Improve error message for accessing instance properties via super

tsc/internal/checker/checker.go

@@ -12002,7 +12002,7 @@ func (c *Checker) checkPropertyAccessibilityAtLocation(location *ast.Node, isSup
 		// This is true for both [[Set]] (old) and [[Define]] (ES spec) semantics.
 		if flags&ast.ModifierFlagsStatic == 0 && core.Some(prop.Declarations, isClassInstanceProperty) {
 			if errorNode != nil {
-				c.error(errorNode, diagnostics.Class_field_0_defined_by_the_parent_class_is_not_accessible_in_the_child_class_via_super, c.symbolToString(prop))
+				c.error(errorNode, diagnostics.Instance_property_0_is_defined_by_the_superclass_and_must_be_accessed_through_this_not_super, c.symbolToString(prop))
 			}
 			return false
 		}

tsc/internal/diagnostics/diagnosticMessages.json

@@ -3930,7 +3930,7 @@
         "category": "Error",
         "code": 2854
     },
-    "Class field '{0}' defined by the parent class is not accessible in the child class via super.": {
+    "Instance property '{0}' is defined by the superclass and must be accessed through 'this', not 'super'.": {
         "category": "Error",
         "code": 2855
     },

tsc/testdata/baselines/reference/compiler/checkSuperCallBeforeThisAccess.errors.txt

@@ -1,19 +1,19 @@
 checkSuperCallBeforeThisAccess.ts(7,18): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(8,18): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(9,18): error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
-checkSuperCallBeforeThisAccess.ts(9,24): error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
-checkSuperCallBeforeThisAccess.ts(12,30): error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
-checkSuperCallBeforeThisAccess.ts(17,28): error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
+checkSuperCallBeforeThisAccess.ts(9,24): error TS2855: Instance property 'x' is defined by the superclass and must be accessed through 'this', not 'super'.
+checkSuperCallBeforeThisAccess.ts(12,30): error TS2855: Instance property 'x' is defined by the superclass and must be accessed through 'this', not 'super'.
+checkSuperCallBeforeThisAccess.ts(17,28): error TS2855: Instance property 'x' is defined by the superclass and must be accessed through 'this', not 'super'.
 checkSuperCallBeforeThisAccess.ts(20,22): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(21,22): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(22,22): error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
-checkSuperCallBeforeThisAccess.ts(22,28): error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
+checkSuperCallBeforeThisAccess.ts(22,28): error TS2855: Instance property 'x' is defined by the superclass and must be accessed through 'this', not 'super'.
 checkSuperCallBeforeThisAccess.ts(30,30): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(39,22): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(43,18): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(44,18): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(45,18): error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
-checkSuperCallBeforeThisAccess.ts(45,24): error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
+checkSuperCallBeforeThisAccess.ts(45,24): error TS2855: Instance property 'x' is defined by the superclass and must be accessed through 'this', not 'super'.
 checkSuperCallBeforeThisAccess.ts(59,27): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 checkSuperCallBeforeThisAccess.ts(75,27): error TS17009: 'super' must be called before accessing 'this' in the constructor of a derived class.
 
@@ -35,19 +35,19 @@ checkSuperCallBeforeThisAccess.ts(75,27): error TS17009: 'super' must be called
                      ~~~~~
 !!! error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
                            ~
-!!! error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'x' is defined by the superclass and must be accessed through 'this', not 'super'.
             let a4 = () => this;
             let a5 = () => this.x;
             let a6 = () => super.x;
                                  ~
-!!! error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'x' is defined by the superclass and must be accessed through 'this', not 'super'.
             if (!!true) {
                 super();
                 let b1 = this;
                 let b2 = this.x;
                 let b3 = super.x;
                                ~
-!!! error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'x' is defined by the superclass and must be accessed through 'this', not 'super'.
             }
             else {
                 let c1 = this;  // Error
@@ -60,7 +60,7 @@ checkSuperCallBeforeThisAccess.ts(75,27): error TS17009: 'super' must be called
                          ~~~~~
 !!! error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
                                ~
-!!! error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'x' is defined by the superclass and must be accessed through 'this', not 'super'.
             }
             if (!!true) {
                 switch (n) {
@@ -95,7 +95,7 @@ checkSuperCallBeforeThisAccess.ts(75,27): error TS17009: 'super' must be called
                      ~~~~~
 !!! error TS17011: 'super' must be called before accessing a property of 'super' in the constructor of a derived class.
                            ~
-!!! error TS2855: Class field 'x' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'x' is defined by the superclass and must be accessed through 'this', not 'super'.
         }
     }
 

tsc/testdata/baselines/reference/compiler/classFieldSuperNotAccessible.errors.txt

@@ -1,4 +1,4 @@
-classFieldSuperNotAccessible.ts(6,15): error TS2855: Class field 'field' defined by the parent class is not accessible in the child class via super.
+classFieldSuperNotAccessible.ts(6,15): error TS2855: Instance property 'field' is defined by the superclass and must be accessed through 'this', not 'super'.
 
