Infer class properties from methods and not just constructors

src/compiler/binder.ts

@@ -2238,23 +2238,31 @@ namespace ts {
 
         function bindThisPropertyAssignment(node: BinaryExpression) {
             Debug.assert(isInJavaScriptFile(node));
-            // Declare a 'member' if the container is an ES5 class or ES6 constructor
-            if (container.kind === SyntaxKind.FunctionDeclaration || container.kind === SyntaxKind.FunctionExpression) {
-                container.symbol.members = container.symbol.members || createMap<Symbol>();
-                // It's acceptable for multiple 'this' assignments of the same identifier to occur
-                declareSymbol(container.symbol.members, container.symbol, node, SymbolFlags.Property, SymbolFlags.PropertyExcludes & ~SymbolFlags.Property);
-            }
-            else if (container.kind === SyntaxKind.Constructor) {
-                // this.foo assignment in a JavaScript class
-                // Bind this property to the containing class
-                const saveContainer = container;
-                container = container.parent;
-                const symbol = bindPropertyOrMethodOrAccessor(node, SymbolFlags.Property, SymbolFlags.None);
-                if (symbol) {
-                    // constructor-declared symbols can be overwritten by subsequent method declarations
-                    (symbol as Symbol).isReplaceableByMethod = true;
-                }
-                container = saveContainer;
+            switch (container.kind) {
+                case SyntaxKind.FunctionDeclaration:
+                case SyntaxKind.FunctionExpression:
+                    // Declare a 'member' if the container is an ES5 class or ES6 constructor
+                    container.symbol.members = container.symbol.members || createMap<Symbol>();
+                    // It's acceptable for multiple 'this' assignments of the same identifier to occur
+                    declareSymbol(container.symbol.members, container.symbol, node, SymbolFlags.Property, SymbolFlags.PropertyExcludes & ~SymbolFlags.Property);
+                    break;
+
+                case SyntaxKind.Constructor:
+                case SyntaxKind.MethodDeclaration:
+                case SyntaxKind.GetAccessor:
+                case SyntaxKind.SetAccessor:
+                    // this.foo assignment in a JavaScript class
+                    // Bind this property to the containing class
+                    const containingClass = container.parent;
+                    const symbol = hasModifier(container, ModifierFlags.Static)
+                        ? declareSymbol(containingClass.symbol.exports, containingClass.symbol, node, SymbolFlags.Property, SymbolFlags.None)
+                        : declareSymbol(containingClass.symbol.members, containingClass.symbol, node, SymbolFlags.Property, SymbolFlags.None);
+
+                    if (symbol) {
+                        // symbols declared through 'this' property assignements can be overwritten by subsequent method declarations
+                        (symbol as Symbol).isReplaceableByMethod = true;
+                    }
+                    break;
             }
         }
 

src/compiler/checker.ts

@@ -3472,25 +3472,41 @@ namespace ts {
             return undefined;
         }
 
-        // Return the inferred type for a variable, parameter, or property declaration
-        function getTypeForJSSpecialPropertyDeclaration(declaration: Declaration): Type {
-            const expression = declaration.kind === SyntaxKind.BinaryExpression ? <BinaryExpression>declaration :
-                declaration.kind === SyntaxKind.PropertyAccessExpression ? <BinaryExpression>getAncestor(declaration, SyntaxKind.BinaryExpression) :
-                undefined;
+        function getWidendedTypeFromJSSpecialPropetyDeclarations(symbol: Symbol) {
+            const types: Type[] = [];
+            let definedInConstructor = false;
+            let definedInMethod = false;
+            for (const declaration of symbol.declarations) {
+                const expression = declaration.kind === SyntaxKind.BinaryExpression ? <BinaryExpression>declaration :
+                    declaration.kind === SyntaxKind.PropertyAccessExpression ? <BinaryExpression>getAncestor(declaration, SyntaxKind.BinaryExpression) :
+                        undefined;
 
