From c9ac15ae56ff55dd6b8ae4bd00c929ecf489f2ec Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Mon, 26 Mar 2018 13:42:34 -0700
Subject: [PATCH] In JS, this assignments in constructors are preferred and
 nullable initializers become any (#22882)

* First draft:in js, constructor declaration is preferred

* Add tests

* initializer of null|undefined gives any in JS

Also move this-assignment fixes out of binder. I'm going to put it in
the checker instead.

* In JS, initializer null|undefined: any, []: any[]

* First draft of js prefer-ctor-types overhaul

* Update tests, update baselines

* Improve readability of constructor-type preference

* Cleanup: Remove TODO and duplication

* Add noImplicitAny errors

* Add comment
---
 src/compiler/checker.ts                       |  59 ++++-
 ...ringClassMembersFromAssignments.errors.txt | 148 +++++++++++
 .../inferringClassMembersFromAssignments.js   |  22 +-
 ...ferringClassMembersFromAssignments.symbols | 202 +++++++++------
 ...inferringClassMembersFromAssignments.types |  69 ++++-
 .../typeFromJSConstructor.errors.txt          |  52 ++++
 .../reference/typeFromJSConstructor.symbols   | 111 ++++++++
 .../reference/typeFromJSConstructor.types     | 165 ++++++++++++
 .../typeFromJSInitializer.errors.txt          |  75 ++++++
 .../reference/typeFromJSInitializer.symbols   | 171 +++++++++++++
 .../reference/typeFromJSInitializer.types     | 241 ++++++++++++++++++
 .../typeFromPropertyAssignment22.errors.txt   |  10 +-
 .../typeFromPropertyAssignment22.symbols      |   2 +-
 .../typeFromPropertyAssignment22.types        |  24 +-
 .../inferringClassMembersFromAssignments.ts   |  13 +-
 .../salsa/typeFromJSConstructor.ts            |  36 +++
 .../salsa/typeFromJSInitializer.ts            |  59 +++++
 .../salsa/typeFromPropertyAssignment22.ts     |   2 +-
 18 files changed, 1340 insertions(+), 121 deletions(-)
 create mode 100644 tests/baselines/reference/inferringClassMembersFromAssignments.errors.txt
 create mode 100644 tests/baselines/reference/typeFromJSConstructor.errors.txt
 create mode 100644 tests/baselines/reference/typeFromJSConstructor.symbols
 create mode 100644 tests/baselines/reference/typeFromJSConstructor.types
 create mode 100644 tests/baselines/reference/typeFromJSInitializer.errors.txt
 create mode 100644 tests/baselines/reference/typeFromJSInitializer.symbols
 create mode 100644 tests/baselines/reference/typeFromJSInitializer.types
 create mode 100644 tests/cases/conformance/salsa/typeFromJSConstructor.ts
 create mode 100644 tests/cases/conformance/salsa/typeFromJSInitializer.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 35204060c32..e56447b85ac 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4255,10 +4255,12 @@ namespace ts {
                 return getWidenedLiteralType(checkExpressionCached(specialDeclaration));
             }
             const types: Type[] = [];
+            let constructorTypes: Type[];
             let definedInConstructor = false;
             let definedInMethod = false;
             let jsDocType: Type;
             for (const declaration of symbol.declarations) {
+                let declarationInConstructor = false;
                 const expression = declaration.kind === SyntaxKind.BinaryExpression ? <BinaryExpression>declaration :
                     declaration.kind === SyntaxKind.PropertyAccessExpression ? <BinaryExpression>getAncestor(declaration, SyntaxKind.BinaryExpression) :
                         undefined;
@@ -4271,9 +4273,10 @@ namespace ts {
                     const thisContainer = getThisContainer(expression, /*includeArrowFunctions*/ false);
                     // Properties defined in a constructor (or javascript constructor function) don't get undefined added.
                     // Function expressions that are assigned to the prototype count as methods.
-                    if (thisContainer.kind === SyntaxKind.Constructor ||
+                    declarationInConstructor = thisContainer.kind === SyntaxKind.Constructor ||
                         thisContainer.kind === SyntaxKind.FunctionDeclaration ||
-                        (thisContainer.kind === SyntaxKind.FunctionExpression && !isPrototypePropertyAssignment(thisContainer.parent))) {
+                        (thisContainer.kind === SyntaxKind.FunctionExpression && !isPrototypePropertyAssignment(thisContainer.parent));
+                    if (declarationInConstructor) {
                         definedInConstructor = true;
                     }
                     else {
@@ -4296,14 +4299,37 @@ namespace ts {
                 }
                 else if (!jsDocType) {
                     // If we don't have an explicit JSDoc type, get the type from the expression.
-                    types.push(getWidenedLiteralType(checkExpressionCached(expression.right)));
+                    const type = getWidenedLiteralType(checkExpressionCached(expression.right));
+                    let anyedType = type;
+                    if (isEmptyArrayLiteralType(type)) {
+                        anyedType = anyArrayType;
+                        if (noImplicitAny) {
+                            reportImplicitAnyError(expression, anyArrayType);
+                        }
+                    }
+                    types.push(anyedType);
+                    if (declarationInConstructor) {
+                        (constructorTypes || (constructorTypes = [])).push(anyedType);
+                    }
                 }
             }
-
-            const type = jsDocType || getUnionType(types, UnionReduction.Subtype);
-            return getWidenedType(addOptionality(type, definedInMethod && !definedInConstructor));
+            let type = jsDocType;
+            if (!type) {
+                // use only the constructor types unless only null | undefined (including widening variants) were assigned there
+                const sourceTypes = some(constructorTypes, t => !!(t.flags & ~(TypeFlags.Nullable | TypeFlags.ContainsWideningType))) ? constructorTypes : types;
+                type = getUnionType(sourceTypes, UnionReduction.Subtype);
+            }
+            const widened = getWidenedType(addOptionality(type, definedInMethod && !definedInConstructor));
+            if (filterType(widened, t => !!(t.flags & ~TypeFlags.Nullable)) === neverType) {
+                if (noImplicitAny) {
+                    reportImplicitAnyError(symbol.valueDeclaration, anyType);
+                }
+                return anyType;
+            }
+            return widened;
         }
 
+
         // Return the type implied by a binding pattern element. This is the type of the initializer of the element if
         // one is present. Otherwise, if the element is itself a binding pattern, it is the type implied by the binding
         // pattern. Otherwise, it is the type any.
@@ -11394,6 +11420,7 @@ namespace ts {
             const typeAsString = typeToString(getWidenedType(type));
             let diagnostic: DiagnosticMessage;
             switch (declaration.kind) {
+                case SyntaxKind.BinaryExpression:
                 case SyntaxKind.PropertyDeclaration:
                 case SyntaxKind.PropertySignature:
                     diagnostic = Diagnostics.Member_0_implicitly_has_an_1_type;
@@ -19689,11 +19716,27 @@ namespace ts {
         }
 
         function checkDeclarationInitializer(declaration: HasExpressionInitializer) {
-            const initializer = isInJavaScriptFile(declaration) && getDeclaredJavascriptInitializer(declaration) || declaration.initializer;
+            const inJs = isInJavaScriptFile(declaration);
+            const initializer = inJs && getDeclaredJavascriptInitializer(declaration) || declaration.initializer;
             const type = getTypeOfExpression(initializer, /*cache*/ true);
-            return getCombinedNodeFlags(declaration) & NodeFlags.Const ||
+            const widened = getCombinedNodeFlags(declaration) & NodeFlags.Const ||
                 (getCombinedModifierFlags(declaration) & ModifierFlags.Readonly && !isParameterPropertyDeclaration(declaration)) ||
                 isTypeAssertion(initializer) ? type : getWidenedLiteralType(type);
+            if (inJs) {
+                if (widened.flags & TypeFlags.Nullable) {
+                    if (noImplicitAny) {
+                        reportImplicitAnyError(declaration, anyType);
+                    }
+                    return anyType;
+                }
+                else if (isEmptyArrayLiteralType(widened)) {
+                    if (noImplicitAny) {
+                        reportImplicitAnyError(declaration, anyArrayType);
+                    }
+                    return anyArrayType;
+                }
+            }
+            return widened;
         }
 