 
 ==== classFieldSuperNotAccessible.ts (1 errors) ====
@@ -9,7 +9,7 @@ classFieldSuperNotAccessible.ts(6,15): error TS2855: Class field 'field' defined
         f() {
             super.field() // error
                   ~~~~~
-!!! error TS2855: Class field 'field' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'field' is defined by the superclass and must be accessed through 'this', not 'super'.
         }
     }
 

tsc/testdata/baselines/reference/compiler/classFieldSuperNotAccessibleJs.errors.txt

@@ -1,8 +1,8 @@
 index.js(7,14): error TS2339: Property 'justProp' does not exist on type 'YaddaBase'.
 index.js(9,9): error TS7053: Element implicitly has an 'any' type because expression of type '"literalElementAccess"' can't be used to index type 'YaddaBase'.
   Property 'literalElementAccess' does not exist on type 'YaddaBase'.
-index.js(20,22): error TS2855: Class field 'roots' defined by the parent class is not accessible in the child class via super.
-index.js(23,22): error TS2855: Class field 'foo' defined by the parent class is not accessible in the child class via super.
+index.js(20,22): error TS2855: Instance property 'roots' is defined by the superclass and must be accessed through 'this', not 'super'.
+index.js(23,22): error TS2855: Instance property 'foo' is defined by the superclass and must be accessed through 'this', not 'super'.
 index.js(26,22): error TS2339: Property 'justProp' does not exist on type 'YaddaBase'.
 index.js(29,22): error TS2339: Property 'literalElementAccess' does not exist on type 'YaddaBase'.
 
@@ -34,12 +34,12 @@ index.js(29,22): error TS2339: Property 'literalElementAccess' does not exist on
         get rootTests() {
             return super.roots;
                          ~~~~~
-!!! error TS2855: Class field 'roots' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'roots' is defined by the superclass and must be accessed through 'this', not 'super'.
         }
         get fooTests() {
             return super.foo;
                          ~~~
-!!! error TS2855: Class field 'foo' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'foo' is defined by the superclass and must be accessed through 'this', not 'super'.
         }
         get justPropTests() {
             return super.justProp;

tsc/testdata/baselines/reference/compiler/superAccess(target=es2015).errors.txt

@@ -1,6 +1,6 @@
 superAccess.ts(9,24): error TS2576: Property 'S1' does not exist on type 'MyBase'. Did you mean to access the static member 'MyBase.S1' instead?
-superAccess.ts(10,24): error TS2855: Class field 'S2' defined by the parent class is not accessible in the child class via super.
-superAccess.ts(11,24): error TS2855: Class field 'f' defined by the parent class is not accessible in the child class via super.
+superAccess.ts(10,24): error TS2855: Instance property 'S2' is defined by the superclass and must be accessed through 'this', not 'super'.
+superAccess.ts(11,24): error TS2855: Instance property 'f' is defined by the superclass and must be accessed through 'this', not 'super'.
 
 
 ==== superAccess.ts (3 errors) ====
@@ -17,9 +17,9 @@ superAccess.ts(11,24): error TS2855: Class field 'f' defined by the parent class
 !!! error TS2576: Property 'S1' does not exist on type 'MyBase'. Did you mean to access the static member 'MyBase.S1' instead?
             var l4 = super.S2;    // Expected => Error: Only public instance methods of the base class are accessible via the 'super' keyword
                            ~~
-!!! error TS2855: Class field 'S2' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'S2' is defined by the superclass and must be accessed through 'this', not 'super'.
             var l5 = super.f();   // Expected => Error: Only public instance methods of the base class are accessible via the 'super' keyword
                            ~
-!!! error TS2855: Class field 'f' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'f' is defined by the superclass and must be accessed through 'this', not 'super'.
         }
     }

tsc/testdata/baselines/reference/compiler/superAccessProtectedInstanceProperty.errors.txt

