From 3b1309d53f21e7793b708e5fc74fcf997ee92d1c Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Wed, 21 Dec 2016 14:58:44 -0800
Subject: [PATCH] Test parameter initialisation narrowing rules

---
 ...ameterAddsUndefinedWithStrictNullChecks.js | 37 ++++++++++++++-
 ...rAddsUndefinedWithStrictNullChecks.symbols | 36 ++++++++++++++-
 ...terAddsUndefinedWithStrictNullChecks.types | 45 ++++++++++++++++++-
 ...ameterAddsUndefinedWithStrictNullChecks.ts | 17 ++++++-
 4 files changed, 130 insertions(+), 5 deletions(-)

diff --git a/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.js b/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.js
index 3e758907380..50779650c3a 100644
--- a/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.js
+++ b/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.js
@@ -20,12 +20,27 @@ function foo3(x = "string", b: number) {
     x.length; // ok, should be narrowed to string
 }
 
+// .d.ts should have `T | undefined` for foo1, foo2, foo3
 foo1(undefined, 1);
 foo2(undefined, 1);
 foo3(undefined, 1);
 
 
-// .d.ts should have `T | undefined` for foo1, foo2, foo3
+function removeUndefinedButNotFalse(x = true) {
+    if (x === false) {
+        return x;
+    }
+}
+
+declare const cond: boolean;
+function removeNothing(y = cond ? true : undefined) {
+    if (y !== undefined) {
+        if (y === false) {
+            return y;
+        }
+    }
+    return true;
+}
 
 
 //// [defaultParameterAddsUndefinedWithStrictNullChecks.js]
@@ -51,10 +66,25 @@ function foo3(x, b) {
     if (x === void 0) { x = "string"; }
     x.length; // ok, should be narrowed to string
 }
+// .d.ts should have `T | undefined` for foo1, foo2, foo3
 foo1(undefined, 1);
 foo2(undefined, 1);
 foo3(undefined, 1);
-// .d.ts should have `T | undefined` for foo1, foo2, foo3
+function removeUndefinedButNotFalse(x) {
+    if (x === void 0) { x = true; }
+    if (x === false) {
+        return x;
+    }
+}
+function removeNothing(y) {
+    if (y === void 0) { y = cond ? true : undefined; }
+    if (y !== undefined) {
+        if (y === false) {
+            return y;
+        }
+    }
+    return true;
+}
 
 
 //// [defaultParameterAddsUndefinedWithStrictNullChecks.d.ts]
@@ -64,3 +94,6 @@ declare let total: number;
 declare function foo1(x: string | undefined, b: number): void;
 declare function foo2(x: string | undefined, b: number): void;
 declare function foo3(x: string | undefined, b: number): void;
+declare function removeUndefinedButNotFalse(x?: boolean | undefined): false | undefined;
+declare const cond: boolean;
+declare function removeNothing(y?: boolean | undefined): boolean;
diff --git a/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.symbols b/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.symbols
index 97cccafe103..f722ed3af26 100644
--- a/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.symbols
+++ b/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.symbols
@@ -68,6 +68,7 @@ function foo3(x = "string", b: number) {
 >length : Symbol(String.length, Decl(lib.d.ts, --, --))
 }
 
+// .d.ts should have `T | undefined` for foo1, foo2, foo3
 foo1(undefined, 1);
 >foo1 : Symbol(foo1, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 7, 36))
 >undefined : Symbol(undefined)
@@ -81,5 +82,38 @@ foo3(undefined, 1);
 >undefined : Symbol(undefined)
 
 
-// .d.ts should have `T | undefined` for foo1, foo2, foo3
+function removeUndefinedButNotFalse(x = true) {
+>removeUndefinedButNotFalse : Symbol(removeUndefinedButNotFalse, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 24, 19))
+>x : Symbol(x, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 27, 36))
+
+    if (x === false) {
+>x : Symbol(x, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 27, 36))
+
+        return x;
+>x : Symbol(x, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 27, 36))
+    }
+}
+
+declare const cond: boolean;
+>cond : Symbol(cond, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 33, 13))
+
+function removeNothing(y = cond ? true : undefined) {
+>removeNothing : Symbol(removeNothing, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 33, 28))
+>y : Symbol(y, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 34, 23))
+>cond : Symbol(cond, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 33, 13))
+>undefined : Symbol(undefined)
+
+    if (y !== undefined) {
+>y : Symbol(y, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 34, 23))
+>undefined : Symbol(undefined)
+
+        if (y === false) {
+>y : Symbol(y, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 34, 23))
+
+            return y;
+>y : Symbol(y, Decl(defaultParameterAddsUndefinedWithStrictNullChecks.ts, 34, 23))
+        }
+    }
+    return true;
+}
 
diff --git a/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.types b/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.types
index fa41973233e..15535eb435e 100644
--- a/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.types
+++ b/tests/baselines/reference/defaultParameterAddsUndefinedWithStrictNullChecks.types
@@ -96,6 +96,7 @@ function foo3(x = "string", b: number) {
 >length : number
 }
 
+// .d.ts should have `T | undefined` for foo1, foo2, foo3
 foo1(undefined, 1);
 >foo1(undefined, 1) : void
 >foo1 : (x: string | undefined, b: number) => void
@@ -115,5 +116,47 @@ foo3(undefined, 1);
 >1 : 1
 
 
-// .d.ts should have `T | undefined` for foo1, foo2, foo3
+function removeUndefinedButNotFalse(x = true) {
+>removeUndefinedButNotFalse : (x?: boolean | undefined) => false | undefined
+>x : boolean | undefined
+>true : true
+
+    if (x === false) {
+>x === false : boolean
+>x : boolean
+>false : false
+
+        return x;
+>x : false
+    }
+}
+
+declare const cond: boolean;
+>cond : boolean
+
+function removeNothing(y = cond ? true : undefined) {
+>removeNothing : (y?: boolean | undefined) => boolean
+>y : boolean | undefined
+>cond ? true : undefined : true | undefined
+>cond : boolean
+>true : true
+>undefined : undefined
+
+    if (y !== undefined) {
+>y !== undefined : boolean
+>y : boolean | undefined
+>undefined : undefined
+
+        if (y === false) {
+>y === false : boolean
+>y : boolean
+>false : false
+
+            return y;
+>y : false
+        }
+    }
+    return true;
+>true : true
+}
 
diff --git a/tests/cases/compiler/defaultParameterAddsUndefinedWithStrictNullChecks.ts b/tests/cases/compiler/defaultParameterAddsUndefinedWithStrictNullChecks.ts
index 01eefa7dd13..44f17c949e0 100644
--- a/tests/cases/compiler/defaultParameterAddsUndefinedWithStrictNullChecks.ts
+++ b/tests/cases/compiler/defaultParameterAddsUndefinedWithStrictNullChecks.ts
@@ -21,9 +21,24 @@ function foo3(x = "string", b: number) {
     x.length; // ok, should be narrowed to string
 }
 
+// .d.ts should have `T | undefined` for foo1, foo2, foo3
 foo1(undefined, 1);
 foo2(undefined, 1);
 foo3(undefined, 1);
 
 
-// .d.ts should have `T | undefined` for foo1, foo2, foo3
+function removeUndefinedButNotFalse(x = true) {
+    if (x === false) {
+        return x;
+    }
+}
+
+declare const cond: boolean;
+function removeNothing(y = cond ? true : undefined) {
+    if (y !== undefined) {
+        if (y === false) {
+            return y;
+        }
+    }
+    return true;
+}