         function isLiteralOfContextualType(candidateType: Type, contextualType: Type): boolean {
diff --git a/tests/baselines/reference/inferringClassMembersFromAssignments.errors.txt b/tests/baselines/reference/inferringClassMembersFromAssignments.errors.txt
new file mode 100644
index 00000000000..48fa2cdb9d3
--- /dev/null
+++ b/tests/baselines/reference/inferringClassMembersFromAssignments.errors.txt
@@ -0,0 +1,148 @@
+tests/cases/conformance/salsa/a.js(14,13): error TS7008: Member 'inMethodNullable' implicitly has an 'any' type.
+tests/cases/conformance/salsa/a.js(20,9): error TS2322: Type '"string"' is not assignable to type 'number'.
+tests/cases/conformance/salsa/a.js(39,9): error TS2322: Type 'false' is not assignable to type 'number'.
+tests/cases/conformance/salsa/a.js(93,13): error TS2334: 'this' cannot be referenced in a static property initializer.
+tests/cases/conformance/salsa/a.js(96,13): error TS2334: 'this' cannot be referenced in a static property initializer.
+
+
+==== tests/cases/conformance/salsa/a.js (5 errors) ====
+    class C {
+        constructor() {
+            if (Math.random()) {
+                this.inConstructor = 0;
+            }
+            else {
+                this.inConstructor = "string"
+            }
+            this.inMultiple = 0;
+        }
+        method() {
+            if (Math.random()) {
+                this.inMethod = 0;
+                this.inMethodNullable = null;
+                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS7008: Member 'inMethodNullable' implicitly has an 'any' type.
+            }
+            else {
+                this.inMethod = "string"
+                this.inMethodNullable = undefined;
+            }
+            this.inMultiple = "string";
+            ~~~~~~~~~~~~~~~
+!!! error TS2322: Type '"string"' is not assignable to type 'number'.
+            this.inMultipleMethods = "string";
+    
+            var action = () => {
+                if (Math.random()) {
+                    this.inNestedArrowFunction = 0;
+                }
+                else {
+                    this.inNestedArrowFunction = "string"
+                }
+            };
+        }
+        get() {
+            if (Math.random()) {
+                this.inGetter = 0;
+            }
+            else {
+                this.inGetter = "string"
+            }
+            this.inMultiple = false;
+            ~~~~~~~~~~~~~~~
+!!! error TS2322: Type 'false' is not assignable to type 'number'.
+            this.inMultipleMethods = false;
+        }
+        set() {
+            if (Math.random()) {
+                this.inSetter = 0;
+            }
+            else {
+                this.inSetter = "string"
+            }
+        }
+        prop = () => {
+            if (Math.random()) {
+                this.inPropertyDeclaration = 0;
+            }
+            else {
+                this.inPropertyDeclaration = "string"
+            }
+        }
+        static method() {
+            if (Math.random()) {
+                this.inStaticMethod = 0;
+            }
+            else {
+                this.inStaticMethod = "string"
+            }
+    
+            var action = () => {
+                if (Math.random()) {
+                    this.inStaticNestedArrowFunction = 0;
+                }
+                else {
+                    this.inStaticNestedArrowFunction = "string"
+                }
+            };
+        }
+        static get() {
+            if (Math.random()) {
+                this.inStaticGetter = 0;
+            }
+            else {
+                this.inStaticGetter = "string"
+            }
+        }
+        static set() {
+            if (Math.random()) {
+                this.inStaticSetter = 0;
+            }
+            else {
+                this.inStaticSetter = "string"
+            }
+        }
+        static prop = () => {
+            if (Math.random()) {
+                this.inStaticPropertyDeclaration = 0;
+                ~~~~
+!!! error TS2334: 'this' cannot be referenced in a static property initializer.
+            }
+            else {
+                this.inStaticPropertyDeclaration = "string"
+                ~~~~
+!!! error TS2334: 'this' cannot be referenced in a static property initializer.
+            }
+        }
+    }
+    
+==== tests/cases/conformance/salsa/b.ts (0 errors) ====
+    var c = new C();
+    
+    var stringOrNumber: string | number;
+    var stringOrNumber = c.inConstructor;
+    
+    var stringOrNumberOrUndefined: string | number | undefined;
+    
+    var stringOrNumberOrUndefined = c.inMethod;
+    var stringOrNumberOrUndefined = c.inGetter;
+    var stringOrNumberOrUndefined = c.inSetter;
+    var stringOrNumberOrUndefined = c.inPropertyDeclaration;
+    var stringOrNumberOrUndefined = c.inNestedArrowFunction
+    
+    var stringOrNumberOrBoolean: string | number | boolean;
+    
+    var number: number;
+    var number = c.inMultiple;
+    var stringOrBooleanOrUndefined : string | boolean | undefined;
+    var stringOrBooleanOrUndefined = c.inMultipleMethods;
+    var any: any;
+    var any = c.inMethodNullable;
+    
+    
+    var stringOrNumberOrUndefined = C.inStaticMethod;
+    var stringOrNumberOrUndefined = C.inStaticGetter;
+    var stringOrNumberOrUndefined = C.inStaticSetter;
+    var stringOrNumberOrUndefined = C.inStaticPropertyDeclaration;
+    var stringOrNumberOrUndefined = C.inStaticNestedArrowFunction;
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/inferringClassMembersFromAssignments.js b/tests/baselines/reference/inferringClassMembersFromAssignments.js
index 90f87734b2e..e8d25a917dd 100644
--- a/tests/baselines/reference/inferringClassMembersFromAssignments.js
+++ b/tests/baselines/reference/inferringClassMembersFromAssignments.js
@@ -14,11 +14,14 @@ class C {
     method() {
         if (Math.random()) {
             this.inMethod = 0;
+            this.inMethodNullable = null;
         }
         else {
             this.inMethod = "string"
+            this.inMethodNullable = undefined;
         }
         this.inMultiple = "string";
+        this.inMultipleMethods = "string";
 
         var action = () => {
             if (Math.random()) {
@@ -37,6 +40,7 @@ class C {
             this.inGetter = "string"
         }
         this.inMultiple = false;
+        this.inMultipleMethods = false;
     }
     set() {
         if (Math.random()) {
@@ -113,7 +117,12 @@ var stringOrNumberOrUndefined = c.inNestedArrowFunction
 
 var stringOrNumberOrBoolean: string | number | boolean;
 
-var stringOrNumberOrBoolean = c.inMultiple;
+var number: number;
+var number = c.inMultiple;
+var stringOrBooleanOrUndefined : string | boolean | undefined;
+var stringOrBooleanOrUndefined = c.inMultipleMethods;
+var any: any;
+var any = c.inMethodNullable;
 
 
 var stringOrNumberOrUndefined = C.inStaticMethod;
@@ -148,11 +157,14 @@ var C = /** @class */ (function () {
         var _this = this;
         if (Math.random()) {
             this.inMethod = 0;
+            this.inMethodNullable = null;
         }
         else {
             this.inMethod = "string";
+            this.inMethodNullable = undefined;
         }
         this.inMultiple = "string";
+        this.inMultipleMethods = "string";
         var action = function () {
             if (Math.random()) {
                 _this.inNestedArrowFunction = 0;
@@ -170,6 +182,7 @@ var C = /** @class */ (function () {
             this.inGetter = "string";
         }
         this.inMultiple = false;
+        this.inMultipleMethods = false;
     };
     C.prototype.set = function () {
         if (Math.random()) {
@@ -232,7 +245,12 @@ var stringOrNumberOrUndefined = c.inSetter;
 var stringOrNumberOrUndefined = c.inPropertyDeclaration;
 var stringOrNumberOrUndefined = c.inNestedArrowFunction;
 var stringOrNumberOrBoolean;
-var stringOrNumberOrBoolean = c.inMultiple;
+var number;
+var number = c.inMultiple;
+var stringOrBooleanOrUndefined;
+var stringOrBooleanOrUndefined = c.inMultipleMethods;
+var any;
+var any = c.inMethodNullable;
 var stringOrNumberOrUndefined = C.inStaticMethod;
 var stringOrNumberOrUndefined = C.inStaticGetter;
 var stringOrNumberOrUndefined = C.inStaticSetter;
diff --git a/tests/baselines/reference/inferringClassMembersFromAssignments.symbols b/tests/baselines/reference/inferringClassMembersFromAssignments.symbols
index a2f18b84a07..316b9f08f7c 100644
--- a/tests/baselines/reference/inferringClassMembersFromAssignments.symbols
+++ b/tests/baselines/reference/inferringClassMembersFromAssignments.symbols
@@ -20,9 +20,9 @@ class C {
 >inConstructor : Symbol(C.inConstructor, Decl(a.js, 2, 28), Decl(a.js, 5, 14))
         }
         this.inMultiple = 0;
->this.inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 16, 9), Decl(a.js, 34, 9))
+>this.inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 18, 9), Decl(a.js, 37, 9))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 16, 9), Decl(a.js, 34, 9))
+>inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 18, 9), Decl(a.js, 37, 9))
     }
     method() {
 >method : Symbol(C.method, Decl(a.js, 9, 5))
@@ -33,23 +33,39 @@ class C {
 >random : Symbol(Math.random, Decl(lib.d.ts, --, --))
 
             this.inMethod = 0;
->this.inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 14))
+>this.inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 15, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 14))
+>inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 15, 14))
+
+            this.inMethodNullable = null;
+>this.inMethodNullable : Symbol(C.inMethodNullable, Decl(a.js, 12, 30), Decl(a.js, 16, 36))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inMethodNullable : Symbol(C.inMethodNullable, Decl(a.js, 12, 30), Decl(a.js, 16, 36))
         }
         else {
             this.inMethod = "string"
->this.inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 14))
+>this.inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 15, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 14))
+>inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 15, 14))
+
+            this.inMethodNullable = undefined;
+>this.inMethodNullable : Symbol(C.inMethodNullable, Decl(a.js, 12, 30), Decl(a.js, 16, 36))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inMethodNullable : Symbol(C.inMethodNullable, Decl(a.js, 12, 30), Decl(a.js, 16, 36))
+>undefined : Symbol(undefined)
         }
         this.inMultiple = "string";
->this.inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 16, 9), Decl(a.js, 34, 9))
+>this.inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 18, 9), Decl(a.js, 37, 9))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 16, 9), Decl(a.js, 34, 9))
+>inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 18, 9), Decl(a.js, 37, 9))
+
+        this.inMultipleMethods = "string";
+>this.inMultipleMethods : Symbol(C.inMultipleMethods, Decl(a.js, 19, 35), Decl(a.js, 38, 32))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inMultipleMethods : Symbol(C.inMultipleMethods, Decl(a.js, 19, 35), Decl(a.js, 38, 32))
 
         var action = () => {
->action : Symbol(action, Decl(a.js, 19, 11))
+>action : Symbol(action, Decl(a.js, 22, 11))
 
             if (Math.random()) {
 >Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
@@ -57,20 +73,20 @@ class C {
 >random : Symbol(Math.random, Decl(lib.d.ts, --, --))
 
                 this.inNestedArrowFunction = 0;
->this.inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 20, 32), Decl(a.js, 23, 18))
+>this.inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 23, 32), Decl(a.js, 26, 18))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 20, 32), Decl(a.js, 23, 18))
+>inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 23, 32), Decl(a.js, 26, 18))
             }
             else {
                 this.inNestedArrowFunction = "string"
->this.inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 20, 32), Decl(a.js, 23, 18))
+>this.inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 23, 32), Decl(a.js, 26, 18))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 20, 32), Decl(a.js, 23, 18))
+>inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 23, 32), Decl(a.js, 26, 18))
             }
         };
     }
     get() {
->get : Symbol(C.get, Decl(a.js, 27, 5))
+>get : Symbol(C.get, Decl(a.js, 30, 5))
 
         if (Math.random()) {
 >Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
@@ -78,23 +94,28 @@ class C {
 >random : Symbol(Math.random, Decl(lib.d.ts, --, --))
 
