl(controlFlowInstanceof.ts, 46, 19))
+>B : Symbol(B, Decl(ts.ts, 45, 21))
+>A : Symbol(A, Decl(ts.ts, 41, 1))
+>b : Symbol(B.b, Decl(ts.ts, 46, 19))
 
 class C extends A { c: string }
->C : Symbol(C, Decl(controlFlowInstanceof.ts, 46, 31))
->A : Symbol(A, Decl(controlFlowInstanceof.ts, 41, 1))
->c : Symbol(C.c, Decl(controlFlowInstanceof.ts, 47, 19))
+>C : Symbol(C, Decl(ts.ts, 46, 31))
+>A : Symbol(A, Decl(ts.ts, 41, 1))
+>c : Symbol(C.c, Decl(ts.ts, 47, 19))
 
 function foo(x: A | undefined) {
->foo : Symbol(foo, Decl(controlFlowInstanceof.ts, 47, 31))
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
->A : Symbol(A, Decl(controlFlowInstanceof.ts, 41, 1))
+>foo : Symbol(foo, Decl(ts.ts, 47, 31))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
+>A : Symbol(A, Decl(ts.ts, 41, 1))
 
     x;  // A | undefined
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
 
     if (x instanceof B || x instanceof C) {
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
->B : Symbol(B, Decl(controlFlowInstanceof.ts, 45, 21))
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
->C : Symbol(C, Decl(controlFlowInstanceof.ts, 46, 31))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
+>B : Symbol(B, Decl(ts.ts, 45, 21))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
+>C : Symbol(C, Decl(ts.ts, 46, 31))
 
         x;  // B | C
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
     }
     x;  // A | undefined
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
 
     if (x instanceof B && x instanceof C) {
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
->B : Symbol(B, Decl(controlFlowInstanceof.ts, 45, 21))
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
->C : Symbol(C, Decl(controlFlowInstanceof.ts, 46, 31))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
+>B : Symbol(B, Decl(ts.ts, 45, 21))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
+>C : Symbol(C, Decl(ts.ts, 46, 31))
 
         x;  // B & C
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
     }
     x;  // A | undefined
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
 
     if (!x) {
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
 
         return;
     }
     x;  // A
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
 
     if (x instanceof B) {
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
->B : Symbol(B, Decl(controlFlowInstanceof.ts, 45, 21))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
+>B : Symbol(B, Decl(ts.ts, 45, 21))
 
         x;  // B
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
 
         if (x instanceof C) {
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
->C : Symbol(C, Decl(controlFlowInstanceof.ts, 46, 31))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
+>C : Symbol(C, Decl(ts.ts, 46, 31))
 
             x;  // B & C
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
         }
         else {
             x;  // B
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
         }
         x;  // B
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
     }
     else {
         x;  // A
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
     }
     x;  // A
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>x : Symbol(x, Decl(ts.ts, 49, 13))
 }
 
 // X is neither assignable to Y nor a subtype of Y
 // Y is assignable to X, but not a subtype of X
 
 interface X {
->X : Symbol(X, Decl(controlFlowInstanceof.ts, 77, 1))
+>X : Symbol(X, Decl(ts.ts, 77, 1))
 
     x?: string;
->x : Symbol(X.x, Decl(controlFlowInstanceof.ts, 82, 13))
+>x : Symbol(X.x, Decl(ts.ts, 82, 13))
 }
 
 class Y {
->Y : Symbol(Y, Decl(controlFlowInstanceof.ts, 84, 1))
+>Y : Symbol(Y, Decl(ts.ts, 84, 1))
 
     y: string;
->y : Symbol(Y.y, Decl(controlFlowInstanceof.ts, 86, 9))
+>y : Symbol(Y.y, Decl(ts.ts, 86, 9))
 }
 
