From 0e1be3efa1ac49e72df9f488e6786273003cccc9 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Fri, 18 Nov 2016 14:13:56 -0800
Subject: [PATCH] Always enable evolving types in Javascript files

---
 src/compiler/checker.ts                       |   4 +-
 .../reference/controlFlowJavascript.js        | 203 ++++++++++++++
 .../reference/controlFlowJavascript.symbols   | 216 +++++++++++++++
 .../reference/controlFlowJavascript.types     | 252 ++++++++++++++++++
 tests/cases/compiler/controlFlowJavascript.ts | 107 ++++++++
 5 files changed, 780 insertions(+), 2 deletions(-)
 create mode 100644 tests/baselines/reference/controlFlowJavascript.js
 create mode 100644 tests/baselines/reference/controlFlowJavascript.symbols
 create mode 100644 tests/baselines/reference/controlFlowJavascript.types
 create mode 100644 tests/cases/compiler/controlFlowJavascript.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 348b287f4f3..f09d622d742 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3239,10 +3239,10 @@ namespace ts {
                 return addOptionality(getTypeFromTypeNode(declaration.type), /*optional*/ declaration.questionToken && includeOptionality);
             }
 
-            if (compilerOptions.noImplicitAny &&
+            if ((compilerOptions.noImplicitAny || declaration.flags & NodeFlags.JavaScriptFile) &&
                 declaration.kind === SyntaxKind.VariableDeclaration && !isBindingPattern(declaration.name) &&
                 !(getCombinedModifierFlags(declaration) & ModifierFlags.Export) && !isInAmbientContext(declaration)) {
-                // If --noImplicitAny is on,
+                // If --noImplicitAny is on or the declaration is in a Javascript file,
                 // use control flow tracked 'any' type for non-ambient, non-exported var or let variables with no
                 // initializer or a 'null' or 'undefined' initializer.
                 if (!(getCombinedNodeFlags(declaration) & NodeFlags.Const) && (!declaration.initializer || isNullOrUndefined(declaration.initializer))) {
diff --git a/tests/baselines/reference/controlFlowJavascript.js b/tests/baselines/reference/controlFlowJavascript.js
new file mode 100644
index 00000000000..66518a6567a
--- /dev/null
+++ b/tests/baselines/reference/controlFlowJavascript.js
@@ -0,0 +1,203 @@
+//// [controlFlowJavascript.js]
+
+let cond = true;
+
+// CFA for 'let' and no initializer
+function f1() {
+    let x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+}
+
+// CFA for 'let' and 'undefined' initializer
+function f2() {
+    let x = undefined;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+}
+
+// CFA for 'let' and 'null' initializer
+function f3() {
+    let x = null;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | null
+}
+
+// CFA for 'var' with no initializer
+function f5() {
+    var x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+}
+
+// CFA for 'var' with 'undefined' initializer
+function f6() {
+    var x = undefined;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+}
+
+// CFA for 'var' with 'null' initializer
+function f7() {
+    var x = null;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | null
+}
+
+// No CFA for captured outer variables
+function f9() {
+    let x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+    function f() {
+        const z = x;  // any
+    }
+}
+
+// No CFA for captured outer variables
+function f10() {
+    let x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+    const f = () => {
+        const z = x;  // any
+    };
+}
+
+
+//// [out.js]
+var cond = true;
+// CFA for 'let' and no initializer
+function f1() {
+    var x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    var y = x; // string | number | undefined
+}
+// CFA for 'let' and 'undefined' initializer
+function f2() {
+    var x = undefined;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    var y = x; // string | number | undefined
+}
+// CFA for 'let' and 'null' initializer
+function f3() {
+    var x = null;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    var y = x; // string | number | null
+}
+// CFA for 'var' with no initializer