             this.inGetter = 0;
->this.inGetter : Symbol(C.inGetter, Decl(a.js, 29, 28), Decl(a.js, 32, 14))
+>this.inGetter : Symbol(C.inGetter, Decl(a.js, 32, 28), Decl(a.js, 35, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inGetter : Symbol(C.inGetter, Decl(a.js, 29, 28), Decl(a.js, 32, 14))
+>inGetter : Symbol(C.inGetter, Decl(a.js, 32, 28), Decl(a.js, 35, 14))
         }
         else {
             this.inGetter = "string"
->this.inGetter : Symbol(C.inGetter, Decl(a.js, 29, 28), Decl(a.js, 32, 14))
+>this.inGetter : Symbol(C.inGetter, Decl(a.js, 32, 28), Decl(a.js, 35, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inGetter : Symbol(C.inGetter, Decl(a.js, 29, 28), Decl(a.js, 32, 14))
+>inGetter : Symbol(C.inGetter, Decl(a.js, 32, 28), Decl(a.js, 35, 14))
         }
         this.inMultiple = false;
->this.inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 16, 9), Decl(a.js, 34, 9))
+>this.inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 18, 9), Decl(a.js, 37, 9))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 16, 9), Decl(a.js, 34, 9))
+>inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 18, 9), Decl(a.js, 37, 9))
+
+        this.inMultipleMethods = false;
+>this.inMultipleMethods : Symbol(C.inMultipleMethods, Decl(a.js, 19, 35), Decl(a.js, 38, 32))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inMultipleMethods : Symbol(C.inMultipleMethods, Decl(a.js, 19, 35), Decl(a.js, 38, 32))
     }
     set() {
->set : Symbol(C.set, Decl(a.js, 36, 5))
+>set : Symbol(C.set, Decl(a.js, 40, 5))
 
         if (Math.random()) {
 >Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
@@ -102,19 +123,19 @@ class C {
 >random : Symbol(Math.random, Decl(lib.d.ts, --, --))
 
             this.inSetter = 0;
->this.inSetter : Symbol(C.inSetter, Decl(a.js, 38, 28), Decl(a.js, 41, 14))
+>this.inSetter : Symbol(C.inSetter, Decl(a.js, 42, 28), Decl(a.js, 45, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inSetter : Symbol(C.inSetter, Decl(a.js, 38, 28), Decl(a.js, 41, 14))
+>inSetter : Symbol(C.inSetter, Decl(a.js, 42, 28), Decl(a.js, 45, 14))
         }
         else {
             this.inSetter = "string"
->this.inSetter : Symbol(C.inSetter, Decl(a.js, 38, 28), Decl(a.js, 41, 14))
+>this.inSetter : Symbol(C.inSetter, Decl(a.js, 42, 28), Decl(a.js, 45, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inSetter : Symbol(C.inSetter, Decl(a.js, 38, 28), Decl(a.js, 41, 14))
+>inSetter : Symbol(C.inSetter, Decl(a.js, 42, 28), Decl(a.js, 45, 14))
         }
     }
     prop = () => {
->prop : Symbol(C.prop, Decl(a.js, 44, 5))
+>prop : Symbol(C.prop, Decl(a.js, 48, 5))
 
         if (Math.random()) {
 >Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
@@ -122,19 +143,19 @@ class C {
 >random : Symbol(Math.random, Decl(lib.d.ts, --, --))
 
             this.inPropertyDeclaration = 0;
->this.inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 46, 28), Decl(a.js, 49, 14))
+>this.inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 50, 28), Decl(a.js, 53, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 46, 28), Decl(a.js, 49, 14))
+>inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 50, 28), Decl(a.js, 53, 14))
         }
         else {
             this.inPropertyDeclaration = "string"
->this.inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 46, 28), Decl(a.js, 49, 14))
+>this.inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 50, 28), Decl(a.js, 53, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 46, 28), Decl(a.js, 49, 14))
+>inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 50, 28), Decl(a.js, 53, 14))
         }
     }
     static method() {
->method : Symbol(C.method, Decl(a.js, 52, 5))
+>method : Symbol(C.method, Decl(a.js, 56, 5))
 
         if (Math.random()) {
 >Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
@@ -142,19 +163,19 @@ class C {
 >random : Symbol(Math.random, Decl(lib.d.ts, --, --))
 
             this.inStaticMethod = 0;
->this.inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 54, 28), Decl(a.js, 57, 14))
+>this.inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 58, 28), Decl(a.js, 61, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 54, 28), Decl(a.js, 57, 14))
+>inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 58, 28), Decl(a.js, 61, 14))
         }
         else {
             this.inStaticMethod = "string"
->this.inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 54, 28), Decl(a.js, 57, 14))
+>this.inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 58, 28), Decl(a.js, 61, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 54, 28), Decl(a.js, 57, 14))
+>inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 58, 28), Decl(a.js, 61, 14))
         }
 
         var action = () => {
->action : Symbol(action, Decl(a.js, 61, 11))
+>action : Symbol(action, Decl(a.js, 65, 11))
 
             if (Math.random()) {
 >Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
@@ -162,20 +183,20 @@ class C {
 >random : Symbol(Math.random, Decl(lib.d.ts, --, --))
 
                 this.inStaticNestedArrowFunction = 0;
->this.inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 62, 32), Decl(a.js, 65, 18))
+>this.inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 66, 32), Decl(a.js, 69, 18))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 62, 32), Decl(a.js, 65, 18))
+>inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 66, 32), Decl(a.js, 69, 18))
             }
             else {
                 this.inStaticNestedArrowFunction = "string"
->this.inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 62, 32), Decl(a.js, 65, 18))
+>this.inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 66, 32), Decl(a.js, 69, 18))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 62, 32), Decl(a.js, 65, 18))
+>inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 66, 32), Decl(a.js, 69, 18))
             }
         };
     }
     static get() {
->get : Symbol(C.get, Decl(a.js, 69, 5))
+>get : Symbol(C.get, Decl(a.js, 73, 5))
 
         if (Math.random()) {
 >Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
@@ -183,19 +204,19 @@ class C {
 >random : Symbol(Math.random, Decl(lib.d.ts, --, --))
 
             this.inStaticGetter = 0;
->this.inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 71, 28), Decl(a.js, 74, 14))
+>this.inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 75, 28), Decl(a.js, 78, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 71, 28), Decl(a.js, 74, 14))
+>inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 75, 28), Decl(a.js, 78, 14))
         }
         else {
             this.inStaticGetter = "string"
->this.inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 71, 28), Decl(a.js, 74, 14))
+>this.inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 75, 28), Decl(a.js, 78, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 71, 28), Decl(a.js, 74, 14))
+>inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 75, 28), Decl(a.js, 78, 14))
         }
     }
     static set() {
->set : Symbol(C.set, Decl(a.js, 77, 5))
+>set : Symbol(C.set, Decl(a.js, 81, 5))
 
         if (Math.random()) {
 >Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
@@ -203,19 +224,19 @@ class C {
 >random : Symbol(Math.random, Decl(lib.d.ts, --, --))
 
             this.inStaticSetter = 0;
->this.inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 79, 28), Decl(a.js, 82, 14))
+>this.inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 83, 28), Decl(a.js, 86, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 79, 28), Decl(a.js, 82, 14))
+>inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 83, 28), Decl(a.js, 86, 14))
         }
         else {
             this.inStaticSetter = "string"
->this.inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 79, 28), Decl(a.js, 82, 14))
+>this.inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 83, 28), Decl(a.js, 86, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 79, 28), Decl(a.js, 82, 14))
+>inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 83, 28), Decl(a.js, 86, 14))
         }
     }
     static prop = () => {
->prop : Symbol(C.prop, Decl(a.js, 85, 5))
+>prop : Symbol(C.prop, Decl(a.js, 89, 5))
 
         if (Math.random()) {
 >Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
@@ -223,15 +244,15 @@ class C {
 >random : Symbol(Math.random, Decl(lib.d.ts, --, --))
 
             this.inStaticPropertyDeclaration = 0;
->this.inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 87, 28), Decl(a.js, 90, 14))
+>this.inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 91, 28), Decl(a.js, 94, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 87, 28), Decl(a.js, 90, 14))
+>inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 91, 28), Decl(a.js, 94, 14))
         }
         else {
             this.inStaticPropertyDeclaration = "string"
->this.inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 87, 28), Decl(a.js, 90, 14))
+>this.inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 91, 28), Decl(a.js, 94, 14))
 >this : Symbol(C, Decl(a.js, 0, 0))
->inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 87, 28), Decl(a.js, 90, 14))
+>inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 91, 28), Decl(a.js, 94, 14))
         }
     }
 }
@@ -255,71 +276,92 @@ var stringOrNumberOrUndefined: string | number | undefined;
 
 var stringOrNumberOrUndefined = c.inMethod;
 >stringOrNumberOrUndefined : Symbol(stringOrNumberOrUndefined, Decl(b.ts, 5, 3), Decl(b.ts, 7, 3), Decl(b.ts, 8, 3), Decl(b.ts, 9, 3), Decl(b.ts, 10, 3) ... and 6 more)
->c.inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 14))
+>c.inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 15, 14))
 >c : Symbol(c, Decl(b.ts, 0, 3))
->inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 14))
+>inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 15, 14))
 
 var stringOrNumberOrUndefined = c.inGetter;
 >stringOrNumberOrUndefined : Symbol(stringOrNumberOrUndefined, Decl(b.ts, 5, 3), Decl(b.ts, 7, 3), Decl(b.ts, 8, 3), Decl(b.ts, 9, 3), Decl(b.ts, 10, 3) ... and 6 more)
->c.inGetter : Symbol(C.inGetter, Decl(a.js, 29, 28), Decl(a.js, 32, 14))
+>c.inGetter : Symbol(C.inGetter, Decl(a.js, 32, 28), Decl(a.js, 35, 14))
 >c : Symbol(c, Decl(b.ts, 0, 3))
->inGetter : Symbol(C.inGetter, Decl(a.js, 29, 28), Decl(a.js, 32, 14))
+>inGetter : Symbol(C.inGetter, Decl(a.js, 32, 28), Decl(a.js, 35, 14))
 
 var stringOrNumberOrUndefined = c.inSetter;
 >stringOrNumberOrUndefined : Symbol(stringOrNumberOrUndefined, Decl(b.ts, 5, 3), Decl(b.ts, 7, 3), Decl(b.ts, 8, 3), Decl(b.ts, 9, 3), Decl(b.ts, 10, 3) ... and 6 more)
->c.inSetter : Symbol(C.inSetter, Decl(a.js, 38, 28), Decl(a.js, 41, 14))
+>c.inSetter : Symbol(C.inSetter, Decl(a.js, 42, 28), Decl(a.js, 45, 14))
 >c : Symbol(c, Decl(b.ts, 0, 3))
->inSetter : Symbol(C.inSetter, Decl(a.js, 38, 28), Decl(a.js, 41, 14))
+>inSetter : Symbol(C.inSetter, Decl(a.js, 42, 28), Decl(a.js, 45, 14))
 
