Test:this instantiation in type parameters

Make sure that `this` gets instantiated when it's used as a constraint
of a type parameter, and nowhere else in a signature.

tests/baselines/reference/thisTypeInFunctions3.js

@@ -0,0 +1,33 @@
+//// [thisTypeInFunctions3.ts]
+declare class Base {
+    check<TProp extends this>(prop: TProp): boolean;
+}
+
+class Test extends Base {
+    m() {
+        this.check(this);
+    }
+}
+
+
+//// [thisTypeInFunctions3.js]
+var __extends = (this && this.__extends) || (function () {
+    var 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 function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+var Test = /** @class */ (function (_super) {
+    __extends(Test, _super);
+    function Test() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    Test.prototype.m = function () {
+        this.check(this);
+    };
+    return Test;
+}(Base));

tests/baselines/reference/thisTypeInFunctions3.symbols

@@ -0,0 +1,26 @@
+=== tests/cases/conformance/types/thisType/thisTypeInFunctions3.ts ===
+declare class Base {
+>Base : Symbol(Base, Decl(thisTypeInFunctions3.ts, 0, 0))
+
+    check<TProp extends this>(prop: TProp): boolean;
+>check : Symbol(Base.check, Decl(thisTypeInFunctions3.ts, 0, 20))
+>TProp : Symbol(TProp, Decl(thisTypeInFunctions3.ts, 1, 10))
+>prop : Symbol(prop, Decl(thisTypeInFunctions3.ts, 1, 30))
+>TProp : Symbol(TProp, Decl(thisTypeInFunctions3.ts, 1, 10))
+}
+
+class Test extends Base {
+>Test : Symbol(Test, Decl(thisTypeInFunctions3.ts, 2, 1))
+>Base : Symbol(Base, Decl(thisTypeInFunctions3.ts, 0, 0))
+
+    m() {
+>m : Symbol(Test.m, Decl(thisTypeInFunctions3.ts, 4, 25))
+
+        this.check(this);
+>this.check : Symbol(Base.check, Decl(thisTypeInFunctions3.ts, 0, 20))
+>this : Symbol(Test, Decl(thisTypeInFunctions3.ts, 2, 1))
+>check : Symbol(Base.check, Decl(thisTypeInFunctions3.ts, 0, 20))
+>this : Symbol(Test, Decl(thisTypeInFunctions3.ts, 2, 1))
+    }
+}
+

tests/baselines/reference/thisTypeInFunctions3.types

@@ -0,0 +1,27 @@
+=== tests/cases/conformance/types/thisType/thisTypeInFunctions3.ts ===
+declare class Base {
+>Base : Base
+
+    check<TProp extends this>(prop: TProp): boolean;
+>check : <TProp extends this>(prop: TProp) => boolean
+>TProp : TProp
+>prop : TProp
+>TProp : TProp
+}
+
+class Test extends Base {
+>Test : Test
+>Base : Base
+
+    m() {
+>m : () => void
+
+        this.check(this);
+>this.check(this) : boolean
+>this.check : <TProp extends this>(prop: TProp) => boolean
+>this : this
+>check : <TProp extends this>(prop: TProp) => boolean
+>this : this
+    }
+}
+

tests/cases/conformance/types/thisType/thisTypeInFunctions3.ts

@@ -0,0 +1,9 @@
+declare class Base {
+    check<TProp extends this>(prop: TProp): boolean;
+}
+
+class Test extends Base {
+    m() {
+        this.check(this);
+    }
+}