+function f5() {
+    var x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    var y = x; // string | number | undefined
+}
+// CFA for 'var' with 'undefined' initializer
+function f6() {
+    var x = undefined;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    var y = x; // string | number | undefined
+}
+// CFA for 'var' with 'null' initializer
+function f7() {
+    var x = null;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    var y = x; // string | number | null
+}
+// No CFA for captured outer variables
+function f9() {
+    var x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    var y = x; // string | number | undefined
+    function f() {
+        var z = x; // any
+    }
+}
+// No CFA for captured outer variables
+function f10() {
+    var x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    var y = x; // string | number | undefined
+    var f = function () {
+        var z = x; // any
+    };
+}
diff --git a/tests/baselines/reference/controlFlowJavascript.symbols b/tests/baselines/reference/controlFlowJavascript.symbols
new file mode 100644
index 00000000000..b3316de3b4e
--- /dev/null
+++ b/tests/baselines/reference/controlFlowJavascript.symbols
@@ -0,0 +1,216 @@
+=== tests/cases/compiler/controlFlowJavascript.js ===
+
+let cond = true;
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+// CFA for 'let' and no initializer
+function f1() {
+>f1 : Symbol(f1, Decl(controlFlowJavascript.js, 1, 16))
+
+    let x;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 5, 7))
+
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = 1;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 5, 7))
+    }
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = "hello";
+>x : Symbol(x, Decl(controlFlowJavascript.js, 5, 7))
+    }
+    const y = x;  // string | number | undefined
+>y : Symbol(y, Decl(controlFlowJavascript.js, 12, 9))
+>x : Symbol(x, Decl(controlFlowJavascript.js, 5, 7))
+}
+
+// CFA for 'let' and 'undefined' initializer
+function f2() {
+>f2 : Symbol(f2, Decl(controlFlowJavascript.js, 13, 1))
+
+    let x = undefined;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 17, 7))
+>undefined : Symbol(undefined)
+
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = 1;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 17, 7))
+    }
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = "hello";
+>x : Symbol(x, Decl(controlFlowJavascript.js, 17, 7))
+    }
+    const y = x;  // string | number | undefined
+>y : Symbol(y, Decl(controlFlowJavascript.js, 24, 9))
+>x : Symbol(x, Decl(controlFlowJavascript.js, 17, 7))
+}
+
+// CFA for 'let' and 'null' initializer
+function f3() {
+>f3 : Symbol(f3, Decl(controlFlowJavascript.js, 25, 1))
+
+    let x = null;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 29, 7))
+
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = 1;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 29, 7))
+    }
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = "hello";
+>x : Symbol(x, Decl(controlFlowJavascript.js, 29, 7))
+    }
+    const y = x;  // string | number | null
+>y : Symbol(y, Decl(controlFlowJavascript.js, 36, 9))
+>x : Symbol(x, Decl(controlFlowJavascript.js, 29, 7))
+}
+
+// CFA for 'var' with no initializer
+function f5() {
+>f5 : Symbol(f5, Decl(controlFlowJavascript.js, 37, 1))
+
+    var x;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 41, 7))
+
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = 1;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 41, 7))
+    }
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = "hello";
+>x : Symbol(x, Decl(controlFlowJavascript.js, 41, 7))
+    }
+    const y = x;  // string | number | undefined
+>y : Symbol(y, Decl(controlFlowJavascript.js, 48, 9))
+>x : Symbol(x, Decl(controlFlowJavascript.js, 41, 7))
+}
+
+// CFA for 'var' with 'undefined' initializer
+function f6() {
+>f6 : Symbol(f6, Decl(controlFlowJavascript.js, 49, 1))
+
+    var x = undefined;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 53, 7))
+>undefined : Symbol(undefined)
+
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = 1;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 53, 7))