 var stringOrNumberOrUndefined = c.inPropertyDeclaration;
 >stringOrNumberOrUndefined : Symbol(stringOrNumberOrUndefined, Decl(b.ts, 5, 3), Decl(b.ts, 7, 3), Decl(b.ts, 8, 3), Decl(b.ts, 9, 3), Decl(b.ts, 10, 3) ... and 6 more)
->c.inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 46, 28), Decl(a.js, 49, 14))
+>c.inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 50, 28), Decl(a.js, 53, 14))
 >c : Symbol(c, Decl(b.ts, 0, 3))
->inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 46, 28), Decl(a.js, 49, 14))
+>inPropertyDeclaration : Symbol(C.inPropertyDeclaration, Decl(a.js, 50, 28), Decl(a.js, 53, 14))
 
 var stringOrNumberOrUndefined = c.inNestedArrowFunction
 >stringOrNumberOrUndefined : Symbol(stringOrNumberOrUndefined, Decl(b.ts, 5, 3), Decl(b.ts, 7, 3), Decl(b.ts, 8, 3), Decl(b.ts, 9, 3), Decl(b.ts, 10, 3) ... and 6 more)
->c.inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 20, 32), Decl(a.js, 23, 18))
+>c.inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 23, 32), Decl(a.js, 26, 18))
 >c : Symbol(c, Decl(b.ts, 0, 3))
->inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 20, 32), Decl(a.js, 23, 18))
+>inNestedArrowFunction : Symbol(C.inNestedArrowFunction, Decl(a.js, 23, 32), Decl(a.js, 26, 18))
 
 var stringOrNumberOrBoolean: string | number | boolean;
->stringOrNumberOrBoolean : Symbol(stringOrNumberOrBoolean, Decl(b.ts, 13, 3), Decl(b.ts, 15, 3))
+>stringOrNumberOrBoolean : Symbol(stringOrNumberOrBoolean, Decl(b.ts, 13, 3))
 
-var stringOrNumberOrBoolean = c.inMultiple;
->stringOrNumberOrBoolean : Symbol(stringOrNumberOrBoolean, Decl(b.ts, 13, 3), Decl(b.ts, 15, 3))
->c.inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 16, 9), Decl(a.js, 34, 9))
+var number: number;
+>number : Symbol(number, Decl(b.ts, 15, 3), Decl(b.ts, 16, 3))
+
+var number = c.inMultiple;
+>number : Symbol(number, Decl(b.ts, 15, 3), Decl(b.ts, 16, 3))
+>c.inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 18, 9), Decl(a.js, 37, 9))
 >c : Symbol(c, Decl(b.ts, 0, 3))
->inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 16, 9), Decl(a.js, 34, 9))
+>inMultiple : Symbol(C.inMultiple, Decl(a.js, 7, 9), Decl(a.js, 18, 9), Decl(a.js, 37, 9))
+
+var stringOrBooleanOrUndefined : string | boolean | undefined;
+>stringOrBooleanOrUndefined : Symbol(stringOrBooleanOrUndefined, Decl(b.ts, 17, 3), Decl(b.ts, 18, 3))
+
+var stringOrBooleanOrUndefined = c.inMultipleMethods;
+>stringOrBooleanOrUndefined : Symbol(stringOrBooleanOrUndefined, Decl(b.ts, 17, 3), Decl(b.ts, 18, 3))
+>c.inMultipleMethods : Symbol(C.inMultipleMethods, Decl(a.js, 19, 35), Decl(a.js, 38, 32))
+>c : Symbol(c, Decl(b.ts, 0, 3))
+>inMultipleMethods : Symbol(C.inMultipleMethods, Decl(a.js, 19, 35), Decl(a.js, 38, 32))
+
+var any: any;
+>any : Symbol(any, Decl(b.ts, 19, 3), Decl(b.ts, 20, 3))
+
+var any = c.inMethodNullable;
+>any : Symbol(any, Decl(b.ts, 19, 3), Decl(b.ts, 20, 3))
+>c.inMethodNullable : Symbol(C.inMethodNullable, Decl(a.js, 12, 30), Decl(a.js, 16, 36))
+>c : Symbol(c, Decl(b.ts, 0, 3))
+>inMethodNullable : Symbol(C.inMethodNullable, Decl(a.js, 12, 30), Decl(a.js, 16, 36))
 
 
 var stringOrNumberOrUndefined = C.inStaticMethod;
 >stringOrNumberOrUndefined : Symbol(stringOrNumberOrUndefined, Decl(b.ts, 5, 3), Decl(b.ts, 7, 3), Decl(b.ts, 8, 3), Decl(b.ts, 9, 3), Decl(b.ts, 10, 3) ... and 6 more)
->C.inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 54, 28), Decl(a.js, 57, 14))
+>C.inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 58, 28), Decl(a.js, 61, 14))
 >C : Symbol(C, Decl(a.js, 0, 0))
->inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 54, 28), Decl(a.js, 57, 14))
+>inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 58, 28), Decl(a.js, 61, 14))
 
 var stringOrNumberOrUndefined = C.inStaticGetter;
 >stringOrNumberOrUndefined : Symbol(stringOrNumberOrUndefined, Decl(b.ts, 5, 3), Decl(b.ts, 7, 3), Decl(b.ts, 8, 3), Decl(b.ts, 9, 3), Decl(b.ts, 10, 3) ... and 6 more)
->C.inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 71, 28), Decl(a.js, 74, 14))
+>C.inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 75, 28), Decl(a.js, 78, 14))
 >C : Symbol(C, Decl(a.js, 0, 0))
->inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 71, 28), Decl(a.js, 74, 14))
+>inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 75, 28), Decl(a.js, 78, 14))
 
 var stringOrNumberOrUndefined = C.inStaticSetter;
 >stringOrNumberOrUndefined : Symbol(stringOrNumberOrUndefined, Decl(b.ts, 5, 3), Decl(b.ts, 7, 3), Decl(b.ts, 8, 3), Decl(b.ts, 9, 3), Decl(b.ts, 10, 3) ... and 6 more)
->C.inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 79, 28), Decl(a.js, 82, 14))
+>C.inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 83, 28), Decl(a.js, 86, 14))
 >C : Symbol(C, Decl(a.js, 0, 0))
->inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 79, 28), Decl(a.js, 82, 14))
+>inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 83, 28), Decl(a.js, 86, 14))
 
 var stringOrNumberOrUndefined = C.inStaticPropertyDeclaration;
 >stringOrNumberOrUndefined : Symbol(stringOrNumberOrUndefined, Decl(b.ts, 5, 3), Decl(b.ts, 7, 3), Decl(b.ts, 8, 3), Decl(b.ts, 9, 3), Decl(b.ts, 10, 3) ... and 6 more)
->C.inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 87, 28), Decl(a.js, 90, 14))
+>C.inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 91, 28), Decl(a.js, 94, 14))
 >C : Symbol(C, Decl(a.js, 0, 0))
->inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 87, 28), Decl(a.js, 90, 14))
+>inStaticPropertyDeclaration : Symbol(C.inStaticPropertyDeclaration, Decl(a.js, 91, 28), Decl(a.js, 94, 14))
 
 var stringOrNumberOrUndefined = C.inStaticNestedArrowFunction;
 >stringOrNumberOrUndefined : Symbol(stringOrNumberOrUndefined, Decl(b.ts, 5, 3), Decl(b.ts, 7, 3), Decl(b.ts, 8, 3), Decl(b.ts, 9, 3), Decl(b.ts, 10, 3) ... and 6 more)
->C.inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 62, 32), Decl(a.js, 65, 18))
+>C.inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 66, 32), Decl(a.js, 69, 18))
 >C : Symbol(C, Decl(a.js, 0, 0))
->inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 62, 32), Decl(a.js, 65, 18))
+>inStaticNestedArrowFunction : Symbol(C.inStaticNestedArrowFunction, Decl(a.js, 66, 32), Decl(a.js, 69, 18))
 
diff --git a/tests/baselines/reference/inferringClassMembersFromAssignments.types b/tests/baselines/reference/inferringClassMembersFromAssignments.types
index e462a04d198..3d168707fe6 100644
--- a/tests/baselines/reference/inferringClassMembersFromAssignments.types
+++ b/tests/baselines/reference/inferringClassMembersFromAssignments.types
@@ -26,9 +26,9 @@ class C {
         }
         this.inMultiple = 0;
 >this.inMultiple = 0 : 0
->this.inMultiple : string | number | boolean
+>this.inMultiple : number
 >this : this
->inMultiple : string | number | boolean
+>inMultiple : number
 >0 : 0
     }
     method() {
@@ -46,6 +46,13 @@ class C {
 >this : this
 >inMethod : string | number | undefined
 >0 : 0
+
+            this.inMethodNullable = null;
+>this.inMethodNullable = null : null
+>this.inMethodNullable : any
+>this : this
+>inMethodNullable : any
+>null : null
         }
         else {
             this.inMethod = "string"
@@ -54,12 +61,26 @@ class C {
 >this : this
 >inMethod : string | number | undefined
 >"string" : "string"
+
+            this.inMethodNullable = undefined;
+>this.inMethodNullable = undefined : undefined
+>this.inMethodNullable : any
+>this : this
+>inMethodNullable : any
+>undefined : undefined
         }
         this.inMultiple = "string";
 >this.inMultiple = "string" : "string"
->this.inMultiple : string | number | boolean
+>this.inMultiple : number
 >this : this
->inMultiple : string | number | boolean
+>inMultiple : number
+>"string" : "string"
+
+        this.inMultipleMethods = "string";
+>this.inMultipleMethods = "string" : "string"
+>this.inMultipleMethods : string | boolean | undefined
+>this : this
+>inMultipleMethods : string | boolean | undefined
 >"string" : "string"
 
         var action = () => {
@@ -115,9 +136,16 @@ class C {
         }
         this.inMultiple = false;
 >this.inMultiple = false : false
->this.inMultiple : string | number | boolean
+>this.inMultiple : number
 >this : this
->inMultiple : string | number | boolean
+>inMultiple : number
+>false : false
+
+        this.inMultipleMethods = false;
+>this.inMultipleMethods = false : false
+>this.inMultipleMethods : string | boolean | undefined
+>this : this
+>inMultipleMethods : string | boolean | undefined
 >false : false
     }
     set() {
@@ -352,11 +380,32 @@ var stringOrNumberOrUndefined = c.inNestedArrowFunction
 var stringOrNumberOrBoolean: string | number | boolean;
 >stringOrNumberOrBoolean : string | number | boolean
 