 function goo(x: X) {
->goo : Symbol(goo, Decl(controlFlowInstanceof.ts, 88, 1))
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 90, 13))
->X : Symbol(X, Decl(controlFlowInstanceof.ts, 77, 1))
+>goo : Symbol(goo, Decl(ts.ts, 88, 1))
+>x : Symbol(x, Decl(ts.ts, 90, 13))
+>X : Symbol(X, Decl(ts.ts, 77, 1))
 
     x;
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 90, 13))
+>x : Symbol(x, Decl(ts.ts, 90, 13))
 
     if (x instanceof Y) {
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 90, 13))
->Y : Symbol(Y, Decl(controlFlowInstanceof.ts, 84, 1))
+>x : Symbol(x, Decl(ts.ts, 90, 13))
+>Y : Symbol(Y, Decl(ts.ts, 84, 1))
 
         x.y;
->x.y : Symbol(Y.y, Decl(controlFlowInstanceof.ts, 86, 9))
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 90, 13))
->y : Symbol(Y.y, Decl(controlFlowInstanceof.ts, 86, 9))
+>x.y : Symbol(Y.y, Decl(ts.ts, 86, 9))
+>x : Symbol(x, Decl(ts.ts, 90, 13))
+>y : Symbol(Y.y, Decl(ts.ts, 86, 9))
     }
     x;
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 90, 13))
+>x : Symbol(x, Decl(ts.ts, 90, 13))
 }
 
 // Repro from #27282
 
 declare const x: (() => void)|null;
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 100, 13))
+>x : Symbol(x, Decl(ts.ts, 100, 13))
 
 declare const ctor: Function;
->ctor : Symbol(ctor, Decl(controlFlowInstanceof.ts, 101, 13))
+>ctor : Symbol(ctor, Decl(ts.ts, 101, 13))
 >Function : Symbol(Function, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
 if (x instanceof ctor) {
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 100, 13))
->ctor : Symbol(ctor, Decl(controlFlowInstanceof.ts, 101, 13))
+>x : Symbol(x, Decl(ts.ts, 100, 13))
+>ctor : Symbol(ctor, Decl(ts.ts, 101, 13))
 
     x();
->x : Symbol(x, Decl(controlFlowInstanceof.ts, 100, 13))
+>x : Symbol(x, Decl(ts.ts, 100, 13))
+}
+
+// Repro from #27550 (based on uglify code)
+=== tests/cases/compiler/uglify.js ===
+/** @constructor */
+function AtTop(val) { this.val = val }
+>AtTop : Symbol(AtTop, Decl(uglify.js, 0, 0))
+>val : Symbol(val, Decl(uglify.js, 1, 15))
+>this.val : Symbol(AtTop.val, Decl(uglify.js, 1, 21))
+>this : Symbol(AtTop, Decl(uglify.js, 0, 0))
+>val : Symbol(AtTop.val, Decl(uglify.js, 1, 21))
+>val : Symbol(val, Decl(uglify.js, 1, 15))
+
+/** @type {*} */
+var v = 1;
+>v : Symbol(v, Decl(uglify.js, 3, 3))
+
+if (v instanceof AtTop) {
+>v : Symbol(v, Decl(uglify.js, 3, 3))
+>AtTop : Symbol(AtTop, Decl(uglify.js, 0, 0))
+
+    v.val
+>v.val : Symbol(AtTop.val, Decl(uglify.js, 1, 21))
+>v : Symbol(v, Decl(uglify.js, 3, 3))
+>val : Symbol(AtTop.val, Decl(uglify.js, 1, 21))
 }
 
diff --git a/tests/baselines/reference/controlFlowInstanceof.types b/tests/baselines/reference/controlFlowInstanceof.types
index e7c05a4c015a4..a4925746620eb 100644
--- a/tests/baselines/reference/controlFlowInstanceof.types
+++ b/tests/baselines/reference/controlFlowInstanceof.types
@@ -1,4 +1,4 @@
-=== tests/cases/compiler/controlFlowInstanceof.ts ===
+=== tests/cases/compiler/ts.ts ===
 // Repros from #10167
 
 function f1(s: Set<string> | Set<number>) {
@@ -261,3 +261,31 @@ if (x instanceof ctor) {
 >x : () => void
 }
 
