Error on this.xxx access of previously declared but uninitialized property (#38030)

* Error on this.xxx access of previously declared but uninitialized property

* Add tests

* Accept new baselines

src/compiler/checker.ts

@@ -1364,7 +1364,7 @@ namespace ts {
                 return sourceFiles.indexOf(declarationFile) <= sourceFiles.indexOf(useFile);
             }
 
-            if (declaration.pos <= usage.pos) {
+            if (declaration.pos <= usage.pos && !(isPropertyDeclaration(declaration) && isThisProperty(usage.parent) && !declaration.initializer && !declaration.exclamationToken)) {
                 // declaration is before usage
                 if (declaration.kind === SyntaxKind.BindingElement) {
                     // still might be illegal if declaration and usage are both binding elements (eg var [a = b, b = b] = [1, 2])

tests/baselines/reference/abstractPropertyInConstructor.errors.txt

@@ -2,10 +2,11 @@ tests/cases/compiler/abstractPropertyInConstructor.ts(4,24): error TS2715: Abstr
 tests/cases/compiler/abstractPropertyInConstructor.ts(7,18): error TS2715: Abstract property 'prop' in class 'AbstractClass' cannot be accessed in the constructor.
 tests/cases/compiler/abstractPropertyInConstructor.ts(9,14): error TS2715: Abstract property 'cb' in class 'AbstractClass' cannot be accessed in the constructor.
 tests/cases/compiler/abstractPropertyInConstructor.ts(25,18): error TS2715: Abstract property 'prop' in class 'AbstractClass' cannot be accessed in the constructor.
+tests/cases/compiler/abstractPropertyInConstructor.ts(25,18): error TS2729: Property 'prop' is used before its initialization.
 tests/cases/compiler/abstractPropertyInConstructor.ts(39,22): error TS2715: Abstract property 'prop' in class 'AbstractClass' cannot be accessed in the constructor.
 
 
-==== tests/cases/compiler/abstractPropertyInConstructor.ts (5 errors) ====
+==== tests/cases/compiler/abstractPropertyInConstructor.ts (6 errors) ====
     abstract class AbstractClass {
         constructor(str: string, other: AbstractClass) {
             this.method(parseInt(str));
@@ -39,6 +40,9 @@ tests/cases/compiler/abstractPropertyInConstructor.ts(39,22): error TS2715: Abst
         other = this.prop;
                      ~~~~
 !!! error TS2715: Abstract property 'prop' in class 'AbstractClass' cannot be accessed in the constructor.
+                     ~~~~
+!!! error TS2729: Property 'prop' is used before its initialization.
+!!! related TS2728 tests/cases/compiler/abstractPropertyInConstructor.ts:20:14: 'prop' is declared here.
         fn = () => this.prop;
     
         method2() {

tests/baselines/reference/initializerWithThisPropertyAccess.errors.txt

@@ -0,0 +1,44 @@
+tests/cases/compiler/initializerWithThisPropertyAccess.ts(3,14): error TS2729: Property 'a' is used before its initialization.
+tests/cases/compiler/initializerWithThisPropertyAccess.ts(24,29): error TS2729: Property 'bar' is used before its initialization.
+
+
+==== tests/cases/compiler/initializerWithThisPropertyAccess.ts (2 errors) ====
+    class A {
+        a: number;
+        b = this.a;  // Error
+                 ~
+!!! error TS2729: Property 'a' is used before its initialization.
+!!! related TS2728 tests/cases/compiler/initializerWithThisPropertyAccess.ts:2:5: 'a' is declared here.
+        c = () => this.a;
+        d = (new A()).a;
+        constructor() {
+            this.a = 1;
+        }
+    }
+    
+    class B extends A {
+        x = this.a;
+    }
+    
+    class C {
+        a!: number;
+        b = this.a;
+    }
+    
+    // Repro from #37979
+    
+    class Foo {
+        private bar: Bar;
+        readonly barProp = this.bar.prop;
+                                ~~~
+!!! error TS2729: Property 'bar' is used before its initialization.
+!!! related TS2728 tests/cases/compiler/initializerWithThisPropertyAccess.ts:23:13: 'bar' is declared here.
+        constructor() {
+            this.bar = new Bar();
+        }
+    }
+    
+    class Bar {
+        readonly prop = false;
+    }
+    