-var stringOrNumberOrBoolean = c.inMultiple;
->stringOrNumberOrBoolean : string | number | boolean
->c.inMultiple : string | number | boolean
+var number: number;
+>number : number
+
+var number = c.inMultiple;
+>number : number
+>c.inMultiple : number
 >c : C
->inMultiple : string | number | boolean
+>inMultiple : number
+
+var stringOrBooleanOrUndefined : string | boolean | undefined;
+>stringOrBooleanOrUndefined : string | boolean | undefined
+
+var stringOrBooleanOrUndefined = c.inMultipleMethods;
+>stringOrBooleanOrUndefined : string | boolean | undefined
+>c.inMultipleMethods : string | boolean | undefined
+>c : C
+>inMultipleMethods : string | boolean | undefined
+
+var any: any;
+>any : any
+
+var any = c.inMethodNullable;
+>any : any
+>c.inMethodNullable : any
+>c : C
+>inMethodNullable : any
 
 
 var stringOrNumberOrUndefined = C.inStaticMethod;
diff --git a/tests/baselines/reference/typeFromJSConstructor.errors.txt b/tests/baselines/reference/typeFromJSConstructor.errors.txt
new file mode 100644
index 00000000000..ffcf5393f51
--- /dev/null
+++ b/tests/baselines/reference/typeFromJSConstructor.errors.txt
@@ -0,0 +1,52 @@
+tests/cases/conformance/salsa/a.js(10,5): error TS7008: Member 'twices' implicitly has an 'any[]' type.
+tests/cases/conformance/salsa/a.js(14,5): error TS2322: Type '"hi"' is not assignable to type 'number'.
+tests/cases/conformance/salsa/a.js(21,5): error TS2322: Type 'false' is not assignable to type 'number'.
+tests/cases/conformance/salsa/a.js(24,5): error TS2322: Type 'null' is not assignable to type 'string | undefined'.
+tests/cases/conformance/salsa/a.js(25,5): error TS2322: Type 'false' is not assignable to type 'string | undefined'.
+tests/cases/conformance/salsa/a.js(26,5): error TS2531: Object is possibly 'null'.
+
+
+==== tests/cases/conformance/salsa/a.js (6 errors) ====
+    function Installer () {
+        // arg: number
+        this.arg = 0
+        // unknown: string | boolean | null
+        this.unknown = null
+        // twice: string | undefined
+        this.twice = undefined
+        this.twice = 'hi'
+        // twices: any[] | null
+        this.twices = []
+        ~~~~~~~~~~~~~~~~
+!!! error TS7008: Member 'twices' implicitly has an 'any[]' type.
+        this.twices = null
+    }
+    Installer.prototype.first = function () {
+        this.arg = 'hi' // error
+        ~~~~~~~~
+!!! error TS2322: Type '"hi"' is not assignable to type 'number'.
+        this.unknown = 'hi' // ok
+        this.newProperty = 1 // ok: number | boolean
+        this.twice = undefined // ok
+        this.twice = 'hi' // ok
+    }
+    Installer.prototype.second = function () {
+        this.arg = false // error
+        ~~~~~~~~
+!!! error TS2322: Type 'false' is not assignable to type 'number'.
+        this.unknown = false // ok
+        this.newProperty = false // ok
+        this.twice = null // error
+        ~~~~~~~~~~
+!!! error TS2322: Type 'null' is not assignable to type 'string | undefined'.
+        this.twice = false // error
+        ~~~~~~~~~~
+!!! error TS2322: Type 'false' is not assignable to type 'string | undefined'.
+        this.twices.push(1) // error: Object is possibly null
+        ~~~~~~~~~~~
+!!! error TS2531: Object is possibly 'null'.
+        if (this.twices != null) {
+            this.twices.push('hi')
+        }
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/typeFromJSConstructor.symbols b/tests/baselines/reference/typeFromJSConstructor.symbols
new file mode 100644
index 00000000000..541eeada65f
--- /dev/null
+++ b/tests/baselines/reference/typeFromJSConstructor.symbols
@@ -0,0 +1,111 @@
+=== tests/cases/conformance/salsa/a.js ===
+function Installer () {
+>Installer : Symbol(Installer, Decl(a.js, 0, 0))
+
+    // arg: number
+    this.arg = 0
+>arg : Symbol(Installer.arg, Decl(a.js, 0, 23), Decl(a.js, 12, 41), Decl(a.js, 19, 42))
+
+    // unknown: string | boolean | null
+    this.unknown = null
+>unknown : Symbol(Installer.unknown, Decl(a.js, 2, 16), Decl(a.js, 13, 19), Decl(a.js, 20, 20))
+
+    // twice: string | undefined
+    this.twice = undefined
+>twice : Symbol(Installer.twice, Decl(a.js, 4, 23), Decl(a.js, 6, 26), Decl(a.js, 15, 24), Decl(a.js, 16, 26), Decl(a.js, 22, 28) ... and 1 more)
+>undefined : Symbol(undefined)
+
+    this.twice = 'hi'
+>twice : Symbol(Installer.twice, Decl(a.js, 4, 23), Decl(a.js, 6, 26), Decl(a.js, 15, 24), Decl(a.js, 16, 26), Decl(a.js, 22, 28) ... and 1 more)
+
+    // twices: any[] | null
+    this.twices = []
+>twices : Symbol(Installer.twices, Decl(a.js, 7, 21), Decl(a.js, 9, 20))
+
+    this.twices = null
+>twices : Symbol(Installer.twices, Decl(a.js, 7, 21), Decl(a.js, 9, 20))
+}
+Installer.prototype.first = function () {
+>Installer.prototype : Symbol(Installer.first, Decl(a.js, 11, 1))
+>Installer : Symbol(Installer, Decl(a.js, 0, 0))
+>prototype : Symbol(Function.prototype, Decl(lib.d.ts, --, --))
+>first : Symbol(Installer.first, Decl(a.js, 11, 1))
+
+    this.arg = 'hi' // error
+>this.arg : Symbol(Installer.arg, Decl(a.js, 0, 23), Decl(a.js, 12, 41), Decl(a.js, 19, 42))
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>arg : Symbol(Installer.arg, Decl(a.js, 0, 23), Decl(a.js, 12, 41), Decl(a.js, 19, 42))
+
+    this.unknown = 'hi' // ok
+>this.unknown : Symbol(Installer.unknown, Decl(a.js, 2, 16), Decl(a.js, 13, 19), Decl(a.js, 20, 20))
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>unknown : Symbol(Installer.unknown, Decl(a.js, 2, 16), Decl(a.js, 13, 19), Decl(a.js, 20, 20))
+
+    this.newProperty = 1 // ok: number | boolean
+>this.newProperty : Symbol(Installer.newProperty, Decl(a.js, 14, 23), Decl(a.js, 21, 24))
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>newProperty : Symbol(Installer.newProperty, Decl(a.js, 14, 23), Decl(a.js, 21, 24))
+
+    this.twice = undefined // ok
+>this.twice : Symbol(Installer.twice, Decl(a.js, 4, 23), Decl(a.js, 6, 26), Decl(a.js, 15, 24), Decl(a.js, 16, 26), Decl(a.js, 22, 28) ... and 1 more)
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>twice : Symbol(Installer.twice, Decl(a.js, 4, 23), Decl(a.js, 6, 26), Decl(a.js, 15, 24), Decl(a.js, 16, 26), Decl(a.js, 22, 28) ... and 1 more)
+>undefined : Symbol(undefined)
+
+    this.twice = 'hi' // ok
+>this.twice : Symbol(Installer.twice, Decl(a.js, 4, 23), Decl(a.js, 6, 26), Decl(a.js, 15, 24), Decl(a.js, 16, 26), Decl(a.js, 22, 28) ... and 1 more)
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>twice : Symbol(Installer.twice, Decl(a.js, 4, 23), Decl(a.js, 6, 26), Decl(a.js, 15, 24), Decl(a.js, 16, 26), Decl(a.js, 22, 28) ... and 1 more)
+}
+Installer.prototype.second = function () {
+>Installer.prototype : Symbol(Installer.second, Decl(a.js, 18, 1))
+>Installer : Symbol(Installer, Decl(a.js, 0, 0))
+>prototype : Symbol(Function.prototype, Decl(lib.d.ts, --, --))
+>second : Symbol(Installer.second, Decl(a.js, 18, 1))
+
+    this.arg = false // error
+>this.arg : Symbol(Installer.arg, Decl(a.js, 0, 23), Decl(a.js, 12, 41), Decl(a.js, 19, 42))
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>arg : Symbol(Installer.arg, Decl(a.js, 0, 23), Decl(a.js, 12, 41), Decl(a.js, 19, 42))
+
+    this.unknown = false // ok
+>this.unknown : Symbol(Installer.unknown, Decl(a.js, 2, 16), Decl(a.js, 13, 19), Decl(a.js, 20, 20))
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>unknown : Symbol(Installer.unknown, Decl(a.js, 2, 16), Decl(a.js, 13, 19), Decl(a.js, 20, 20))
+
+    this.newProperty = false // ok
+>this.newProperty : Symbol(Installer.newProperty, Decl(a.js, 14, 23), Decl(a.js, 21, 24))
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>newProperty : Symbol(Installer.newProperty, Decl(a.js, 14, 23), Decl(a.js, 21, 24))
+
+    this.twice = null // error
+>this.twice : Symbol(Installer.twice, Decl(a.js, 4, 23), Decl(a.js, 6, 26), Decl(a.js, 15, 24), Decl(a.js, 16, 26), Decl(a.js, 22, 28) ... and 1 more)
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>twice : Symbol(Installer.twice, Decl(a.js, 4, 23), Decl(a.js, 6, 26), Decl(a.js, 15, 24), Decl(a.js, 16, 26), Decl(a.js, 22, 28) ... and 1 more)
+
+    this.twice = false // error
+>this.twice : Symbol(Installer.twice, Decl(a.js, 4, 23), Decl(a.js, 6, 26), Decl(a.js, 15, 24), Decl(a.js, 16, 26), Decl(a.js, 22, 28) ... and 1 more)
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>twice : Symbol(Installer.twice, Decl(a.js, 4, 23), Decl(a.js, 6, 26), Decl(a.js, 15, 24), Decl(a.js, 16, 26), Decl(a.js, 22, 28) ... and 1 more)
+
+    this.twices.push(1) // error: Object is possibly null
+>this.twices.push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+>this.twices : Symbol(Installer.twices, Decl(a.js, 7, 21), Decl(a.js, 9, 20))
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>twices : Symbol(Installer.twices, Decl(a.js, 7, 21), Decl(a.js, 9, 20))
+>push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+
+    if (this.twices != null) {
+>this.twices : Symbol(Installer.twices, Decl(a.js, 7, 21), Decl(a.js, 9, 20))
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>twices : Symbol(Installer.twices, Decl(a.js, 7, 21), Decl(a.js, 9, 20))
+
+        this.twices.push('hi')
+>this.twices.push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+>this.twices : Symbol(Installer.twices, Decl(a.js, 7, 21), Decl(a.js, 9, 20))
+>this : Symbol(Installer, Decl(a.js, 0, 0))
+>twices : Symbol(Installer.twices, Decl(a.js, 7, 21), Decl(a.js, 9, 20))
+>push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+    }
+}
+