+// Repro from #27550 (based on uglify code)
+=== tests/cases/compiler/uglify.js ===
+/** @constructor */
+function AtTop(val) { this.val = val }
+>AtTop : typeof AtTop
+>val : any
+>this.val = val : any
+>this.val : any
+>this : AtTop
+>val : any
+>val : any
+
+/** @type {*} */
+var v = 1;
+>v : any
+>1 : 1
+
+if (v instanceof AtTop) {
+>v instanceof AtTop : boolean
+>v : any
+>AtTop : typeof AtTop
+
+    v.val
+>v.val : any
+>v : AtTop
+>val : any
+}
+
diff --git a/tests/cases/compiler/controlFlowInstanceof.ts b/tests/cases/compiler/controlFlowInstanceof.ts
index f9cf844572ff7..6779008d1a62a 100644
--- a/tests/cases/compiler/controlFlowInstanceof.ts
+++ b/tests/cases/compiler/controlFlowInstanceof.ts
@@ -1,6 +1,10 @@
 // @target: es6
+// @noEmit: true
+// @allowJs: true
+// @checkJs: true
 // @strictNullChecks: true
 
+// @Filename: ts.ts
 // Repros from #10167
 
 function f1(s: Set<string> | Set<number>) {
@@ -107,3 +111,13 @@ declare const ctor: Function;
 if (x instanceof ctor) {
     x();
 }
+
+// Repro from #27550 (based on uglify code)
+// @Filename: uglify.js
+/** @constructor */
+function AtTop(val) { this.val = val }
+/** @type {*} */
+var v = 1;
+if (v instanceof AtTop) {
+    v.val
+}

From b65492011d92ddd6552628a72a4c94b1203157b7 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Thu, 4 Oct 2018 09:30:23 -0700
Subject: [PATCH 2/3] Rename test filename

---
 .../reference/controlFlowInstanceof.symbols   | 170 +++++++++---------
 .../reference/controlFlowInstanceof.types     |   2 +-
 tests/cases/compiler/controlFlowInstanceof.ts |   2 +-
 3 files changed, 87 insertions(+), 87 deletions(-)

diff --git a/tests/baselines/reference/controlFlowInstanceof.symbols b/tests/baselines/reference/controlFlowInstanceof.symbols
index df3c552eb2ea9..2be43d5ef6eee 100644
--- a/tests/baselines/reference/controlFlowInstanceof.symbols
+++ b/tests/baselines/reference/controlFlowInstanceof.symbols
@@ -1,250 +1,250 @@
-=== tests/cases/compiler/ts.ts ===
+=== tests/cases/compiler/controlFlowInstanceof.ts ===
 // Repros from #10167
 
 function f1(s: Set<string> | Set<number>) {
->f1 : Symbol(f1, Decl(ts.ts, 0, 0))
->s : Symbol(s, Decl(ts.ts, 2, 12))
+>f1 : Symbol(f1, Decl(controlFlowInstanceof.ts, 0, 0))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s = new Set<number>();
->s : Symbol(s, Decl(ts.ts, 2, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s;  // Set<number>
->s : Symbol(s, Decl(ts.ts, 2, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
 
     if (s instanceof Set) {
->s : Symbol(s, Decl(ts.ts, 2, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
         s;  // Set<number>
->s : Symbol(s, Decl(ts.ts, 2, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
     }
     s;  // Set<number>
->s : Symbol(s, Decl(ts.ts, 2, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
 
     s.add(42);
 >s.add : Symbol(Set.add, Decl(lib.es2015.collection.d.ts, --, --))
->s : Symbol(s, Decl(ts.ts, 2, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 2, 12))
 >add : Symbol(Set.add, Decl(lib.es2015.collection.d.ts, --, --))
 }
 