tests/baselines/reference/initializerWithThisPropertyAccess.js

@@ -0,0 +1,114 @@
+//// [initializerWithThisPropertyAccess.ts]
+class A {
+    a: number;
+    b = this.a;  // Error
+    c = () => this.a;
+    d = (new A()).a;
+    constructor() {
+        this.a = 1;
+    }
+}
+
+class B extends A {
+    x = this.a;
+}
+
+class C {
+    a!: number;
+    b = this.a;
+}
+
+// Repro from #37979
+
+class Foo {
+    private bar: Bar;
+    readonly barProp = this.bar.prop;
+    constructor() {
+        this.bar = new Bar();
+    }
+}
+
+class Bar {
+    readonly prop = false;
+}
+
+
+//// [initializerWithThisPropertyAccess.js]
+"use strict";
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = function (d, b) {
+        extendStatics = Object.setPrototypeOf ||
+            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+            function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
+        return extendStatics(d, b);
+    };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+var A = /** @class */ (function () {
+    function A() {
+        var _this = this;
+        this.b = this.a; // Error
+        this.c = function () { return _this.a; };
+        this.d = (new A()).a;
+        this.a = 1;
+    }
+    return A;
+}());
+var B = /** @class */ (function (_super) {
+    __extends(B, _super);
+    function B() {
+        var _this = _super !== null && _super.apply(this, arguments) || this;
+        _this.x = _this.a;
+        return _this;
+    }
+    return B;
+}(A));
+var C = /** @class */ (function () {
+    function C() {
+        this.b = this.a;
+    }
+    return C;
+}());
+// Repro from #37979
+var Foo = /** @class */ (function () {
+    function Foo() {
+        this.barProp = this.bar.prop;
+        this.bar = new Bar();
+    }
+    return Foo;
+}());
+var Bar = /** @class */ (function () {
+    function Bar() {
+        this.prop = false;
+    }
+    return Bar;
+}());
+
+
+//// [initializerWithThisPropertyAccess.d.ts]
+declare class A {
+    a: number;
+    b: number;
+    c: () => number;
+    d: number;
+    constructor();
+}
+declare class B extends A {
+    x: number;
+}
+declare class C {
+    a: number;
+    b: number;
+}
+declare class Foo {
+    private bar;
+    readonly barProp = false;
+    constructor();
+}
+declare class Bar {
+    readonly prop = false;
+}

tests/baselines/reference/initializerWithThisPropertyAccess.symbols

@@ -0,0 +1,90 @@
+=== tests/cases/compiler/initializerWithThisPropertyAccess.ts ===
+class A {
+>A : Symbol(A, Decl(initializerWithThisPropertyAccess.ts, 0, 0))
+
+    a: number;
+>a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+
+    b = this.a;  // Error
+>b : Symbol(A.b, Decl(initializerWithThisPropertyAccess.ts, 1, 14))
+>this.a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+>this : Symbol(A, Decl(initializerWithThisPropertyAccess.ts, 0, 0))
+>a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+
+    c = () => this.a;
+>c : Symbol(A.c, Decl(initializerWithThisPropertyAccess.ts, 2, 15))
+>this.a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+>this : Symbol(A, Decl(initializerWithThisPropertyAccess.ts, 0, 0))
+>a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+
+    d = (new A()).a;
+>d : Symbol(A.d, Decl(initializerWithThisPropertyAccess.ts, 3, 21))
+>(new A()).a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+>A : Symbol(A, Decl(initializerWithThisPropertyAccess.ts, 0, 0))
+>a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+
+    constructor() {
+        this.a = 1;
+>this.a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+>this : Symbol(A, Decl(initializerWithThisPropertyAccess.ts, 0, 0))
+>a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+    }
+}
+
+class B extends A {
+>B : Symbol(B, Decl(initializerWithThisPropertyAccess.ts, 8, 1))
+>A : Symbol(A, Decl(initializerWithThisPropertyAccess.ts, 0, 0))
+
+    x = this.a;
+>x : Symbol(B.x, Decl(initializerWithThisPropertyAccess.ts, 10, 19))
+>this.a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+>this : Symbol(B, Decl(initializerWithThisPropertyAccess.ts, 8, 1))
+>a : Symbol(A.a, Decl(initializerWithThisPropertyAccess.ts, 0, 9))
+}
+
+class C {
+>C : Symbol(C, Decl(initializerWithThisPropertyAccess.ts, 12, 1))
+
+    a!: number;
+>a : Symbol(C.a, Decl(initializerWithThisPropertyAccess.ts, 14, 9))
+
+    b = this.a;
+>b : Symbol(C.b, Decl(initializerWithThisPropertyAccess.ts, 15, 15))
+>this.a : Symbol(C.a, Decl(initializerWithThisPropertyAccess.ts, 14, 9))
+>this : Symbol(C, Decl(initializerWithThisPropertyAccess.ts, 12, 1))
+>a : Symbol(C.a, Decl(initializerWithThisPropertyAccess.ts, 14, 9))
+}
+
+// Repro from #37979
+
+class Foo {
+>Foo : Symbol(Foo, Decl(initializerWithThisPropertyAccess.ts, 17, 1))
+
+    private bar: Bar;
+>bar : Symbol(Foo.bar, Decl(initializerWithThisPropertyAccess.ts, 21, 11))
+>Bar : Symbol(Bar, Decl(initializerWithThisPropertyAccess.ts, 27, 1))
+
+    readonly barProp = this.bar.prop;
+>barProp : Symbol(Foo.barProp, Decl(initializerWithThisPropertyAccess.ts, 22, 21))
+>this.bar.prop : Symbol(Bar.prop, Decl(initializerWithThisPropertyAccess.ts, 29, 11))
+>this.bar : Symbol(Foo.bar, Decl(initializerWithThisPropertyAccess.ts, 21, 11))
+>this : Symbol(Foo, Decl(initializerWithThisPropertyAccess.ts, 17, 1))
+>bar : Symbol(Foo.bar, Decl(initializerWithThisPropertyAccess.ts, 21, 11))
+>prop : Symbol(Bar.prop, Decl(initializerWithThisPropertyAccess.ts, 29, 11))
+
+    constructor() {
+        this.bar = new Bar();
+>this.bar : Symbol(Foo.bar, Decl(initializerWithThisPropertyAccess.ts, 21, 11))
+>this : Symbol(Foo, Decl(initializerWithThisPropertyAccess.ts, 17, 1))
+>bar : Symbol(Foo.bar, Decl(initializerWithThisPropertyAccess.ts, 21, 11))
+>Bar : Symbol(Bar, Decl(initializerWithThisPropertyAccess.ts, 27, 1))
+    }
+}
+
+class Bar {
+>Bar : Symbol(Bar, Decl(initializerWithThisPropertyAccess.ts, 27, 1))
+
+    readonly prop = false;
+>prop : Symbol(Bar.prop, Decl(initializerWithThisPropertyAccess.ts, 29, 11))
+}
+