diff --git a/tests/baselines/reference/typeFromJSConstructor.types b/tests/baselines/reference/typeFromJSConstructor.types
new file mode 100644
index 00000000000..f7dd925ed5c
--- /dev/null
+++ b/tests/baselines/reference/typeFromJSConstructor.types
@@ -0,0 +1,165 @@
+=== tests/cases/conformance/salsa/a.js ===
+function Installer () {
+>Installer : () => void
+
+    // arg: number
+    this.arg = 0
+>this.arg = 0 : 0
+>this.arg : any
+>this : any
+>arg : any
+>0 : 0
+
+    // unknown: string | boolean | null
+    this.unknown = null
+>this.unknown = null : null
+>this.unknown : any
+>this : any
+>unknown : any
+>null : null
+
+    // twice: string | undefined
+    this.twice = undefined
+>this.twice = undefined : undefined
+>this.twice : any
+>this : any
+>twice : any
+>undefined : undefined
+
+    this.twice = 'hi'
+>this.twice = 'hi' : "hi"
+>this.twice : any
+>this : any
+>twice : any
+>'hi' : "hi"
+
+    // twices: any[] | null
+    this.twices = []
+>this.twices = [] : never[]
+>this.twices : any
+>this : any
+>twices : any
+>[] : never[]
+
+    this.twices = null
+>this.twices = null : null
+>this.twices : any
+>this : any
+>twices : any
+>null : null
+}
+Installer.prototype.first = function () {
+>Installer.prototype.first = function () {    this.arg = 'hi' // error    this.unknown = 'hi' // ok    this.newProperty = 1 // ok: number | boolean    this.twice = undefined // ok    this.twice = 'hi' // ok} : () => void
+>Installer.prototype.first : any
+>Installer.prototype : any
+>Installer : () => void
+>prototype : any
+>first : any
+>function () {    this.arg = 'hi' // error    this.unknown = 'hi' // ok    this.newProperty = 1 // ok: number | boolean    this.twice = undefined // ok    this.twice = 'hi' // ok} : () => void
+
+    this.arg = 'hi' // error
+>this.arg = 'hi' : "hi"
+>this.arg : number
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>arg : number
+>'hi' : "hi"
+
+    this.unknown = 'hi' // ok
+>this.unknown = 'hi' : "hi"
+>this.unknown : string | boolean | null
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>unknown : string | boolean | null
+>'hi' : "hi"
+
+    this.newProperty = 1 // ok: number | boolean
+>this.newProperty = 1 : 1
+>this.newProperty : number | boolean | undefined
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>newProperty : number | boolean | undefined
+>1 : 1
+
+    this.twice = undefined // ok
+>this.twice = undefined : undefined
+>this.twice : string | undefined
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>twice : string | undefined
+>undefined : undefined
+
+    this.twice = 'hi' // ok
+>this.twice = 'hi' : "hi"
+>this.twice : string | undefined
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>twice : string | undefined
+>'hi' : "hi"
+}
+Installer.prototype.second = function () {
+>Installer.prototype.second = function () {    this.arg = false // error    this.unknown = false // ok    this.newProperty = false // ok    this.twice = null // error    this.twice = false // error    this.twices.push(1) // error: Object is possibly null    if (this.twices != null) {        this.twices.push('hi')    }} : () => void
+>Installer.prototype.second : any
+>Installer.prototype : any
+>Installer : () => void
+>prototype : any
+>second : any
+>function () {    this.arg = false // error    this.unknown = false // ok    this.newProperty = false // ok    this.twice = null // error    this.twice = false // error    this.twices.push(1) // error: Object is possibly null    if (this.twices != null) {        this.twices.push('hi')    }} : () => void
+
+    this.arg = false // error
+>this.arg = false : false
+>this.arg : number
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>arg : number
+>false : false
+
+    this.unknown = false // ok
+>this.unknown = false : false
+>this.unknown : string | boolean | null
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>unknown : string | boolean | null
+>false : false
+
+    this.newProperty = false // ok
+>this.newProperty = false : false
+>this.newProperty : number | boolean | undefined
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>newProperty : number | boolean | undefined
+>false : false
+
+    this.twice = null // error
+>this.twice = null : null
+>this.twice : string | undefined
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>twice : string | undefined
+>null : null
+
+    this.twice = false // error
+>this.twice = false : false
+>this.twice : string | undefined
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>twice : string | undefined
+>false : false
+
+    this.twices.push(1) // error: Object is possibly null
+>this.twices.push(1) : number
+>this.twices.push : (...items: any[]) => number
+>this.twices : any[] | null
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>twices : any[] | null
+>push : (...items: any[]) => number
+>1 : 1
+
+    if (this.twices != null) {
+>this.twices != null : boolean
+>this.twices : any[] | null
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>twices : any[] | null
+>null : null
+
+        this.twices.push('hi')
+>this.twices.push('hi') : number
+>this.twices.push : (...items: any[]) => number
+>this.twices : any[]
+>this : { arg: number; unknown: string | boolean | null; twice: string | undefined; twices: any[] | null; first: () => void; newProperty: number | boolean | undefined; second: () => void; }
+>twices : any[]
+>push : (...items: any[]) => number
+>'hi' : "hi"
+    }
+}
+
diff --git a/tests/baselines/reference/typeFromJSInitializer.errors.txt b/tests/baselines/reference/typeFromJSInitializer.errors.txt
new file mode 100644
index 00000000000..08d66a2a9f3
--- /dev/null
+++ b/tests/baselines/reference/typeFromJSInitializer.errors.txt
@@ -0,0 +1,75 @@
+tests/cases/conformance/salsa/a.js(3,5): error TS7008: Member 'unknown' implicitly has an 'any' type.
+tests/cases/conformance/salsa/a.js(4,5): error TS7008: Member 'unknowable' implicitly has an 'any' type.
+tests/cases/conformance/salsa/a.js(5,5): error TS7008: Member 'empty' implicitly has an 'any[]' type.
+tests/cases/conformance/salsa/a.js(25,12): error TS7006: Parameter 'a' implicitly has an 'any' type.
+tests/cases/conformance/salsa/a.js(25,29): error TS7006: Parameter 'l' implicitly has an 'any[]' type.
+tests/cases/conformance/salsa/a.js(37,5): error TS2322: Type '"error"' is not assignable to type 'number | undefined'.
+
+
+==== tests/cases/conformance/salsa/a.js (6 errors) ====
+    function A () {
+        // should get any on this-assignments in constructor
+        this.unknown = null
+        ~~~~~~~~~~~~~~~~~~~
+!!! error TS7008: Member 'unknown' implicitly has an 'any' type.
+        this.unknowable = undefined
+        ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS7008: Member 'unknowable' implicitly has an 'any' type.
+        this.empty = []
+        ~~~~~~~~~~~~~~~
+!!! error TS7008: Member 'empty' implicitly has an 'any[]' type.
+    }
+    var a = new A()
+    a.unknown = 1
+    a.unknown = true
+    a.unknown = {}
+    a.unknown = 'hi'
+    a.unknowable = 1
+    a.unknowable = true
+    a.unknowable = {}
+    a.unknowable = 'hi'
+    a.empty.push(1)
+    a.empty.push(true)
+    a.empty.push({})
+    a.empty.push('hi')
+    
+    /** @type {number | undefined} */
+    var n;
+    
+    // should get any on parameter initialisers
+    function f(a = null, b = n, l = []) {
+               ~~~~~~~~
+!!! error TS7006: Parameter 'a' implicitly has an 'any' type.
+                                ~~~~~~
+!!! error TS7006: Parameter 'l' implicitly has an 'any[]' type.
+        // a should be any
+        a = undefined
+        a = null
+        a = 1
+        a = true
+        a = {}
+        a = 'ok'
+    
+        // b should be number | undefined, not any
+        b = 1
+        b = undefined
+        b = 'error'
+        ~
+!!! error TS2322: Type '"error"' is not assignable to type 'number | undefined'.
+    
+        // l should be any[]
+        l.push(1)
+        l.push('ok')
+    }
+    
+    // should get any on variable initialisers
+    var u = undefined;
+    var l = [];
+    u = undefined
+    u = 1
+    u = true
+    u = {}
+    u = 'ok'
+    
+    l.push('ok')
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/typeFromJSInitializer.symbols b/tests/baselines/reference/typeFromJSInitializer.symbols
new file mode 100644
index 00000000000..3c9d9657421
--- /dev/null
+++ b/tests/baselines/reference/typeFromJSInitializer.symbols
@@ -0,0 +1,171 @@
+=== tests/cases/conformance/salsa/a.js ===
+function A () {
+>A : Symbol(A, Decl(a.js, 0, 0))
+
+    // should get any on this-assignments in constructor
+    this.unknown = null
+>unknown : Symbol(A.unknown, Decl(a.js, 0, 15))
+
+    this.unknowable = undefined
+>unknowable : Symbol(A.unknowable, Decl(a.js, 2, 23))
+>undefined : Symbol(undefined)
+
+    this.empty = []
+>empty : Symbol(A.empty, Decl(a.js, 3, 31))
+}
+var a = new A()
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>A : Symbol(A, Decl(a.js, 0, 0))
+
+a.unknown = 1
+>a.unknown : Symbol(A.unknown, Decl(a.js, 0, 15))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>unknown : Symbol(A.unknown, Decl(a.js, 0, 15))
+
+a.unknown = true
+>a.unknown : Symbol(A.unknown, Decl(a.js, 0, 15))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>unknown : Symbol(A.unknown, Decl(a.js, 0, 15))
+
+a.unknown = {}
+>a.unknown : Symbol(A.unknown, Decl(a.js, 0, 15))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>unknown : Symbol(A.unknown, Decl(a.js, 0, 15))
+
+a.unknown = 'hi'
+>a.unknown : Symbol(A.unknown, Decl(a.js, 0, 15))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>unknown : Symbol(A.unknown, Decl(a.js, 0, 15))