 function f2(s: Set<string> | Set<number>) {
->f2 : Symbol(f2, Decl(ts.ts, 10, 1))
->s : Symbol(s, Decl(ts.ts, 12, 12))
+>f2 : Symbol(f2, Decl(controlFlowInstanceof.ts, 10, 1))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s = new Set<number>();
->s : Symbol(s, Decl(ts.ts, 12, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s;  // Set<number>
->s : Symbol(s, Decl(ts.ts, 12, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
 
     if (s instanceof Promise) {
->s : Symbol(s, Decl(ts.ts, 12, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
 >Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
         s;  // Set<number> & Promise<any>
->s : Symbol(s, Decl(ts.ts, 12, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
     }
     s;  // Set<number>
->s : Symbol(s, Decl(ts.ts, 12, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
 
     s.add(42);
 >s.add : Symbol(Set.add, Decl(lib.es2015.collection.d.ts, --, --))
->s : Symbol(s, Decl(ts.ts, 12, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 12, 12))
 >add : Symbol(Set.add, Decl(lib.es2015.collection.d.ts, --, --))
 }
 
 function f3(s: Set<string> | Set<number>) {
->f3 : Symbol(f3, Decl(ts.ts, 20, 1))
->s : Symbol(s, Decl(ts.ts, 22, 12))
+>f3 : Symbol(f3, Decl(controlFlowInstanceof.ts, 20, 1))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 22, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s;  // Set<string> | Set<number>
->s : Symbol(s, Decl(ts.ts, 22, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 22, 12))
 
     if (s instanceof Set) {
->s : Symbol(s, Decl(ts.ts, 22, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 22, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
         s;  // Set<string> | Set<number>
->s : Symbol(s, Decl(ts.ts, 22, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 22, 12))
     }
     else {
         s;  // never
->s : Symbol(s, Decl(ts.ts, 22, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 22, 12))
     }
 }
 
 function f4(s: Set<string> | Set<number>) {
->f4 : Symbol(f4, Decl(ts.ts, 30, 1))
->s : Symbol(s, Decl(ts.ts, 32, 12))
+>f4 : Symbol(f4, Decl(controlFlowInstanceof.ts, 30, 1))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s = new Set<number>();
->s : Symbol(s, Decl(ts.ts, 32, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
     s;  // Set<number>
->s : Symbol(s, Decl(ts.ts, 32, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
 
     if (s instanceof Set) {
->s : Symbol(s, Decl(ts.ts, 32, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
 >Set : Symbol(Set, Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.collection.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
         s;  // Set<number>
->s : Symbol(s, Decl(ts.ts, 32, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
     }
     else {
         s;  // never
->s : Symbol(s, Decl(ts.ts, 32, 12))
+>s : Symbol(s, Decl(controlFlowInstanceof.ts, 32, 12))
     }
 }
 
 // More tests
 
 class A { a: string }
->A : Symbol(A, Decl(ts.ts, 41, 1))
->a : Symbol(A.a, Decl(ts.ts, 45, 9))
+>A : Symbol(A, Decl(controlFlowInstanceof.ts, 41, 1))
+>a : Symbol(A.a, Decl(controlFlowInstanceof.ts, 45, 9))
 
 class B extends A { b: string }
->B : Symbol(B, Decl(ts.ts, 45, 21))
->A : Symbol(A, Decl(ts.ts, 41, 1))
->b : Symbol(B.b, Decl(ts.ts, 46, 19))
+>B : Symbol(B, Decl(controlFlowInstanceof.ts, 45, 21))
+>A : Symbol(A, Decl(controlFlowInstanceof.ts, 41, 1))
+>b : Symbol(B.b, Decl(controlFlowInstanceof.ts, 46, 19))
 
 class C extends A { c: string }
->C : Symbol(C, Decl(ts.ts, 46, 31))
->A : Symbol(A, Decl(ts.ts, 41, 1))
->c : Symbol(C.c, Decl(ts.ts, 47, 19))
+>C : Symbol(C, Decl(controlFlowInstanceof.ts, 46, 31))
+>A : Symbol(A, Decl(controlFlowInstanceof.ts, 41, 1))
+>c : Symbol(C.c, Decl(controlFlowInstanceof.ts, 47, 19))
 
