diff --git a/README.md b/README.md
index 3200498b0cf..68b589efcce 100644
--- a/README.md
+++ b/README.md
@@ -61,29 +61,29 @@ Change to the TypeScript directory:
 cd TypeScript
 ```
 
-Install Gulp tools and dev dependencies:
+Install Jake tools and dev dependencies:
 
 ```bash
-npm install -g gulp
+npm install -g jake
 npm install
 ```
 
 Use one of the following to build and test:
 
 ```
-gulp local            # Build the compiler into built/local 
-gulp clean            # Delete the built compiler 
-gulp LKG              # Replace the last known good with the built one.
+jake local            # Build the compiler into built/local 
+jake clean            # Delete the built compiler 
+jake LKG              # Replace the last known good with the built one.
                       # Bootstrapping step to be executed when the built compiler reaches a stable state.
-gulp tests            # Build the test infrastructure using the built compiler. 
-gulp runtests         # Run tests using the built compiler and test infrastructure. 
+jake tests            # Build the test infrastructure using the built compiler. 
+jake runtests         # Run tests using the built compiler and test infrastructure. 
                       # You can override the host or specify a test for this command. 
                       # Use host=<hostName> or tests=<testPath>. 
-gulp runtests-browser # Runs the tests using the built run.js file. Syntax is gulp runtests. Optional
+jake runtests-browser # Runs the tests using the built run.js file. Syntax is jake runtests. Optional
                         parameters 'host=', 'tests=[regex], reporter=[list|spec|json|<more>]'.
-gulp baseline-accept  # This replaces the baseline test results with the results obtained from gulp runtests.
-gulp lint             # Runs tslint on the TypeScript source.
-gulp help             # List the above commands. 
+jake baseline-accept  # This replaces the baseline test results with the results obtained from jake runtests.
+jake lint             # Runs tslint on the TypeScript source.
+jake help             # List the above commands. 
 ```
 
 
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 1e38d2d645c..ae21da9c9d0 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -17122,20 +17122,28 @@ namespace ts {
 
             // Find the first enclosing class that has the declaring classes of the protected constituents
             // of the property as base classes
-            const enclosingClass = forEachEnclosingClass(node, enclosingDeclaration => {
+            let enclosingClass = forEachEnclosingClass(node, enclosingDeclaration => {
                 const enclosingClass = <InterfaceType>getDeclaredTypeOfSymbol(getSymbolOfNode(enclosingDeclaration)!);
                 return isClassDerivedFromDeclaringClasses(enclosingClass, prop) ? enclosingClass : undefined;
             });
             // A protected property is accessible if the property is within the declaring class or classes derived from it
             if (!enclosingClass) {
-                error(errorNode, Diagnostics.Property_0_is_protected_and_only_accessible_within_class_1_and_its_subclasses, symbolToString(prop), typeToString(getDeclaringClass(prop) || type));
-                return false;
+                // allow PropertyAccessibility if context is in function with this parameter
+                // static member access is disallow
+                let thisParameter: ParameterDeclaration | undefined;
+                if (flags & ModifierFlags.Static || !(thisParameter = getThisParameterFromNodeContext(node)) || !thisParameter.type) {
+                    error(errorNode, Diagnostics.Property_0_is_protected_and_only_accessible_within_class_1_and_its_subclasses, symbolToString(prop), typeToString(getDeclaringClass(prop) || type));
+                    return false;
+                }
+
+                const thisType = getTypeFromTypeNode(thisParameter.type);
+                enclosingClass = ((thisType.flags & TypeFlags.TypeParameter) ? getConstraintFromTypeParameter(<TypeParameter>thisType) : thisType) as InterfaceType;
             }
             // No further restrictions for static properties
             if (flags & ModifierFlags.Static) {
                 return true;
             }
-             if (type.flags & TypeFlags.TypeParameter) {
+            if (type.flags & TypeFlags.TypeParameter) {
                 // get the original type -- represented as the type constraint of the 'this' type
                 type = (type as TypeParameter).isThisType ? getConstraintOfTypeParameter(<TypeParameter>type)! : getBaseConstraintOfType(<TypeParameter>type)!; // TODO: GH#18217 Use a different variable that's allowed to be undefined
             }
@@ -17146,6 +17154,11 @@ namespace ts {
             return true;
         }
 
+        function getThisParameterFromNodeContext (node: Node) {
+            const thisContainer = getThisContainer(node, /* includeArrowFunctions */ false);