-            if (!expression) {
-                return unknownType;
-            }
-
-            if (expression.flags & NodeFlags.JavaScriptFile) {
-                // If there is a JSDoc type, use it
-                const type = getTypeForDeclarationFromJSDocComment(expression.parent);
-                if (type && type !== unknownType) {
-                    return getWidenedType(type);
+                if (!expression) {
+                    return unknownType;
                 }
+
+                if (isPropertyAccessExpression(expression.left) && expression.left.expression.kind === SyntaxKind.ThisKeyword) {
+                    if (getThisContainer(expression, /*includeArrowFunctions*/ false).kind === SyntaxKind.Constructor) {
+                        definedInConstructor = true;
+                    }
+                    else {
+                        definedInMethod = true;
+                    }
+                }
+
+                if (expression.flags & NodeFlags.JavaScriptFile) {
+                    // If there is a JSDoc type, use it
+                    const type = getTypeForDeclarationFromJSDocComment(expression.parent);
+                    if (type && type !== unknownType) {
+                        types.push(getWidenedType(type));
+                        continue;
+                    }
+                }
+
+                types.push(getWidenedLiteralType(checkExpressionCached(expression.right)));
             }
 
-            return getWidenedLiteralType(checkExpressionCached(expression.right));
+            return getWidenedType(addOptionality(getUnionType(types, /*subtypeReduction*/ true), definedInMethod && !definedInConstructor));
         }
 
         // Return the type implied by a binding pattern element. This is the type of the initializer of the element if
@@ -3647,7 +3663,7 @@ namespace ts {
                 // * className.prototype.method = expr
                 if (declaration.kind === SyntaxKind.BinaryExpression ||
                     declaration.kind === SyntaxKind.PropertyAccessExpression && declaration.parent.kind === SyntaxKind.BinaryExpression) {
-                    type = getWidenedType(getUnionType(map(symbol.declarations, getTypeForJSSpecialPropertyDeclaration), /*subtypeReduction*/ true));
+                    type = getWidendedTypeFromJSSpecialPropetyDeclarations(symbol);
                 }
                 else {
                     type = getWidenedTypeForVariableLikeDeclaration(<VariableLikeDeclaration>declaration, /*reportErrors*/ true);

tests/baselines/reference/inferringClassMembersFromAssignments.js

@@ -0,0 +1,150 @@
+//// [tests/cases/conformance/salsa/inferringClassMembersFromAssignments.ts] ////
+
+//// [a.js]
+
+class C {
+    constructor() {
+        if (Math.random()) {
+            this.inConstructor = 0;
+        }
+        else {
+            this.inConstructor = "string"
+        }
+    }
+    method() {
+        if (Math.random()) {
+            this.inMethod = 0;
+        }
+        else {
+            this.inMethod = "string"
+        }
+    }
+    get() {
+        if (Math.random()) {
+            this.inGetter = 0;
+        }
+        else {
+            this.inGetter = "string"
+        }
+    }
+    set() {
+        if (Math.random()) {
+            this.inSetter = 0;
+        }
+        else {
+            this.inSetter = "string"
+        }
+    }
+    static method() {
+        if (Math.random()) {
+            this.inStaticMethod = 0;
+        }
+        else {
+            this.inStaticMethod = "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"
+        }
+    }
+}
+
+//// [b.ts]
+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.inStaticMethod;
+var stringOrNumberOrUndefined = C.inStaticGetter;
+var stringOrNumberOrUndefined = C.inStaticSetter;
+
+
+//// [output.js]
+var C = (function () {
+    function C() {
+        if (Math.random()) {
+            this.inConstructor = 0;
+        }
+        else {
+            this.inConstructor = "string";
+        }
+    }
+    C.prototype.method = function () {
+        if (Math.random()) {
+            this.inMethod = 0;
+        }
+        else {
+            this.inMethod = "string";
+        }
+    };
+    C.prototype.get = function () {
+        if (Math.random()) {
+            this.inGetter = 0;
+        }
+        else {
+            this.inGetter = "string";
+        }
+    };
+    C.prototype.set = function () {
+        if (Math.random()) {
+            this.inSetter = 0;
+        }
+        else {
+            this.inSetter = "string";
+        }
+    };
+    C.method = function () {
+        if (Math.random()) {
+            this.inStaticMethod = 0;
+        }
+        else {
+            this.inStaticMethod = "string";
+        }
+    };
+    C.get = function () {
+        if (Math.random()) {
+            this.inStaticGetter = 0;
+        }
+        else {
+            this.inStaticGetter = "string";
+        }
+    };
+    C.set = function () {
+        if (Math.random()) {
+            this.inStaticSetter = 0;
+        }
+        else {
+            this.inStaticSetter = "string";
+        }
+    };
+    return C;
+}());
+var c = new C();
+var stringOrNumber;
+var stringOrNumber = c.inConstructor;
+var stringOrNumberOrUndefined;
+var stringOrNumberOrUndefined = c.inMethod;
+var stringOrNumberOrUndefined = c.inGetter;
+var stringOrNumberOrUndefined = c.inSetter;
+var stringOrNumberOrUndefined = C.inStaticMethod;
+var stringOrNumberOrUndefined = C.inStaticGetter;
+var stringOrNumberOrUndefined = C.inStaticSetter;