 function foo(x: A | undefined) {
->foo : Symbol(foo, Decl(ts.ts, 47, 31))
->x : Symbol(x, Decl(ts.ts, 49, 13))
->A : Symbol(A, Decl(ts.ts, 41, 1))
+>foo : Symbol(foo, Decl(controlFlowInstanceof.ts, 47, 31))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>A : Symbol(A, Decl(controlFlowInstanceof.ts, 41, 1))
 
     x;  // A | undefined
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
 
     if (x instanceof B || x instanceof C) {
->x : Symbol(x, Decl(ts.ts, 49, 13))
->B : Symbol(B, Decl(ts.ts, 45, 21))
->x : Symbol(x, Decl(ts.ts, 49, 13))
->C : Symbol(C, Decl(ts.ts, 46, 31))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>B : Symbol(B, Decl(controlFlowInstanceof.ts, 45, 21))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>C : Symbol(C, Decl(controlFlowInstanceof.ts, 46, 31))
 
         x;  // B | C
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
     }
     x;  // A | undefined
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
 
     if (x instanceof B && x instanceof C) {
->x : Symbol(x, Decl(ts.ts, 49, 13))
->B : Symbol(B, Decl(ts.ts, 45, 21))
->x : Symbol(x, Decl(ts.ts, 49, 13))
->C : Symbol(C, Decl(ts.ts, 46, 31))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>B : Symbol(B, Decl(controlFlowInstanceof.ts, 45, 21))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>C : Symbol(C, Decl(controlFlowInstanceof.ts, 46, 31))
 
         x;  // B & C
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
     }
     x;  // A | undefined
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
 
     if (!x) {
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
 
         return;
     }
     x;  // A
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
 
     if (x instanceof B) {
->x : Symbol(x, Decl(ts.ts, 49, 13))
->B : Symbol(B, Decl(ts.ts, 45, 21))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>B : Symbol(B, Decl(controlFlowInstanceof.ts, 45, 21))
 
         x;  // B
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
 
         if (x instanceof C) {
->x : Symbol(x, Decl(ts.ts, 49, 13))
->C : Symbol(C, Decl(ts.ts, 46, 31))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
+>C : Symbol(C, Decl(controlFlowInstanceof.ts, 46, 31))
 
             x;  // B & C
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
         }
         else {
             x;  // B
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
         }
         x;  // B
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
     }
     else {
         x;  // A
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
     }
     x;  // A
->x : Symbol(x, Decl(ts.ts, 49, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 49, 13))
 }
 
 // X is neither assignable to Y nor a subtype of Y
 // Y is assignable to X, but not a subtype of X
 
 interface X {
->X : Symbol(X, Decl(ts.ts, 77, 1))
+>X : Symbol(X, Decl(controlFlowInstanceof.ts, 77, 1))
 
     x?: string;
->x : Symbol(X.x, Decl(ts.ts, 82, 13))
+>x : Symbol(X.x, Decl(controlFlowInstanceof.ts, 82, 13))
 }
 
 class Y {
->Y : Symbol(Y, Decl(ts.ts, 84, 1))
+>Y : Symbol(Y, Decl(controlFlowInstanceof.ts, 84, 1))
 
     y: string;
->y : Symbol(Y.y, Decl(ts.ts, 86, 9))
+>y : Symbol(Y.y, Decl(controlFlowInstanceof.ts, 86, 9))
 }
 
 function goo(x: X) {
->goo : Symbol(goo, Decl(ts.ts, 88, 1))
->x : Symbol(x, Decl(ts.ts, 90, 13))
->X : Symbol(X, Decl(ts.ts, 77, 1))
+>goo : Symbol(goo, Decl(controlFlowInstanceof.ts, 88, 1))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 90, 13))
+>X : Symbol(X, Decl(controlFlowInstanceof.ts, 77, 1))
 