+            return thisContainer && isFunctionLike(thisContainer) ? getThisParameter(thisContainer) : undefined;
+        }
+
         function symbolHasNonMethodDeclaration(symbol: Symbol) {
             return forEachProperty(symbol, prop => {
                 const propKind = getDeclarationKindFromSymbol(prop);
diff --git a/src/server/session.ts b/src/server/session.ts
index 8ec6d357423..88980367e84 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -511,6 +511,8 @@ namespace ts.server {
 
                 const { fileName, project } = checkList[index];
                 index++;
+                // Ensure the project is upto date before checking if this file is present in the project
+                project.updateGraph();
                 if (!project.containsFile(fileName, requireOpen)) {
                     return;
                 }
diff --git a/src/testRunner/unittests/tsserverProjectSystem.ts b/src/testRunner/unittests/tsserverProjectSystem.ts
index f48f59c6970..04720fe42af 100644
--- a/src/testRunner/unittests/tsserverProjectSystem.ts
+++ b/src/testRunner/unittests/tsserverProjectSystem.ts
@@ -58,6 +58,18 @@ namespace ts.projectSystem {
         getLogFileName: () => undefined,
     };
 
+    function createHasErrorMessageLogger() {
+        let hasErrorMsg = false;
+        const { close, hasLevel, loggingEnabled, startGroup, endGroup, info, getLogFileName, perftrc } = nullLogger;
+        const logger: server.Logger = {
+            close, hasLevel, loggingEnabled, startGroup, endGroup, info, getLogFileName, perftrc,
+            msg: () => {
+                hasErrorMsg = true;
+            }
+        };
+        return { logger, hasErrorMsg: () => hasErrorMsg };
+    }
+
     export class TestTypingsInstaller extends TI.TypingsInstaller implements server.ITypingsInstaller {
         protected projectService: server.ProjectService;
         constructor(
@@ -2913,14 +2925,7 @@ namespace ts.projectSystem {
         });
 
         it("Getting errors from closed script info does not throw exception (because of getting project from orphan script info)", () => {
-            let hasErrorMsg = false;
-            const { close, hasLevel, loggingEnabled, startGroup, endGroup, info, getLogFileName, perftrc } = nullLogger;
-            const logger: server.Logger = {
-                close, hasLevel, loggingEnabled, startGroup, endGroup, info, getLogFileName, perftrc,
-                msg: () => {
-                    hasErrorMsg = true;
-                }
-            };
+            const { logger, hasErrorMsg } = createHasErrorMessageLogger();
             const f1 = {
                 path: "/a/b/app.ts",
                 content: "let x = 1;"
@@ -2950,7 +2955,7 @@ namespace ts.projectSystem {
                     files: [f1.path]
                 }
             });
-            assert.isFalse(hasErrorMsg);
+            assert.isFalse(hasErrorMsg());
         });
 
         it("Changed module resolution reflected when specifying files list", () => {
@@ -3316,6 +3321,129 @@ namespace ts.projectSystem {
                 assert.equal(info.containingProjects.length, 0);
             }
         });
+
+        it("handles delayed directory watch invoke on file creation", () => {
+            const projectRootPath = "/users/username/projects/project";
+            const fileB: File = {
+                path: `${projectRootPath}/b.ts`,
+                content: "export const b = 10;"
+            };
+            const fileA: File = {
+                path: `${projectRootPath}/a.ts`,
+                content: "export const a = 10;"
+            };
+            const fileSubA: File = {
+                path: `${projectRootPath}/sub/a.ts`,
+                content: fileA.content
+            };
+            const config: File = {
+                path: `${projectRootPath}/tsconfig.json`,
+                content: "{}"
+            };
+            const files = [fileSubA, fileB, config, libFile];
+            const host = createServerHost(files);
+            const { logger, hasErrorMsg } = createHasErrorMessageLogger();
+            const session = createSession(host, { canUseEvents: true, noGetErrOnBackgroundUpdate: true, logger });
+            openFile(fileB);
+            openFile(fileSubA);
+
+            const services = session.getProjectService();
+            checkNumberOfProjects(services, { configuredProjects: 1 });
+            checkProjectActualFiles(services.configuredProjects.get(config.path)!, files.map(f => f.path));
+            host.checkTimeoutQueueLengthAndRun(0);
+
+            // This should schedule 2 timeouts for ensuring project structure and ensuring projects for open file
+            const filesWithFileA = files.map(f => f === fileSubA ? fileA : f);
+            host.reloadFS(files.map(f => f === fileSubA ? fileA : f));
+            host.checkTimeoutQueueLength(2);
+
+            closeFile(fileSubA);
+            // This should cancel existing updates and schedule new ones
+            host.checkTimeoutQueueLength(2);