+    }
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = "hello";
+>x : Symbol(x, Decl(controlFlowJavascript.js, 53, 7))
+    }
+    const y = x;  // string | number | undefined
+>y : Symbol(y, Decl(controlFlowJavascript.js, 60, 9))
+>x : Symbol(x, Decl(controlFlowJavascript.js, 53, 7))
+}
+
+// CFA for 'var' with 'null' initializer
+function f7() {
+>f7 : Symbol(f7, Decl(controlFlowJavascript.js, 61, 1))
+
+    var x = null;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 65, 7))
+
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = 1;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 65, 7))
+    }
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = "hello";
+>x : Symbol(x, Decl(controlFlowJavascript.js, 65, 7))
+    }
+    const y = x;  // string | number | null
+>y : Symbol(y, Decl(controlFlowJavascript.js, 72, 9))
+>x : Symbol(x, Decl(controlFlowJavascript.js, 65, 7))
+}
+
+// No CFA for captured outer variables
+function f9() {
+>f9 : Symbol(f9, Decl(controlFlowJavascript.js, 73, 1))
+
+    let x;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 77, 7))
+
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = 1;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 77, 7))
+    }
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = "hello";
+>x : Symbol(x, Decl(controlFlowJavascript.js, 77, 7))
+    }
+    const y = x;  // string | number | undefined
+>y : Symbol(y, Decl(controlFlowJavascript.js, 84, 9))
+>x : Symbol(x, Decl(controlFlowJavascript.js, 77, 7))
+
+    function f() {
+>f : Symbol(f, Decl(controlFlowJavascript.js, 84, 16))
+
+        const z = x;  // any
+>z : Symbol(z, Decl(controlFlowJavascript.js, 86, 13))
+>x : Symbol(x, Decl(controlFlowJavascript.js, 77, 7))
+    }
+}
+
+// No CFA for captured outer variables
+function f10() {
+>f10 : Symbol(f10, Decl(controlFlowJavascript.js, 88, 1))
+
+    let x;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 92, 7))
+
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = 1;
+>x : Symbol(x, Decl(controlFlowJavascript.js, 92, 7))
+    }
+    if (cond) {
+>cond : Symbol(cond, Decl(controlFlowJavascript.js, 1, 3))
+
+        x = "hello";
+>x : Symbol(x, Decl(controlFlowJavascript.js, 92, 7))
+    }
+    const y = x;  // string | number | undefined
+>y : Symbol(y, Decl(controlFlowJavascript.js, 99, 9))
+>x : Symbol(x, Decl(controlFlowJavascript.js, 92, 7))
+
+    const f = () => {
+>f : Symbol(f, Decl(controlFlowJavascript.js, 100, 9))
+
+        const z = x;  // any
+>z : Symbol(z, Decl(controlFlowJavascript.js, 101, 13))
+>x : Symbol(x, Decl(controlFlowJavascript.js, 92, 7))
+
+    };
+}
+
diff --git a/tests/baselines/reference/controlFlowJavascript.types b/tests/baselines/reference/controlFlowJavascript.types
new file mode 100644
index 00000000000..0b88c62cb78
--- /dev/null
+++ b/tests/baselines/reference/controlFlowJavascript.types
@@ -0,0 +1,252 @@
+=== tests/cases/compiler/controlFlowJavascript.js ===
+
+let cond = true;
+>cond : boolean
+>true : true
+
+// CFA for 'let' and no initializer
+function f1() {
+>f1 : () => void
+
+    let x;
+>x : any
+
+    if (cond) {
+>cond : boolean
+
+        x = 1;
+>x = 1 : 1
+>x : any
+>1 : 1
+    }
+    if (cond) {
+>cond : boolean
+
+        x = "hello";
+>x = "hello" : "hello"
+>x : any
+>"hello" : "hello"
+    }
+    const y = x;  // string | number | undefined
+>y : string | number
+>x : string | number
+}
+
+// CFA for 'let' and 'undefined' initializer
+function f2() {
+>f2 : () => void
+
+    let x = undefined;
+>x : any
+>undefined : undefined
+
+    if (cond) {
+>cond : boolean
+
+        x = 1;
+>x = 1 : 1
+>x : any
+>1 : 1
+    }
+    if (cond) {
+>cond : boolean
+
+        x = "hello";
+>x = "hello" : "hello"
+>x : any
+>"hello" : "hello"
+    }
+    const y = x;  // string | number | undefined
+>y : string | number
+>x : string | number
+}
+
+// CFA for 'let' and 'null' initializer
+function f3() {
+>f3 : () => void
+
+    let x = null;
+>x : any
+>null : null
+
+    if (cond) {
+>cond : boolean
+
+        x = 1;
+>x = 1 : 1
+>x : any
+>1 : 1
+    }
+    if (cond) {
+>cond : boolean
+