@@ -0,0 +1,18 @@
+superAccessProtectedInstanceProperty.ts(9,22): error TS2855: Instance property 'roots' is defined by the superclass and must be accessed through 'this', not 'super'.
+
+
+==== superAccessProtectedInstanceProperty.ts (1 errors) ====
+    // https://github.com/microsoft/TypeScript/issues/55883
+
+    export abstract class YaddaBase {
+        protected roots = "hi";
+    }
+
+    export class DerivedYadda extends YaddaBase {
+        public get rootTests() {
+            return super.roots;
+                         ~~~~~
+!!! error TS2855: Instance property 'roots' is defined by the superclass and must be accessed through 'this', not 'super'.
+        }
+    }
+

tsc/testdata/baselines/reference/compiler/superAccessProtectedInstanceProperty.js

@@ -0,0 +1,26 @@
+//// [tests/cases/compiler/superAccessProtectedInstanceProperty.ts] ////
+
+//// [superAccessProtectedInstanceProperty.ts]
+// https://github.com/microsoft/TypeScript/issues/55883
+
+export abstract class YaddaBase {
+    protected roots = "hi";
+}
+
+export class DerivedYadda extends YaddaBase {
+    public get rootTests() {
+        return super.roots;
+    }
+}
+
+
+//// [superAccessProtectedInstanceProperty.js]
+// https://github.com/microsoft/TypeScript/issues/55883
+export class YaddaBase {
+    roots = "hi";
+}
+export class DerivedYadda extends YaddaBase {
+    get rootTests() {
+        return super.roots;
+    }
+}

tsc/testdata/baselines/reference/compiler/superAccessProtectedInstanceProperty.symbols

@@ -0,0 +1,26 @@
+//// [tests/cases/compiler/superAccessProtectedInstanceProperty.ts] ////
+
+=== superAccessProtectedInstanceProperty.ts ===
+// https://github.com/microsoft/TypeScript/issues/55883
+
+export abstract class YaddaBase {
+>YaddaBase : Symbol(YaddaBase, Decl(superAccessProtectedInstanceProperty.ts, 0, 0))
+
+    protected roots = "hi";
+>roots : Symbol(YaddaBase.roots, Decl(superAccessProtectedInstanceProperty.ts, 2, 33))
+}
+
+export class DerivedYadda extends YaddaBase {
+>DerivedYadda : Symbol(DerivedYadda, Decl(superAccessProtectedInstanceProperty.ts, 4, 1))
+>YaddaBase : Symbol(YaddaBase, Decl(superAccessProtectedInstanceProperty.ts, 0, 0))
+
+    public get rootTests() {
+>rootTests : Symbol(DerivedYadda.rootTests, Decl(superAccessProtectedInstanceProperty.ts, 6, 45))
+
+        return super.roots;
+>super.roots : Symbol(YaddaBase.roots, Decl(superAccessProtectedInstanceProperty.ts, 2, 33))
+>super : Symbol(YaddaBase, Decl(superAccessProtectedInstanceProperty.ts, 0, 0))
+>roots : Symbol(YaddaBase.roots, Decl(superAccessProtectedInstanceProperty.ts, 2, 33))
+    }
+}
+

tsc/testdata/baselines/reference/compiler/superAccessProtectedInstanceProperty.types

@@ -0,0 +1,27 @@
+//// [tests/cases/compiler/superAccessProtectedInstanceProperty.ts] ////
+
+=== superAccessProtectedInstanceProperty.ts ===
+// https://github.com/microsoft/TypeScript/issues/55883
+
+export abstract class YaddaBase {
+>YaddaBase : YaddaBase
+
+    protected roots = "hi";
+>roots : string
+>"hi" : "hi"
+}
+
+export class DerivedYadda extends YaddaBase {
+>DerivedYadda : DerivedYadda
+>YaddaBase : YaddaBase
+
+    public get rootTests() {
+>rootTests : string
+
+        return super.roots;
+>super.roots : string
+>super : YaddaBase
+>roots : string
+    }
+}
+

tsc/testdata/baselines/reference/compiler/superInLambdas(target=es2015).errors.txt

@@ -1,5 +1,5 @@
-superInLambdas.ts(47,49): error TS2855: Class field 'name' defined by the parent class is not accessible in the child class via super.
-superInLambdas.ts(51,49): error TS2855: Class field 'name' defined by the parent class is not accessible in the child class via super.
+superInLambdas.ts(47,49): error TS2855: Instance property 'name' is defined by the superclass and must be accessed through 'this', not 'super'.
+superInLambdas.ts(51,49): error TS2855: Instance property 'name' is defined by the superclass and must be accessed through 'this', not 'super'.
 superInLambdas.ts(61,34): error TS1034: 'super' must be followed by an argument list or member access.
 superInLambdas.ts(65,34): error TS1034: 'super' must be followed by an argument list or member access.
 
@@ -53,13 +53,13 @@ superInLambdas.ts(65,34): error TS1034: 'super' must be followed by an argument
             // super property in a nested lambda in a constructor 
             var superName = () => () => () => super.name;
                                                     ~~~~
-!!! error TS2855: Class field 'name' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'name' is defined by the superclass and must be accessed through 'this', not 'super'.
         }
         sayHello(): void {
             // super property in a nested lambda in a method
             var superName = () => () => () => super.name;
                                                     ~~~~
-!!! error TS2855: Class field 'name' defined by the parent class is not accessible in the child class via super.
+!!! error TS2855: Instance property 'name' is defined by the superclass and must be accessed through 'this', not 'super'.
         }
     }