+            checkNumberOfProjects(services, { configuredProjects: 1 });
+            checkProjectActualFiles(services.configuredProjects.get(config.path)!, files.map(f => f.path));
+
+            // Open the fileA (as if rename)
+            openFile(fileA);
+
+            // config project is updated to check if fileA is present in it
+            checkNumberOfProjects(services, { configuredProjects: 1 });
+            checkProjectActualFiles(services.configuredProjects.get(config.path)!, filesWithFileA.map(f => f.path));
+
+            // Run the timeout for updating configured project and ensuring projects for open file
+            host.checkTimeoutQueueLengthAndRun(2);
+            checkProjectActualFiles(services.configuredProjects.get(config.path)!, filesWithFileA.map(f => f.path));
+
+            // file is deleted but watches are not yet invoked
+            const originalFileExists = host.fileExists;
+            host.fileExists = s => s === fileA.path ? false : originalFileExists.call(host, s);
+            closeFile(fileA);
+            host.checkTimeoutQueueLength(2); // Update configured project and projects for open file
+            checkProjectActualFiles(services.configuredProjects.get(config.path)!, filesWithFileA.map(f => f.path));
+
+           // host.fileExists = originalFileExists;
+            openFile(fileSubA);
+            // This should create inferred project since fileSubA not on the disk
+            checkProjectActualFiles(services.configuredProjects.get(config.path)!, mapDefined(filesWithFileA, f => f === fileA ? undefined : f.path));
+            checkProjectActualFiles(services.inferredProjects[0], [fileSubA.path, libFile.path]);
+
+            host.checkTimeoutQueueLengthAndRun(2); // Update configured project and projects for open file
+            host.fileExists = originalFileExists;
+
+            // Actually trigger the file move
+            host.reloadFS(files);
+            host.checkTimeoutQueueLength(2);
+            const fileBErrorTimeoutId = host.getNextTimeoutId();
+
+            session.executeCommandSeq<protocol.GeterrRequest>({
+                command: protocol.CommandTypes.Geterr,
+                arguments: {
+                    files: [fileB.path, fileSubA.path],
+                    delay: 0
+                }
+            });
+            const getErrSeqId = session.getSeq();
+            host.checkTimeoutQueueLength(3);
+
+            session.clearMessages();
+            host.runQueuedTimeoutCallbacks(fileBErrorTimeoutId);
+            checkErrorMessage(session, "syntaxDiag", { file: fileB.path, diagnostics: [] });
+
+            session.clearMessages();
+            host.runQueuedImmediateCallbacks();
+            checkErrorMessage(session, "semanticDiag", { file: fileB.path, diagnostics: [] });
+
+            session.clearMessages();
+            const fileSubAErrorTimeoutId = host.getNextTimeoutId();
+            host.runQueuedImmediateCallbacks();
+            checkErrorMessage(session, "suggestionDiag", { file: fileB.path, diagnostics: [] });
+
+            session.clearMessages();
+            host.checkTimeoutQueueLength(3);
+            host.runQueuedTimeoutCallbacks(fileSubAErrorTimeoutId);
+            checkCompleteEvent(session, 1, getErrSeqId);
+            assert.isFalse(hasErrorMsg());
+
+            function openFile(file: File) {
+                session.executeCommandSeq<protocol.OpenRequest>({
+                    command: protocol.CommandTypes.Open,
+                    arguments: {
+                        file: file.path,
+                        fileContent: file.content,
+                        projectRootPath
+                    }
+                });
+            }
+
+            function closeFile(file: File) {
+                session.executeCommandSeq<protocol.CloseRequest>({
+                    command: protocol.CommandTypes.Close,
+                    arguments: {
+                        file: file.path
+                    }
+                });
+            }
+        });
     });
 
     describe("tsserverProjectSystem Proper errors", () => {
diff --git a/tests/baselines/reference/thisTypeAccessibility.errors.txt b/tests/baselines/reference/thisTypeAccessibility.errors.txt
new file mode 100644
index 00000000000..915d6f20b82
--- /dev/null
+++ b/tests/baselines/reference/thisTypeAccessibility.errors.txt
@@ -0,0 +1,74 @@
+tests/cases/conformance/types/thisType/thisTypeAccessibility.ts(17,10): error TS2341: Property 'p' is private and only accessible within class 'MyClass'.
+tests/cases/conformance/types/thisType/thisTypeAccessibility.ts(20,13): error TS2341: Property 'sp' is private and only accessible within class 'MyClass'.
+tests/cases/conformance/types/thisType/thisTypeAccessibility.ts(21,13): error TS2445: Property 'spp' is protected and only accessible within class 'MyClass' and its subclasses.
+tests/cases/conformance/types/thisType/thisTypeAccessibility.ts(26,10): error TS2341: Property 'p' is private and only accessible within class 'MyClass'.