tests/baselines/reference/inferringClassMembersFromAssignments.symbols

@@ -0,0 +1,198 @@
+=== tests/cases/conformance/salsa/a.js ===
+
+class C {
+>C : Symbol(C, Decl(a.js, 0, 0))
+
+    constructor() {
+        if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+
+            this.inConstructor = 0;
+>this.inConstructor : Symbol(C.inConstructor, Decl(a.js, 3, 28), Decl(a.js, 6, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inConstructor : Symbol(C.inConstructor, Decl(a.js, 3, 28), Decl(a.js, 6, 14))
+        }
+        else {
+            this.inConstructor = "string"
+>this.inConstructor : Symbol(C.inConstructor, Decl(a.js, 3, 28), Decl(a.js, 6, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inConstructor : Symbol(C.inConstructor, Decl(a.js, 3, 28), Decl(a.js, 6, 14))
+        }
+    }
+    method() {
+>method : Symbol(C.method, Decl(a.js, 9, 5))
+
+        if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>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 : Symbol(C, Decl(a.js, 0, 0))
+>inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 14))
+        }
+        else {
+            this.inMethod = "string"
+>this.inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 14))
+        }
+    }
+    get() {
+>get : Symbol(C.get, Decl(a.js, 17, 5))
+
+        if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+
+            this.inGetter = 0;
+>this.inGetter : Symbol(C.inGetter, Decl(a.js, 19, 28), Decl(a.js, 22, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inGetter : Symbol(C.inGetter, Decl(a.js, 19, 28), Decl(a.js, 22, 14))
+        }
+        else {
+            this.inGetter = "string"
+>this.inGetter : Symbol(C.inGetter, Decl(a.js, 19, 28), Decl(a.js, 22, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inGetter : Symbol(C.inGetter, Decl(a.js, 19, 28), Decl(a.js, 22, 14))
+        }
+    }
+    set() {
+>set : Symbol(C.set, Decl(a.js, 25, 5))
+
+        if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+
+            this.inSetter = 0;
+>this.inSetter : Symbol(C.inSetter, Decl(a.js, 27, 28), Decl(a.js, 30, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inSetter : Symbol(C.inSetter, Decl(a.js, 27, 28), Decl(a.js, 30, 14))
+        }
+        else {
+            this.inSetter = "string"
+>this.inSetter : Symbol(C.inSetter, Decl(a.js, 27, 28), Decl(a.js, 30, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inSetter : Symbol(C.inSetter, Decl(a.js, 27, 28), Decl(a.js, 30, 14))
+        }
+    }
+    static method() {
+>method : Symbol(C.method, Decl(a.js, 33, 5))
+
+        if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+
+            this.inStaticMethod = 0;
+>this.inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 35, 28), Decl(a.js, 38, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 35, 28), Decl(a.js, 38, 14))
+        }
+        else {
+            this.inStaticMethod = "string"
+>this.inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 35, 28), Decl(a.js, 38, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 35, 28), Decl(a.js, 38, 14))
+        }
+    }
+    static get() {
+>get : Symbol(C.get, Decl(a.js, 41, 5))
+
+        if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+
+            this.inStaticGetter = 0;
+>this.inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 43, 28), Decl(a.js, 46, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 43, 28), Decl(a.js, 46, 14))
+        }
+        else {
+            this.inStaticGetter = "string"