tests/baselines/reference/initializerWithThisPropertyAccess.types

@@ -0,0 +1,97 @@
+=== tests/cases/compiler/initializerWithThisPropertyAccess.ts ===
+class A {
+>A : A
+
+    a: number;
+>a : number
+
+    b = this.a;  // Error
+>b : number
+>this.a : number
+>this : this
+>a : number
+
+    c = () => this.a;
+>c : () => number
+>() => this.a : () => number
+>this.a : number
+>this : this
+>a : number
+
+    d = (new A()).a;
+>d : number
+>(new A()).a : number
+>(new A()) : A
+>new A() : A
+>A : typeof A
+>a : number
+
+    constructor() {
+        this.a = 1;
+>this.a = 1 : 1
+>this.a : number
+>this : this
+>a : number
+>1 : 1
+    }
+}
+
+class B extends A {
+>B : B
+>A : A
+
+    x = this.a;
+>x : number
+>this.a : number
+>this : this
+>a : number
+}
+
+class C {
+>C : C
+
+    a!: number;
+>a : number
+
+    b = this.a;
+>b : number
+>this.a : number
+>this : this
+>a : number
+}
+
+// Repro from #37979
+
+class Foo {
+>Foo : Foo
+
+    private bar: Bar;
+>bar : Bar
+
+    readonly barProp = this.bar.prop;
+>barProp : false
+>this.bar.prop : false
+>this.bar : Bar
+>this : this
+>bar : Bar
+>prop : false
+
+    constructor() {
+        this.bar = new Bar();
+>this.bar = new Bar() : Bar
+>this.bar : Bar
+>this : this
+>bar : Bar
+>new Bar() : Bar
+>Bar : typeof Bar
+    }
+}
+
+class Bar {
+>Bar : Bar
+
+    readonly prop = false;
+>prop : false
+>false : false
+}
+

tests/baselines/reference/scopeResolutionIdentifiers.errors.txt

@@ -0,0 +1,45 @@
+tests/cases/conformance/expressions/identifiers/scopeResolutionIdentifiers.ts(24,14): error TS2729: Property 's' is used before its initialization.
+
+
+==== tests/cases/conformance/expressions/identifiers/scopeResolutionIdentifiers.ts (1 errors) ====
+    // EveryType used in a nested scope of a different EveryType with the same name, type of the identifier is the one defined in the inner scope
+    
+    var s: string;
+    module M1 {
+        export var s: number;
+        var n = s;
+        var n: number;
+    }
+    
+    module M2 {
+        var s: number;
+        var n = s;
+        var n: number;
+    }
+    
+    function fn() {
+        var s: boolean;
+        var n = s;
+        var n: boolean;
+    }
+    
+    class C {
+        s: Date;
+        n = this.s;
+                 ~
+!!! error TS2729: Property 's' is used before its initialization.
+!!! related TS2728 tests/cases/conformance/expressions/identifiers/scopeResolutionIdentifiers.ts:23:5: 's' is declared here.
+        x() {
+            var p = this.n;
+            var p: Date;
+        }
+    }
+    
+    module M3 {
+        var s: any;
+        module M4 {
+            var n = s;
+            var n: any;
+        }
+    }
+    

tests/cases/compiler/initializerWithThisPropertyAccess.ts

@@ -0,0 +1,35 @@
+// @strict: true
+// @declaration: true
+
+class A {
+    a: number;
+    b = this.a;  // Error
+    c = () => this.a;
+    d = (new A()).a;
+    constructor() {
+        this.a = 1;
+    }
+}
+
+class B extends A {
+    x = this.a;
+}
+
+class C {
+    a!: number;
+    b = this.a;
+}
+
+// Repro from #37979
+
+class Foo {
+    private bar: Bar;
+    readonly barProp = this.bar.prop;
+    constructor() {
+        this.bar = new Bar();
+    }
+}
+
+class Bar {
+    readonly prop = false;
+}