+tests/cases/conformance/types/thisType/thisTypeAccessibility.ts(29,13): error TS2341: Property 'sp' is private and only accessible within class 'MyClass'.
+tests/cases/conformance/types/thisType/thisTypeAccessibility.ts(30,13): error TS2445: Property 'spp' is protected and only accessible within class 'MyClass' and its subclasses.
+tests/cases/conformance/types/thisType/thisTypeAccessibility.ts(35,10): error TS2341: Property 'p' is private and only accessible within class 'MyClass'.
+tests/cases/conformance/types/thisType/thisTypeAccessibility.ts(38,13): error TS2341: Property 'sp' is private and only accessible within class 'MyClass'.
+tests/cases/conformance/types/thisType/thisTypeAccessibility.ts(39,13): error TS2445: Property 'spp' is protected and only accessible within class 'MyClass' and its subclasses.
+
+
+==== tests/cases/conformance/types/thisType/thisTypeAccessibility.ts (9 errors) ====
+    class MyClass {
+        private p: number = 123;
+        protected pp: number = 123;
+        public ppp: number = 123;
+        private static sp: number = 123;
+        protected static spp: number = 123;
+        public static sppp: number = 123;
+    }
+    
+    interface MyClass {
+        extension1(p: number): void;
+        extension2(p: number): void;
+        extension3(p: number): void;
+    }
+    
+    MyClass.prototype.extension1 = function (this: MyClass, p: number) { 
+        this.p = p;
+             ~
+!!! error TS2341: Property 'p' is private and only accessible within class 'MyClass'.
+        this.pp = p;
+        this.ppp = p;
+        MyClass.sp = p;
+                ~~
+!!! error TS2341: Property 'sp' is private and only accessible within class 'MyClass'.
+        MyClass.spp = p;
+                ~~~
+!!! error TS2445: Property 'spp' is protected and only accessible within class 'MyClass' and its subclasses.
+        MyClass.sppp = p;
+    }
+    
+    MyClass.prototype.extension2 = function<T extends MyClass> (this: T, p: number) { 
+        this.p = p;
+             ~
+!!! error TS2341: Property 'p' is private and only accessible within class 'MyClass'.
+        this.pp = p;
+        this.ppp = p;
+        MyClass.sp = p;
+                ~~
+!!! error TS2341: Property 'sp' is private and only accessible within class 'MyClass'.
+        MyClass.spp = p;
+                ~~~
+!!! error TS2445: Property 'spp' is protected and only accessible within class 'MyClass' and its subclasses.
+        MyClass.sppp = p;
+    }
+    
+    function extension3<T extends MyClass> (this: T, p: number) { 
+        this.p = p;
+             ~
+!!! error TS2341: Property 'p' is private and only accessible within class 'MyClass'.
+        this.pp = p;
+        this.ppp = p;
+        MyClass.sp = p;
+                ~~
+!!! error TS2341: Property 'sp' is private and only accessible within class 'MyClass'.
+        MyClass.spp = p;
+                ~~~
+!!! error TS2445: Property 'spp' is protected and only accessible within class 'MyClass' and its subclasses.
+        MyClass.sppp = p;
+    }
+    
+    MyClass.prototype.extension3 = extension3;
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/thisTypeAccessibility.js b/tests/baselines/reference/thisTypeAccessibility.js
new file mode 100644
index 00000000000..04340cebcd3
--- /dev/null
+++ b/tests/baselines/reference/thisTypeAccessibility.js
@@ -0,0 +1,83 @@
+//// [thisTypeAccessibility.ts]
+class MyClass {
+    private p: number = 123;
+    protected pp: number = 123;
+    public ppp: number = 123;
+    private static sp: number = 123;
+    protected static spp: number = 123;
+    public static sppp: number = 123;
+}
+
+interface MyClass {
+    extension1(p: number): void;
+    extension2(p: number): void;
+    extension3(p: number): void;
+}
+
+MyClass.prototype.extension1 = function (this: MyClass, p: number) { 
+    this.p = p;
+    this.pp = p;
+    this.ppp = p;
+    MyClass.sp = p;
+    MyClass.spp = p;
+    MyClass.sppp = p;
+}
+
+MyClass.prototype.extension2 = function<T extends MyClass> (this: T, p: number) { 
+    this.p = p;
+    this.pp = p;