+        x = "hello";
+>x = "hello" : "hello"
+>x : any
+>"hello" : "hello"
+    }
+    const y = x;  // string | number | null
+>y : string | number
+>x : string | number
+}
+
+// CFA for 'var' with no initializer
+function f5() {
+>f5 : () => void
+
+    var x;
+>x : any
+
+    if (cond) {
+>cond : boolean
+
+        x = 1;
+>x = 1 : 1
+>x : any
+>1 : 1
+    }
+    if (cond) {
+>cond : boolean
+
+        x = "hello";
+>x = "hello" : "hello"
+>x : any
+>"hello" : "hello"
+    }
+    const y = x;  // string | number | undefined
+>y : string | number
+>x : string | number
+}
+
+// CFA for 'var' with 'undefined' initializer
+function f6() {
+>f6 : () => void
+
+    var x = undefined;
+>x : any
+>undefined : undefined
+
+    if (cond) {
+>cond : boolean
+
+        x = 1;
+>x = 1 : 1
+>x : any
+>1 : 1
+    }
+    if (cond) {
+>cond : boolean
+
+        x = "hello";
+>x = "hello" : "hello"
+>x : any
+>"hello" : "hello"
+    }
+    const y = x;  // string | number | undefined
+>y : string | number
+>x : string | number
+}
+
+// CFA for 'var' with 'null' initializer
+function f7() {
+>f7 : () => void
+
+    var x = null;
+>x : any
+>null : null
+
+    if (cond) {
+>cond : boolean
+
+        x = 1;
+>x = 1 : 1
+>x : any
+>1 : 1
+    }
+    if (cond) {
+>cond : boolean
+
+        x = "hello";
+>x = "hello" : "hello"
+>x : any
+>"hello" : "hello"
+    }
+    const y = x;  // string | number | null
+>y : string | number
+>x : string | number
+}
+
+// No CFA for captured outer variables
+function f9() {
+>f9 : () => void
+
+    let x;
+>x : any
+
+    if (cond) {
+>cond : boolean
+
+        x = 1;
+>x = 1 : 1
+>x : any
+>1 : 1
+    }
+    if (cond) {
+>cond : boolean
+
+        x = "hello";
+>x = "hello" : "hello"
+>x : any
+>"hello" : "hello"
+    }
+    const y = x;  // string | number | undefined
+>y : string | number
+>x : string | number
+
+    function f() {
+>f : () => void
+
+        const z = x;  // any
+>z : any
+>x : any
+    }
+}
+
+// No CFA for captured outer variables
+function f10() {
+>f10 : () => void
+
+    let x;
+>x : any
+
+    if (cond) {
+>cond : boolean
+
+        x = 1;
+>x = 1 : 1
+>x : any
+>1 : 1
+    }
+    if (cond) {
+>cond : boolean
+
+        x = "hello";
+>x = "hello" : "hello"
+>x : any
+>"hello" : "hello"
+    }
+    const y = x;  // string | number | undefined
+>y : string | number
+>x : string | number
+
+    const f = () => {
+>f : () => void
+>() => {        const z = x;  // any    } : () => void
+
+        const z = x;  // any
+>z : any
+>x : any
+
+    };
+}
+
diff --git a/tests/cases/compiler/controlFlowJavascript.ts b/tests/cases/compiler/controlFlowJavascript.ts
new file mode 100644
index 00000000000..b2886a2233a
--- /dev/null
+++ b/tests/cases/compiler/controlFlowJavascript.ts
@@ -0,0 +1,107 @@
+// @allowJs: true
+// @Filename: controlFlowJavascript.js
+// @out: out.js
+
+let cond = true;
+
+// CFA for 'let' and no initializer
+function f1() {
+    let x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+}
+
+// CFA for 'let' and 'undefined' initializer
+function f2() {
+    let x = undefined;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+}
+
+// CFA for 'let' and 'null' initializer
+function f3() {
+    let x = null;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | null
+}
+
+// CFA for 'var' with no initializer
+function f5() {
+    var x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+}
+
+// CFA for 'var' with 'undefined' initializer
+function f6() {
+    var x = undefined;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+}
+
+// CFA for 'var' with 'null' initializer
+function f7() {
+    var x = null;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | null
+}
+
+// No CFA for captured outer variables
+function f9() {
+    let x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+    function f() {
+        const z = x;  // any
+    }
+}
+
+// No CFA for captured outer variables
+function f10() {
+    let x;
+    if (cond) {
+        x = 1;
+    }
+    if (cond) {
+        x = "hello";
+    }
+    const y = x;  // string | number | undefined
+    const f = () => {
+        const z = x;  // any
+    };
+}