+>this.inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 43, 28), Decl(a.js, 46, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 43, 28), Decl(a.js, 46, 14))
+        }
+    }
+    static set() {
+>set : Symbol(C.set, Decl(a.js, 49, 5))
+
+        if (Math.random()) {
+>Math.random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+>Math : Symbol(Math, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>random : Symbol(Math.random, Decl(lib.d.ts, --, --))
+
+            this.inStaticSetter = 0;
+>this.inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 51, 28), Decl(a.js, 54, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 51, 28), Decl(a.js, 54, 14))
+        }
+        else {
+            this.inStaticSetter = "string"
+>this.inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 51, 28), Decl(a.js, 54, 14))
+>this : Symbol(C, Decl(a.js, 0, 0))
+>inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 51, 28), Decl(a.js, 54, 14))
+        }
+    }
+}
+
+=== tests/cases/conformance/salsa/b.ts ===
+var c = new C();
+>c : Symbol(c, Decl(b.ts, 0, 3))
+>C : Symbol(C, Decl(a.js, 0, 0))
+
+var stringOrNumber: string | number;
+>stringOrNumber : Symbol(stringOrNumber, Decl(b.ts, 2, 3), Decl(b.ts, 3, 3))
+
+var stringOrNumber = c.inConstructor;
+>stringOrNumber : Symbol(stringOrNumber, Decl(b.ts, 2, 3), Decl(b.ts, 3, 3))
+>c.inConstructor : Symbol(C.inConstructor, Decl(a.js, 3, 28), Decl(a.js, 6, 14))
+>c : Symbol(c, Decl(b.ts, 0, 3))
+>inConstructor : Symbol(C.inConstructor, Decl(a.js, 3, 28), Decl(a.js, 6, 14))
+
+var stringOrNumberOrUndefined: string | number | undefined;
+>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, 11, 3), Decl(b.ts, 12, 3), Decl(b.ts, 13, 3))
+
+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, 11, 3), Decl(b.ts, 12, 3), Decl(b.ts, 13, 3))
+>c.inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 14))
+>c : Symbol(c, Decl(b.ts, 0, 3))
+>inMethod : Symbol(C.inMethod, Decl(a.js, 11, 28), Decl(a.js, 14, 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, 11, 3), Decl(b.ts, 12, 3), Decl(b.ts, 13, 3))
+>c.inGetter : Symbol(C.inGetter, Decl(a.js, 19, 28), Decl(a.js, 22, 14))
+>c : Symbol(c, Decl(b.ts, 0, 3))
+>inGetter : Symbol(C.inGetter, Decl(a.js, 19, 28), Decl(a.js, 22, 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, 11, 3), Decl(b.ts, 12, 3), Decl(b.ts, 13, 3))
+>c.inSetter : Symbol(C.inSetter, Decl(a.js, 27, 28), Decl(a.js, 30, 14))
+>c : Symbol(c, Decl(b.ts, 0, 3))
+>inSetter : Symbol(C.inSetter, Decl(a.js, 27, 28), Decl(a.js, 30, 14))
+
+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, 11, 3), Decl(b.ts, 12, 3), Decl(b.ts, 13, 3))
+>C.inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 35, 28), Decl(a.js, 38, 14))
+>C : Symbol(C, Decl(a.js, 0, 0))
+>inStaticMethod : Symbol(C.inStaticMethod, Decl(a.js, 35, 28), Decl(a.js, 38, 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, 11, 3), Decl(b.ts, 12, 3), Decl(b.ts, 13, 3))
+>C.inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 43, 28), Decl(a.js, 46, 14))
+>C : Symbol(C, Decl(a.js, 0, 0))
+>inStaticGetter : Symbol(C.inStaticGetter, Decl(a.js, 43, 28), Decl(a.js, 46, 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, 11, 3), Decl(b.ts, 12, 3), Decl(b.ts, 13, 3))
+>C.inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 51, 28), Decl(a.js, 54, 14))
+>C : Symbol(C, Decl(a.js, 0, 0))
+>inStaticSetter : Symbol(C.inStaticSetter, Decl(a.js, 51, 28), Decl(a.js, 54, 14))
+