+    this.ppp = p;
+    MyClass.sp = p;
+    MyClass.spp = p;
+    MyClass.sppp = p;
+}
+
+function extension3<T extends MyClass> (this: T, p: number) { 
+    this.p = p;
+    this.pp = p;
+    this.ppp = p;
+    MyClass.sp = p;
+    MyClass.spp = p;
+    MyClass.sppp = p;
+}
+
+MyClass.prototype.extension3 = extension3;
+
+
+//// [thisTypeAccessibility.js]
+var MyClass = /** @class */ (function () {
+    function MyClass() {
+        this.p = 123;
+        this.pp = 123;
+        this.ppp = 123;
+    }
+    MyClass.sp = 123;
+    MyClass.spp = 123;
+    MyClass.sppp = 123;
+    return MyClass;
+}());
+MyClass.prototype.extension1 = function (p) {
+    this.p = p;
+    this.pp = p;
+    this.ppp = p;
+    MyClass.sp = p;
+    MyClass.spp = p;
+    MyClass.sppp = p;
+};
+MyClass.prototype.extension2 = function (p) {
+    this.p = p;
+    this.pp = p;
+    this.ppp = p;
+    MyClass.sp = p;
+    MyClass.spp = p;
+    MyClass.sppp = p;
+};
+function extension3(p) {
+    this.p = p;
+    this.pp = p;
+    this.ppp = p;
+    MyClass.sp = p;
+    MyClass.spp = p;
+    MyClass.sppp = p;
+}
+MyClass.prototype.extension3 = extension3;
diff --git a/tests/baselines/reference/thisTypeAccessibility.symbols b/tests/baselines/reference/thisTypeAccessibility.symbols
new file mode 100644
index 00000000000..bbb62fa57bc
--- /dev/null
+++ b/tests/baselines/reference/thisTypeAccessibility.symbols
@@ -0,0 +1,188 @@
+=== tests/cases/conformance/types/thisType/thisTypeAccessibility.ts ===
+class MyClass {
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+
+    private p: number = 123;
+>p : Symbol(MyClass.p, Decl(thisTypeAccessibility.ts, 0, 15))
+
+    protected pp: number = 123;
+>pp : Symbol(MyClass.pp, Decl(thisTypeAccessibility.ts, 1, 28))
+
+    public ppp: number = 123;
+>ppp : Symbol(MyClass.ppp, Decl(thisTypeAccessibility.ts, 2, 31))
+
+    private static sp: number = 123;
+>sp : Symbol(MyClass.sp, Decl(thisTypeAccessibility.ts, 3, 29))
+
+    protected static spp: number = 123;
+>spp : Symbol(MyClass.spp, Decl(thisTypeAccessibility.ts, 4, 36))
+
+    public static sppp: number = 123;
+>sppp : Symbol(MyClass.sppp, Decl(thisTypeAccessibility.ts, 5, 39))
+}
+
+interface MyClass {
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+
+    extension1(p: number): void;
+>extension1 : Symbol(MyClass.extension1, Decl(thisTypeAccessibility.ts, 9, 19))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 10, 15))
+
+    extension2(p: number): void;
+>extension2 : Symbol(MyClass.extension2, Decl(thisTypeAccessibility.ts, 10, 32))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 11, 15))
+
+    extension3(p: number): void;
+>extension3 : Symbol(MyClass.extension3, Decl(thisTypeAccessibility.ts, 11, 32))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 12, 15))
+}
+
+MyClass.prototype.extension1 = function (this: MyClass, p: number) { 
+>MyClass.prototype.extension1 : Symbol(MyClass.extension1, Decl(thisTypeAccessibility.ts, 9, 19))
+>MyClass.prototype : Symbol(MyClass.prototype)
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>prototype : Symbol(MyClass.prototype)
+>extension1 : Symbol(MyClass.extension1, Decl(thisTypeAccessibility.ts, 9, 19))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 15, 41))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 15, 55))
+
+    this.p = p;
+>this.p : Symbol(MyClass.p, Decl(thisTypeAccessibility.ts, 0, 15))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 15, 41))
+>p : Symbol(MyClass.p, Decl(thisTypeAccessibility.ts, 0, 15))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 15, 55))
+
+    this.pp = p;
+>this.pp : Symbol(MyClass.pp, Decl(thisTypeAccessibility.ts, 1, 28))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 15, 41))
+>pp : Symbol(MyClass.pp, Decl(thisTypeAccessibility.ts, 1, 28))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 15, 55))
+
+    this.ppp = p;
+>this.ppp : Symbol(MyClass.ppp, Decl(thisTypeAccessibility.ts, 2, 31))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 15, 41))