+
+a.unknowable = 1
+>a.unknowable : Symbol(A.unknowable, Decl(a.js, 2, 23))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>unknowable : Symbol(A.unknowable, Decl(a.js, 2, 23))
+
+a.unknowable = true
+>a.unknowable : Symbol(A.unknowable, Decl(a.js, 2, 23))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>unknowable : Symbol(A.unknowable, Decl(a.js, 2, 23))
+
+a.unknowable = {}
+>a.unknowable : Symbol(A.unknowable, Decl(a.js, 2, 23))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>unknowable : Symbol(A.unknowable, Decl(a.js, 2, 23))
+
+a.unknowable = 'hi'
+>a.unknowable : Symbol(A.unknowable, Decl(a.js, 2, 23))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>unknowable : Symbol(A.unknowable, Decl(a.js, 2, 23))
+
+a.empty.push(1)
+>a.empty.push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+>a.empty : Symbol(A.empty, Decl(a.js, 3, 31))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>empty : Symbol(A.empty, Decl(a.js, 3, 31))
+>push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+
+a.empty.push(true)
+>a.empty.push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+>a.empty : Symbol(A.empty, Decl(a.js, 3, 31))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>empty : Symbol(A.empty, Decl(a.js, 3, 31))
+>push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+
+a.empty.push({})
+>a.empty.push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+>a.empty : Symbol(A.empty, Decl(a.js, 3, 31))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>empty : Symbol(A.empty, Decl(a.js, 3, 31))
+>push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+
+a.empty.push('hi')
+>a.empty.push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+>a.empty : Symbol(A.empty, Decl(a.js, 3, 31))
+>a : Symbol(a, Decl(a.js, 6, 3), Decl(a.js, 8, 16))
+>empty : Symbol(A.empty, Decl(a.js, 3, 31))
+>push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+
+/** @type {number | undefined} */
+var n;
+>n : Symbol(n, Decl(a.js, 21, 3))
+
+// should get any on parameter initialisers
+function f(a = null, b = n, l = []) {
+>f : Symbol(f, Decl(a.js, 21, 6))
+>a : Symbol(a, Decl(a.js, 24, 11))
+>b : Symbol(b, Decl(a.js, 24, 20))
+>n : Symbol(n, Decl(a.js, 21, 3))
+>l : Symbol(l, Decl(a.js, 24, 27))
+
+    // a should be any
+    a = undefined
+>a : Symbol(a, Decl(a.js, 24, 11))
+>undefined : Symbol(undefined)
+
+    a = null
+>a : Symbol(a, Decl(a.js, 24, 11))
+
+    a = 1
+>a : Symbol(a, Decl(a.js, 24, 11))
+
+    a = true
+>a : Symbol(a, Decl(a.js, 24, 11))
+
+    a = {}
+>a : Symbol(a, Decl(a.js, 24, 11))
+
+    a = 'ok'
+>a : Symbol(a, Decl(a.js, 24, 11))
+
+    // b should be number | undefined, not any
+    b = 1
+>b : Symbol(b, Decl(a.js, 24, 20))
+
+    b = undefined
+>b : Symbol(b, Decl(a.js, 24, 20))
+>undefined : Symbol(undefined)
+
+    b = 'error'
+>b : Symbol(b, Decl(a.js, 24, 20))
+
+    // l should be any[]
+    l.push(1)
+>l.push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+>l : Symbol(l, Decl(a.js, 24, 27))
+>push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+
+    l.push('ok')
+>l.push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+>l : Symbol(l, Decl(a.js, 24, 27))
+>push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+}
+
+// should get any on variable initialisers
+var u = undefined;
+>u : Symbol(u, Decl(a.js, 44, 3))
+>undefined : Symbol(undefined)
+
+var l = [];
+>l : Symbol(l, Decl(a.js, 45, 3))
+
+u = undefined
+>u : Symbol(u, Decl(a.js, 44, 3))
+>undefined : Symbol(undefined)
+
+u = 1
+>u : Symbol(u, Decl(a.js, 44, 3))
+
+u = true
+>u : Symbol(u, Decl(a.js, 44, 3))
+
+u = {}
+>u : Symbol(u, Decl(a.js, 44, 3))
+
+u = 'ok'
+>u : Symbol(u, Decl(a.js, 44, 3))
+
+l.push('ok')
+>l.push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+>l : Symbol(l, Decl(a.js, 45, 3))
+>push : Symbol(Array.push, Decl(lib.d.ts, --, --))
+
diff --git a/tests/baselines/reference/typeFromJSInitializer.types b/tests/baselines/reference/typeFromJSInitializer.types
new file mode 100644
index 00000000000..cc994c9a616
--- /dev/null
+++ b/tests/baselines/reference/typeFromJSInitializer.types
@@ -0,0 +1,241 @@
+=== tests/cases/conformance/salsa/a.js ===
+function A () {
+>A : () => void
+
+    // should get any on this-assignments in constructor
+    this.unknown = null
+>this.unknown = null : null
+>this.unknown : any
+>this : any
+>unknown : any
+>null : null
+
+    this.unknowable = undefined
+>this.unknowable = undefined : undefined
+>this.unknowable : any
+>this : any
+>unknowable : any
+>undefined : undefined
+
+    this.empty = []
+>this.empty = [] : never[]
+>this.empty : any
+>this : any
+>empty : any
+>[] : never[]
+}
+var a = new A()
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>new A() : { unknown: any; unknowable: any; empty: any[]; }
+>A : () => void
+
+a.unknown = 1
+>a.unknown = 1 : 1
+>a.unknown : any
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>unknown : any
+>1 : 1
+
+a.unknown = true
+>a.unknown = true : true
+>a.unknown : any
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>unknown : any
+>true : true
+
+a.unknown = {}
+>a.unknown = {} : { [x: string]: any; }
+>a.unknown : any
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>unknown : any
+>{} : { [x: string]: any; }
+
+a.unknown = 'hi'
+>a.unknown = 'hi' : "hi"
+>a.unknown : any
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>unknown : any
+>'hi' : "hi"
+
+a.unknowable = 1
+>a.unknowable = 1 : 1
+>a.unknowable : any
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>unknowable : any
+>1 : 1
+
+a.unknowable = true
+>a.unknowable = true : true
+>a.unknowable : any
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>unknowable : any
+>true : true
+
+a.unknowable = {}
+>a.unknowable = {} : { [x: string]: any; }
+>a.unknowable : any
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>unknowable : any
+>{} : { [x: string]: any; }
+
+a.unknowable = 'hi'
+>a.unknowable = 'hi' : "hi"
+>a.unknowable : any
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>unknowable : any
+>'hi' : "hi"
+
+a.empty.push(1)
+>a.empty.push(1) : number
+>a.empty.push : (...items: any[]) => number
+>a.empty : any[]
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>empty : any[]
+>push : (...items: any[]) => number
+>1 : 1
+
+a.empty.push(true)
+>a.empty.push(true) : number
+>a.empty.push : (...items: any[]) => number
+>a.empty : any[]
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>empty : any[]
+>push : (...items: any[]) => number
+>true : true
+
+a.empty.push({})
+>a.empty.push({}) : number
+>a.empty.push : (...items: any[]) => number
+>a.empty : any[]
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>empty : any[]
+>push : (...items: any[]) => number
+>{} : {}
+
+a.empty.push('hi')
+>a.empty.push('hi') : number
+>a.empty.push : (...items: any[]) => number
+>a.empty : any[]
+>a : { unknown: any; unknowable: any; empty: any[]; }
+>empty : any[]
+>push : (...items: any[]) => number
+>'hi' : "hi"
+
+/** @type {number | undefined} */
+var n;
+>n : number | undefined
+
+// should get any on parameter initialisers
+function f(a = null, b = n, l = []) {
+>f : (a?: any, b?: number | undefined, l?: any[]) => void
+>a : any
+>null : null
+>b : number | undefined
+>n : number | undefined
+>l : any[]
+>[] : never[]
+
+    // a should be any
+    a = undefined
+>a = undefined : undefined
+>a : any
+>undefined : undefined
+
+    a = null
+>a = null : null
+>a : any
+>null : null
+
+    a = 1
+>a = 1 : 1
+>a : any
+>1 : 1
+
+    a = true
+>a = true : true
+>a : any
+>true : true
+
+    a = {}
+>a = {} : {}
+>a : any
+>{} : {}
+
+    a = 'ok'
+>a = 'ok' : "ok"
+>a : any
+>'ok' : "ok"
+
+    // b should be number | undefined, not any
+    b = 1
+>b = 1 : 1
+>b : number | undefined
+>1 : 1
+
+    b = undefined
+>b = undefined : undefined
+>b : number | undefined
+>undefined : undefined
+
+    b = 'error'
+>b = 'error' : "error"
+>b : number | undefined
+>'error' : "error"
+
+    // l should be any[]
+    l.push(1)
+>l.push(1) : number
+>l.push : (...items: any[]) => number
+>l : any[]
+>push : (...items: any[]) => number
+>1 : 1
+
+    l.push('ok')
+>l.push('ok') : number
+>l.push : (...items: any[]) => number
+>l : any[]
+>push : (...items: any[]) => number
+>'ok' : "ok"
+}
+
+// should get any on variable initialisers
+var u = undefined;
+>u : any
+>undefined : undefined
+
+var l = [];
+>l : any[]
+>[] : never[]
+
+u = undefined
+>u = undefined : undefined
+>u : any
+>undefined : undefined
+
+u = 1
+>u = 1 : 1
+>u : any
+>1 : 1
+
+u = true
+>u = true : true
+>u : any
+>true : true
+
+u = {}
+>u = {} : {}
+>u : any
+>{} : {}
+
+u = 'ok'
+>u = 'ok' : "ok"
+>u : any
+>'ok' : "ok"
+
+l.push('ok')
+>l.push('ok') : number
+>l.push : (...items: any[]) => number
+>l : any[]
+>push : (...items: any[]) => number
+>'ok' : "ok"
+
diff --git a/tests/baselines/reference/typeFromPropertyAssignment22.errors.txt b/tests/baselines/reference/typeFromPropertyAssignment22.errors.txt
index 969824cb33f..e688c37e30e 100644
--- a/tests/baselines/reference/typeFromPropertyAssignment22.errors.txt
+++ b/tests/baselines/reference/typeFromPropertyAssignment22.errors.txt
@@ -1,5 +1,4 @@
-tests/cases/conformance/salsa/npm-install.js(12,1): error TS2322: Type 'string | number' is not assignable to type 'number | undefined'.
-  Type 'string' is not assignable to type 'number | undefined'.
+tests/cases/conformance/salsa/npm-install.js(7,9): error TS2322: Type '"hi"' is not assignable to type 'number'.
 