tests/baselines/reference/inferringClassMembersFromAssignments.types

@@ -0,0 +1,234 @@
+=== tests/cases/conformance/salsa/a.js ===
+
+class C {
+>C : C
+
+    constructor() {
+        if (Math.random()) {
+>Math.random() : number
+>Math.random : () => number
+>Math : Math
+>random : () => number
+
+            this.inConstructor = 0;
+>this.inConstructor = 0 : 0
+>this.inConstructor : string | number
+>this : this
+>inConstructor : string | number
+>0 : 0
+        }
+        else {
+            this.inConstructor = "string"
+>this.inConstructor = "string" : "string"
+>this.inConstructor : string | number
+>this : this
+>inConstructor : string | number
+>"string" : "string"
+        }
+    }
+    method() {
+>method : () => void
+
+        if (Math.random()) {
+>Math.random() : number
+>Math.random : () => number
+>Math : Math
+>random : () => number
+
+            this.inMethod = 0;
+>this.inMethod = 0 : 0
+>this.inMethod : string | number | undefined
+>this : this
+>inMethod : string | number | undefined
+>0 : 0
+        }
+        else {
+            this.inMethod = "string"
+>this.inMethod = "string" : "string"
+>this.inMethod : string | number | undefined
+>this : this
+>inMethod : string | number | undefined
+>"string" : "string"
+        }
+    }
+    get() {
+>get : () => void
+
+        if (Math.random()) {
+>Math.random() : number
+>Math.random : () => number
+>Math : Math
+>random : () => number
+
+            this.inGetter = 0;
+>this.inGetter = 0 : 0
+>this.inGetter : string | number | undefined
+>this : this
+>inGetter : string | number | undefined
+>0 : 0
+        }
+        else {
+            this.inGetter = "string"
+>this.inGetter = "string" : "string"
+>this.inGetter : string | number | undefined
+>this : this
+>inGetter : string | number | undefined
+>"string" : "string"
+        }
+    }
+    set() {
+>set : () => void
+
+        if (Math.random()) {
+>Math.random() : number
+>Math.random : () => number
+>Math : Math
+>random : () => number
+
+            this.inSetter = 0;
+>this.inSetter = 0 : 0
+>this.inSetter : string | number | undefined
+>this : this
+>inSetter : string | number | undefined
+>0 : 0
+        }
+        else {
+            this.inSetter = "string"
+>this.inSetter = "string" : "string"
+>this.inSetter : string | number | undefined
+>this : this
+>inSetter : string | number | undefined
+>"string" : "string"
+        }
+    }
+    static method() {
+>method : () => void
+
+        if (Math.random()) {
+>Math.random() : number
+>Math.random : () => number
+>Math : Math
+>random : () => number
+
+            this.inStaticMethod = 0;
+>this.inStaticMethod = 0 : 0
+>this.inStaticMethod : string | number | undefined
+>this : typeof C
+>inStaticMethod : string | number | undefined
+>0 : 0
+        }
+        else {
+            this.inStaticMethod = "string"
+>this.inStaticMethod = "string" : "string"
+>this.inStaticMethod : string | number | undefined
+>this : typeof C
+>inStaticMethod : string | number | undefined
+>"string" : "string"
+        }
+    }
+    static get() {
+>get : () => void
+
+        if (Math.random()) {
+>Math.random() : number
+>Math.random : () => number
+>Math : Math
+>random : () => number
+
+            this.inStaticGetter = 0;
+>this.inStaticGetter = 0 : 0
+>this.inStaticGetter : string | number | undefined
+>this : typeof C
+>inStaticGetter : string | number | undefined
+>0 : 0
+        }
+        else {
+            this.inStaticGetter = "string"
+>this.inStaticGetter = "string" : "string"
+>this.inStaticGetter : string | number | undefined
+>this : typeof C
+>inStaticGetter : string | number | undefined