+>ppp : Symbol(MyClass.ppp, Decl(thisTypeAccessibility.ts, 2, 31))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 15, 55))
+
+    MyClass.sp = p;
+>MyClass.sp : Symbol(MyClass.sp, Decl(thisTypeAccessibility.ts, 3, 29))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>sp : Symbol(MyClass.sp, Decl(thisTypeAccessibility.ts, 3, 29))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 15, 55))
+
+    MyClass.spp = p;
+>MyClass.spp : Symbol(MyClass.spp, Decl(thisTypeAccessibility.ts, 4, 36))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>spp : Symbol(MyClass.spp, Decl(thisTypeAccessibility.ts, 4, 36))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 15, 55))
+
+    MyClass.sppp = p;
+>MyClass.sppp : Symbol(MyClass.sppp, Decl(thisTypeAccessibility.ts, 5, 39))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>sppp : Symbol(MyClass.sppp, Decl(thisTypeAccessibility.ts, 5, 39))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 15, 55))
+}
+
+MyClass.prototype.extension2 = function<T extends MyClass> (this: T, p: number) { 
+>MyClass.prototype.extension2 : Symbol(MyClass.extension2, Decl(thisTypeAccessibility.ts, 10, 32))
+>MyClass.prototype : Symbol(MyClass.prototype)
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>prototype : Symbol(MyClass.prototype)
+>extension2 : Symbol(MyClass.extension2, Decl(thisTypeAccessibility.ts, 10, 32))
+>T : Symbol(T, Decl(thisTypeAccessibility.ts, 24, 40))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 24, 60))
+>T : Symbol(T, Decl(thisTypeAccessibility.ts, 24, 40))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 24, 68))
+
+    this.p = p;
+>this.p : Symbol(MyClass.p, Decl(thisTypeAccessibility.ts, 0, 15))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 24, 60))
+>p : Symbol(MyClass.p, Decl(thisTypeAccessibility.ts, 0, 15))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 24, 68))
+
+    this.pp = p;
+>this.pp : Symbol(MyClass.pp, Decl(thisTypeAccessibility.ts, 1, 28))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 24, 60))
+>pp : Symbol(MyClass.pp, Decl(thisTypeAccessibility.ts, 1, 28))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 24, 68))
+
+    this.ppp = p;
+>this.ppp : Symbol(MyClass.ppp, Decl(thisTypeAccessibility.ts, 2, 31))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 24, 60))
+>ppp : Symbol(MyClass.ppp, Decl(thisTypeAccessibility.ts, 2, 31))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 24, 68))
+
+    MyClass.sp = p;
+>MyClass.sp : Symbol(MyClass.sp, Decl(thisTypeAccessibility.ts, 3, 29))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>sp : Symbol(MyClass.sp, Decl(thisTypeAccessibility.ts, 3, 29))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 24, 68))
+
+    MyClass.spp = p;
+>MyClass.spp : Symbol(MyClass.spp, Decl(thisTypeAccessibility.ts, 4, 36))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>spp : Symbol(MyClass.spp, Decl(thisTypeAccessibility.ts, 4, 36))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 24, 68))
+
+    MyClass.sppp = p;
+>MyClass.sppp : Symbol(MyClass.sppp, Decl(thisTypeAccessibility.ts, 5, 39))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>sppp : Symbol(MyClass.sppp, Decl(thisTypeAccessibility.ts, 5, 39))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 24, 68))
+}
+
+function extension3<T extends MyClass> (this: T, p: number) { 
+>extension3 : Symbol(extension3, Decl(thisTypeAccessibility.ts, 31, 1))
+>T : Symbol(T, Decl(thisTypeAccessibility.ts, 33, 20))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 33, 40))
+>T : Symbol(T, Decl(thisTypeAccessibility.ts, 33, 20))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 33, 48))
+
+    this.p = p;
+>this.p : Symbol(MyClass.p, Decl(thisTypeAccessibility.ts, 0, 15))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 33, 40))
+>p : Symbol(MyClass.p, Decl(thisTypeAccessibility.ts, 0, 15))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 33, 48))
+
+    this.pp = p;
+>this.pp : Symbol(MyClass.pp, Decl(thisTypeAccessibility.ts, 1, 28))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 33, 40))