     x;
->x : Symbol(x, Decl(ts.ts, 90, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 90, 13))
 
     if (x instanceof Y) {
->x : Symbol(x, Decl(ts.ts, 90, 13))
->Y : Symbol(Y, Decl(ts.ts, 84, 1))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 90, 13))
+>Y : Symbol(Y, Decl(controlFlowInstanceof.ts, 84, 1))
 
         x.y;
->x.y : Symbol(Y.y, Decl(ts.ts, 86, 9))
->x : Symbol(x, Decl(ts.ts, 90, 13))
->y : Symbol(Y.y, Decl(ts.ts, 86, 9))
+>x.y : Symbol(Y.y, Decl(controlFlowInstanceof.ts, 86, 9))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 90, 13))
+>y : Symbol(Y.y, Decl(controlFlowInstanceof.ts, 86, 9))
     }
     x;
->x : Symbol(x, Decl(ts.ts, 90, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 90, 13))
 }
 
 // Repro from #27282
 
 declare const x: (() => void)|null;
->x : Symbol(x, Decl(ts.ts, 100, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 100, 13))
 
 declare const ctor: Function;
->ctor : Symbol(ctor, Decl(ts.ts, 101, 13))
+>ctor : Symbol(ctor, Decl(controlFlowInstanceof.ts, 101, 13))
 >Function : Symbol(Function, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --))
 
 if (x instanceof ctor) {
->x : Symbol(x, Decl(ts.ts, 100, 13))
->ctor : Symbol(ctor, Decl(ts.ts, 101, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 100, 13))
+>ctor : Symbol(ctor, Decl(controlFlowInstanceof.ts, 101, 13))
 
     x();
->x : Symbol(x, Decl(ts.ts, 100, 13))
+>x : Symbol(x, Decl(controlFlowInstanceof.ts, 100, 13))
 }
 
 // Repro from #27550 (based on uglify code)
diff --git a/tests/baselines/reference/controlFlowInstanceof.types b/tests/baselines/reference/controlFlowInstanceof.types
index a4925746620eb..9aa38025a1cab 100644
--- a/tests/baselines/reference/controlFlowInstanceof.types
+++ b/tests/baselines/reference/controlFlowInstanceof.types
@@ -1,4 +1,4 @@
-=== tests/cases/compiler/ts.ts ===
+=== tests/cases/compiler/controlFlowInstanceof.ts ===
 // Repros from #10167
 
 function f1(s: Set<string> | Set<number>) {
diff --git a/tests/cases/compiler/controlFlowInstanceof.ts b/tests/cases/compiler/controlFlowInstanceof.ts
index 6779008d1a62a..b032fb708dc58 100644
--- a/tests/cases/compiler/controlFlowInstanceof.ts
+++ b/tests/cases/compiler/controlFlowInstanceof.ts
@@ -4,7 +4,7 @@
 // @checkJs: true
 // @strictNullChecks: true
 
-// @Filename: ts.ts
+// @Filename: controlFlowInstanceof.ts
 // Repros from #10167
 
 function f1(s: Set<string> | Set<number>) {

From 055405b32e49305c980bac9b65cbbb8d9c6ecbea Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Thu, 4 Oct 2018 12:56:07 -0700
Subject: [PATCH 3/3] Fix whitespace lint

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 160570c424759..2b1d7648d85ef 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -15392,7 +15392,7 @@ namespace ts {
 
                 if (!targetType) {
                     let constructSignatures = getSignaturesOfType(rightType, SignatureKind.Construct);
-                    if(constructSignatures.length === 0) {
+                    if (constructSignatures.length === 0) {
                         constructSignatures = filter(getSignaturesOfType(rightType, SignatureKind.Call), sig => isJSConstructor(sig.declaration));
                     }
                     targetType = constructSignatures.length ?