+>"string" : "string"
+        }
+    }
+    static set() {
+>set : () => void
+
+        if (Math.random()) {
+>Math.random() : number
+>Math.random : () => number
+>Math : Math
+>random : () => number
+
+            this.inStaticSetter = 0;
+>this.inStaticSetter = 0 : 0
+>this.inStaticSetter : string | number | undefined
+>this : typeof C
+>inStaticSetter : string | number | undefined
+>0 : 0
+        }
+        else {
+            this.inStaticSetter = "string"
+>this.inStaticSetter = "string" : "string"
+>this.inStaticSetter : string | number | undefined
+>this : typeof C
+>inStaticSetter : string | number | undefined
+>"string" : "string"
+        }
+    }
+}
+
+=== tests/cases/conformance/salsa/b.ts ===
+var c = new C();
+>c : C
+>new C() : C
+>C : typeof C
+
+var stringOrNumber: string | number;
+>stringOrNumber : string | number
+
+var stringOrNumber = c.inConstructor;
+>stringOrNumber : string | number
+>c.inConstructor : string | number
+>c : C
+>inConstructor : string | number
+
+var stringOrNumberOrUndefined: string | number | undefined;
+>stringOrNumberOrUndefined : string | number | undefined
+
+var stringOrNumberOrUndefined = c.inMethod;
+>stringOrNumberOrUndefined : string | number | undefined
+>c.inMethod : string | number | undefined
+>c : C
+>inMethod : string | number | undefined
+
+var stringOrNumberOrUndefined = c.inGetter;
+>stringOrNumberOrUndefined : string | number | undefined
+>c.inGetter : string | number | undefined
+>c : C
+>inGetter : string | number | undefined
+
+var stringOrNumberOrUndefined = c.inSetter;
+>stringOrNumberOrUndefined : string | number | undefined
+>c.inSetter : string | number | undefined
+>c : C
+>inSetter : string | number | undefined
+
+var stringOrNumberOrUndefined = C.inStaticMethod;
+>stringOrNumberOrUndefined : string | number | undefined
+>C.inStaticMethod : string | number | undefined
+>C : typeof C
+>inStaticMethod : string | number | undefined
+
+var stringOrNumberOrUndefined = C.inStaticGetter;
+>stringOrNumberOrUndefined : string | number | undefined
+>C.inStaticGetter : string | number | undefined
+>C : typeof C
+>inStaticGetter : string | number | undefined
+
+var stringOrNumberOrUndefined = C.inStaticSetter;
+>stringOrNumberOrUndefined : string | number | undefined
+>C.inStaticSetter : string | number | undefined
+>C : typeof C
+>inStaticSetter : string | number | undefined
+

tests/cases/conformance/salsa/inferringClassMembersFromAssignments.ts

@@ -0,0 +1,79 @@
+// @out: output.js
+// @allowJs: true
+// @strictNullChecks: true
+
+// @filename: a.js
+class C {
+    constructor() {
+        if (Math.random()) {
+            this.inConstructor = 0;
+        }
+        else {
+            this.inConstructor = "string"
+        }
+    }
+    method() {
+        if (Math.random()) {
+            this.inMethod = 0;
+        }
+        else {
+            this.inMethod = "string"
+        }
+    }
+    get() {
+        if (Math.random()) {
+            this.inGetter = 0;
+        }
+        else {
+            this.inGetter = "string"
+        }
+    }
+    set() {
+        if (Math.random()) {
+            this.inSetter = 0;
+        }
+        else {
+            this.inSetter = "string"
+        }
+    }
+    static method() {
+        if (Math.random()) {
+            this.inStaticMethod = 0;
+        }
+        else {
+            this.inStaticMethod = "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"
+        }
+    }
+}
+
+// @filename: b.ts
+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.inStaticMethod;
+var stringOrNumberOrUndefined = C.inStaticGetter;
+var stringOrNumberOrUndefined = C.inStaticSetter;