+>pp : Symbol(MyClass.pp, Decl(thisTypeAccessibility.ts, 1, 28))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 33, 48))
+
+    this.ppp = p;
+>this.ppp : Symbol(MyClass.ppp, Decl(thisTypeAccessibility.ts, 2, 31))
+>this : Symbol(this, Decl(thisTypeAccessibility.ts, 33, 40))
+>ppp : Symbol(MyClass.ppp, Decl(thisTypeAccessibility.ts, 2, 31))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 33, 48))
+
+    MyClass.sp = p;
+>MyClass.sp : Symbol(MyClass.sp, Decl(thisTypeAccessibility.ts, 3, 29))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>sp : Symbol(MyClass.sp, Decl(thisTypeAccessibility.ts, 3, 29))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 33, 48))
+
+    MyClass.spp = p;
+>MyClass.spp : Symbol(MyClass.spp, Decl(thisTypeAccessibility.ts, 4, 36))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>spp : Symbol(MyClass.spp, Decl(thisTypeAccessibility.ts, 4, 36))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 33, 48))
+
+    MyClass.sppp = p;
+>MyClass.sppp : Symbol(MyClass.sppp, Decl(thisTypeAccessibility.ts, 5, 39))
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>sppp : Symbol(MyClass.sppp, Decl(thisTypeAccessibility.ts, 5, 39))
+>p : Symbol(p, Decl(thisTypeAccessibility.ts, 33, 48))
+}
+
+MyClass.prototype.extension3 = extension3;
+>MyClass.prototype.extension3 : Symbol(MyClass.extension3, Decl(thisTypeAccessibility.ts, 11, 32))
+>MyClass.prototype : Symbol(MyClass.prototype)
+>MyClass : Symbol(MyClass, Decl(thisTypeAccessibility.ts, 0, 0), Decl(thisTypeAccessibility.ts, 7, 1))
+>prototype : Symbol(MyClass.prototype)
+>extension3 : Symbol(MyClass.extension3, Decl(thisTypeAccessibility.ts, 11, 32))
+>extension3 : Symbol(extension3, Decl(thisTypeAccessibility.ts, 31, 1))
+
diff --git a/tests/baselines/reference/thisTypeAccessibility.types b/tests/baselines/reference/thisTypeAccessibility.types
new file mode 100644
index 00000000000..61e9434e4f0
--- /dev/null
+++ b/tests/baselines/reference/thisTypeAccessibility.types
@@ -0,0 +1,217 @@
+=== tests/cases/conformance/types/thisType/thisTypeAccessibility.ts ===
+class MyClass {
+>MyClass : MyClass
+
+    private p: number = 123;
+>p : number
+>123 : 123
+
+    protected pp: number = 123;
+>pp : number
+>123 : 123
+
+    public ppp: number = 123;
+>ppp : number
+>123 : 123
+
+    private static sp: number = 123;
+>sp : number
+>123 : 123
+
+    protected static spp: number = 123;
+>spp : number
+>123 : 123
+
+    public static sppp: number = 123;
+>sppp : number
+>123 : 123
+}
+
+interface MyClass {
+>MyClass : MyClass
+
+    extension1(p: number): void;
+>extension1 : (p: number) => void
+>p : number
+
+    extension2(p: number): void;
+>extension2 : (p: number) => void
+>p : number
+
+    extension3(p: number): void;
+>extension3 : (p: number) => void
+>p : number
+}
+
+MyClass.prototype.extension1 = function (this: MyClass, p: number) { 
+>MyClass.prototype.extension1 = function (this: MyClass, p: number) {     this.p = p;    this.pp = p;    this.ppp = p;    MyClass.sp = p;    MyClass.spp = p;    MyClass.sppp = p;} : (this: MyClass, p: number) => void
+>MyClass.prototype.extension1 : (p: number) => void
+>MyClass.prototype : MyClass
+>MyClass : typeof MyClass
+>prototype : MyClass
+>extension1 : (p: number) => void
+>function (this: MyClass, p: number) {     this.p = p;    this.pp = p;    this.ppp = p;    MyClass.sp = p;    MyClass.spp = p;    MyClass.sppp = p;} : (this: MyClass, p: number) => void
+>this : MyClass
+>MyClass : MyClass
+>p : number
+
+    this.p = p;
+>this.p = p : number
+>this.p : number
+>this : MyClass
+>p : number
+>p : number
+
+    this.pp = p;
+>this.pp = p : number
+>this.pp : number
+>this : MyClass
+>pp : number
+>p : number
+
+    this.ppp = p;
+>this.ppp = p : number
+>this.ppp : number
+>this : MyClass
+>ppp : number
+>p : number
+
+    MyClass.sp = p;
+>MyClass.sp = p : number
+>MyClass.sp : number
+>MyClass : typeof MyClass
+>sp : number
+>p : number
+
+    MyClass.spp = p;
+>MyClass.spp = p : number
+>MyClass.spp : number
+>MyClass : typeof MyClass
+>spp : number
+>p : number
+
+    MyClass.sppp = p;
+>MyClass.sppp = p : number