 
 ==== tests/cases/conformance/salsa/npm-install.js (1 errors) ====
@@ -10,12 +9,11 @@ tests/cases/conformance/salsa/npm-install.js(12,1): error TS2322: Type 'string |
         // ArrowFunction isn't treated as a this-container
         (args) => {
             this.args = 'hi'
+            ~~~~~~~~~
+!!! error TS2322: Type '"hi"' is not assignable to type 'number'.
             this.newProperty = 1
         }
     }
     var i = new Installer()
-    i.newProperty = i.args // error, number | string =/> number | undefined
-    ~~~~~~~~~~~~~
-!!! error TS2322: Type 'string | number' is not assignable to type 'number | undefined'.
-!!! error TS2322:   Type 'string' is not assignable to type 'number | undefined'.
+    i.newProperty = i.args // ok, number ==> number | undefined
     
\ No newline at end of file
diff --git a/tests/baselines/reference/typeFromPropertyAssignment22.symbols b/tests/baselines/reference/typeFromPropertyAssignment22.symbols
index 2591f0f5a73..1d43e3a4c27 100644
--- a/tests/baselines/reference/typeFromPropertyAssignment22.symbols
+++ b/tests/baselines/reference/typeFromPropertyAssignment22.symbols
@@ -31,7 +31,7 @@ var i = new Installer()
 >i : Symbol(i, Decl(npm-install.js, 10, 3))
 >Installer : Symbol(Installer, Decl(npm-install.js, 0, 0))
 
-i.newProperty = i.args // error, number | string =/> number | undefined
+i.newProperty = i.args // ok, number ==> number | undefined
 >i.newProperty : Symbol(Installer.newProperty, Decl(npm-install.js, 6, 24))
 >i : Symbol(i, Decl(npm-install.js, 10, 3))
 >newProperty : Symbol(Installer.newProperty, Decl(npm-install.js, 6, 24))
diff --git a/tests/baselines/reference/typeFromPropertyAssignment22.types b/tests/baselines/reference/typeFromPropertyAssignment22.types
index 888a9f6efc4..56b1f8c9169 100644
--- a/tests/baselines/reference/typeFromPropertyAssignment22.types
+++ b/tests/baselines/reference/typeFromPropertyAssignment22.types
@@ -26,30 +26,30 @@ Installer.prototype.loadArgMetadata = function (next) {
 
         this.args = 'hi'
 >this.args = 'hi' : "hi"
->this.args : string | number
->this : { args: string | number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
->args : string | number
+>this.args : number
+>this : { args: number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
+>args : number
 >'hi' : "hi"
 
         this.newProperty = 1
 >this.newProperty = 1 : 1
 >this.newProperty : number | undefined
->this : { args: string | number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
+>this : { args: number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
 >newProperty : number | undefined
 >1 : 1
     }
 }
 var i = new Installer()
->i : { args: string | number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
->new Installer() : { args: string | number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
+>i : { args: number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
+>new Installer() : { args: number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
 >Installer : () => void
 
-i.newProperty = i.args // error, number | string =/> number | undefined
->i.newProperty = i.args : string | number
+i.newProperty = i.args // ok, number ==> number | undefined
+>i.newProperty = i.args : number
 >i.newProperty : number | undefined
->i : { args: string | number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
+>i : { args: number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
 >newProperty : number | undefined
->i.args : string | number
->i : { args: string | number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
->args : string | number
+>i.args : number
+>i : { args: number; loadArgMetadata: (next: any) => void; newProperty: number | undefined; }
+>args : number
 
diff --git a/tests/cases/conformance/salsa/inferringClassMembersFromAssignments.ts b/tests/cases/conformance/salsa/inferringClassMembersFromAssignments.ts
index 9cf02a9c7dd..b6c12be6407 100644
--- a/tests/cases/conformance/salsa/inferringClassMembersFromAssignments.ts
+++ b/tests/cases/conformance/salsa/inferringClassMembersFromAssignments.ts
@@ -1,5 +1,7 @@
 // @out: output.js
 // @allowJs: true
+// @checkJs: true
+// @noImplicitAny: true
 // @strictNullChecks: true
 
 // @filename: a.js
@@ -16,11 +18,14 @@ class C {
     method() {
         if (Math.random()) {
             this.inMethod = 0;
+            this.inMethodNullable = null;
         }
         else {
             this.inMethod = "string"
+            this.inMethodNullable = undefined;
         }
         this.inMultiple = "string";
+        this.inMultipleMethods = "string";
 
         var action = () => {
             if (Math.random()) {
@@ -39,6 +44,7 @@ class C {
             this.inGetter = "string"
         }
         this.inMultiple = false;
+        this.inMultipleMethods = false;
     }
     set() {
         if (Math.random()) {
@@ -115,7 +121,12 @@ var stringOrNumberOrUndefined = c.inNestedArrowFunction
 
 var stringOrNumberOrBoolean: string | number | boolean;
 
-var stringOrNumberOrBoolean = c.inMultiple;
+var number: number;
+var number = c.inMultiple;
+var stringOrBooleanOrUndefined : string | boolean | undefined;
+var stringOrBooleanOrUndefined = c.inMultipleMethods;
+var any: any;
+var any = c.inMethodNullable;
 
 
 var stringOrNumberOrUndefined = C.inStaticMethod;
diff --git a/tests/cases/conformance/salsa/typeFromJSConstructor.ts b/tests/cases/conformance/salsa/typeFromJSConstructor.ts
new file mode 100644
index 00000000000..241faec53e2
--- /dev/null
+++ b/tests/cases/conformance/salsa/typeFromJSConstructor.ts
@@ -0,0 +1,36 @@
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+// @strictNullChecks: true
+// @noImplicitAny: true
+// @Filename: a.js
+function Installer () {
+    // arg: number
+    this.arg = 0
+    // unknown: string | boolean | null
+    this.unknown = null
+    // twice: string | undefined
+    this.twice = undefined
+    this.twice = 'hi'
+    // twices: any[] | null
+    this.twices = []
+    this.twices = null
+}
+Installer.prototype.first = function () {
+    this.arg = 'hi' // error
+    this.unknown = 'hi' // ok
+    this.newProperty = 1 // ok: number | boolean
+    this.twice = undefined // ok
+    this.twice = 'hi' // ok
+}
+Installer.prototype.second = function () {
+    this.arg = false // error
+    this.unknown = false // ok
+    this.newProperty = false // ok
+    this.twice = null // error
+    this.twice = false // error
+    this.twices.push(1) // error: Object is possibly null
+    if (this.twices != null) {
+        this.twices.push('hi')
+    }
+}
diff --git a/tests/cases/conformance/salsa/typeFromJSInitializer.ts b/tests/cases/conformance/salsa/typeFromJSInitializer.ts
new file mode 100644
index 00000000000..39d2edb39b3
--- /dev/null
+++ b/tests/cases/conformance/salsa/typeFromJSInitializer.ts
@@ -0,0 +1,59 @@
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+// @strictNullChecks: true
+// @noImplicitAny: true
+// @Filename: a.js
+function A () {
+    // should get any on this-assignments in constructor
+    this.unknown = null
+    this.unknowable = undefined
+    this.empty = []
+}
+var a = new A()
+a.unknown = 1
+a.unknown = true
+a.unknown = {}
+a.unknown = 'hi'
+a.unknowable = 1
+a.unknowable = true
+a.unknowable = {}
+a.unknowable = 'hi'
+a.empty.push(1)
+a.empty.push(true)
+a.empty.push({})
+a.empty.push('hi')
+
+/** @type {number | undefined} */
+var n;
+
+// should get any on parameter initialisers
+function f(a = null, b = n, l = []) {
+    // a should be any
+    a = undefined
+    a = null
+    a = 1
+    a = true
+    a = {}
+    a = 'ok'
+
+    // b should be number | undefined, not any
+    b = 1
+    b = undefined
+    b = 'error'
+
+    // l should be any[]
+    l.push(1)
+    l.push('ok')
+}
+
+// should get any on variable initialisers
+var u = undefined;
+var l = [];
+u = undefined
+u = 1
+u = true
+u = {}
+u = 'ok'
+
+l.push('ok')
diff --git a/tests/cases/conformance/salsa/typeFromPropertyAssignment22.ts b/tests/cases/conformance/salsa/typeFromPropertyAssignment22.ts
index 75bc2c62b90..4f64e611476 100644
--- a/tests/cases/conformance/salsa/typeFromPropertyAssignment22.ts
+++ b/tests/cases/conformance/salsa/typeFromPropertyAssignment22.ts
@@ -14,4 +14,4 @@ Installer.prototype.loadArgMetadata = function (next) {
     }
 }
 var i = new Installer()
-i.newProperty = i.args // error, number | string =/> number | undefined
+i.newProperty = i.args // ok, number ==> number | undefined