+>MyClass.sppp : number
+>MyClass : typeof MyClass
+>sppp : number
+>p : number
+}
+
+MyClass.prototype.extension2 = function<T extends MyClass> (this: T, p: number) { 
+>MyClass.prototype.extension2 = function<T extends MyClass> (this: T, p: number) {     this.p = p;    this.pp = p;    this.ppp = p;    MyClass.sp = p;    MyClass.spp = p;    MyClass.sppp = p;} : <T extends MyClass>(this: T, p: number) => void
+>MyClass.prototype.extension2 : (p: number) => void
+>MyClass.prototype : MyClass
+>MyClass : typeof MyClass
+>prototype : MyClass
+>extension2 : (p: number) => void
+>function<T extends MyClass> (this: T, p: number) {     this.p = p;    this.pp = p;    this.ppp = p;    MyClass.sp = p;    MyClass.spp = p;    MyClass.sppp = p;} : <T extends MyClass>(this: T, p: number) => void
+>T : T
+>MyClass : MyClass
+>this : T
+>T : T
+>p : number
+
+    this.p = p;
+>this.p = p : number
+>this.p : number
+>this : T
+>p : number
+>p : number
+
+    this.pp = p;
+>this.pp = p : number
+>this.pp : number
+>this : T
+>pp : number
+>p : number
+
+    this.ppp = p;
+>this.ppp = p : number
+>this.ppp : number
+>this : T
+>ppp : number
+>p : number
+
+    MyClass.sp = p;
+>MyClass.sp = p : number
+>MyClass.sp : number
+>MyClass : typeof MyClass
+>sp : number
+>p : number
+
+    MyClass.spp = p;
+>MyClass.spp = p : number
+>MyClass.spp : number
+>MyClass : typeof MyClass
+>spp : number
+>p : number
+
+    MyClass.sppp = p;
+>MyClass.sppp = p : number
+>MyClass.sppp : number
+>MyClass : typeof MyClass
+>sppp : number
+>p : number
+}
+
+function extension3<T extends MyClass> (this: T, p: number) { 
+>extension3 : <T extends MyClass>(this: T, p: number) => void
+>T : T
+>MyClass : MyClass
+>this : T
+>T : T
+>p : number
+
+    this.p = p;
+>this.p = p : number
+>this.p : number
+>this : T
+>p : number
+>p : number
+
+    this.pp = p;
+>this.pp = p : number
+>this.pp : number
+>this : T
+>pp : number
+>p : number
+
+    this.ppp = p;
+>this.ppp = p : number
+>this.ppp : number
+>this : T
+>ppp : number
+>p : number
+
+    MyClass.sp = p;
+>MyClass.sp = p : number
+>MyClass.sp : number
+>MyClass : typeof MyClass
+>sp : number
+>p : number
+
+    MyClass.spp = p;
+>MyClass.spp = p : number
+>MyClass.spp : number
+>MyClass : typeof MyClass
+>spp : number
+>p : number
+
+    MyClass.sppp = p;
+>MyClass.sppp = p : number
+>MyClass.sppp : number
+>MyClass : typeof MyClass
+>sppp : number
+>p : number
+}
+
+MyClass.prototype.extension3 = extension3;
+>MyClass.prototype.extension3 = extension3 : <T extends MyClass>(this: T, p: number) => void
+>MyClass.prototype.extension3 : (p: number) => void
+>MyClass.prototype : MyClass
+>MyClass : typeof MyClass
+>prototype : MyClass
+>extension3 : (p: number) => void
+>extension3 : <T extends MyClass>(this: T, p: number) => void
+
diff --git a/tests/cases/conformance/types/thisType/thisTypeAccessibility.ts b/tests/cases/conformance/types/thisType/thisTypeAccessibility.ts
new file mode 100644
index 00000000000..6cdc9e71225
--- /dev/null
+++ b/tests/cases/conformance/types/thisType/thisTypeAccessibility.ts
@@ -0,0 +1,43 @@
+class MyClass {
+    private p: number = 123;
+    protected pp: number = 123;
+    public ppp: number = 123;
+    private static sp: number = 123;
+    protected static spp: number = 123;
+    public static sppp: number = 123;
+}
+
+interface MyClass {
+    extension1(p: number): void;
+    extension2(p: number): void;
+    extension3(p: number): void;
+}
+
+MyClass.prototype.extension1 = function (this: MyClass, p: number) { 
+    this.p = p;
+    this.pp = p;
+    this.ppp = p;
+    MyClass.sp = p;
+    MyClass.spp = p;
+    MyClass.sppp = p;
+}
+
+MyClass.prototype.extension2 = function<T extends MyClass> (this: T, p: number) { 
+    this.p = p;
+    this.pp = p;
+    this.ppp = p;
+    MyClass.sp = p;
+    MyClass.spp = p;
+    MyClass.sppp = p;
+}
+
+function extension3<T extends MyClass> (this: T, p: number) { 
+    this.p = p;
+    this.pp = p;
+    this.ppp = p;
+    MyClass.sp = p;
+    MyClass.spp = p;
+    MyClass.sppp = p;
+}
+
+MyClass.prototype.extension3 = extension3;