Updated error message for TS2539

src/compiler/checker.ts

@@ -23691,7 +23691,14 @@ namespace ts {
             if (assignmentKind) {
                 if (!(localOrExportSymbol.flags & SymbolFlags.Variable) &&
                     !(isInJSFile(node) && localOrExportSymbol.flags & SymbolFlags.ValueModule)) {
-                    error(node, Diagnostics.Cannot_assign_to_0_because_it_is_not_a_variable, symbolToString(symbol));
+                    const assignmentError = localOrExportSymbol.flags & SymbolFlags.Enum ? Diagnostics.Cannot_assign_to_0_because_it_is_an_enum
+                        : localOrExportSymbol.flags & SymbolFlags.Class ? Diagnostics.Cannot_assign_to_0_because_it_is_a_class
+                        : localOrExportSymbol.flags & SymbolFlags.Module ? Diagnostics.Cannot_assign_to_0_because_it_is_a_namespace
+                        : localOrExportSymbol.flags & SymbolFlags.Function ? Diagnostics.Cannot_assign_to_0_because_it_is_a_function
+                        : localOrExportSymbol.flags & SymbolFlags.Alias ? Diagnostics.Cannot_assign_to_0_because_it_is_an_import
+                        : Diagnostics.Cannot_assign_to_0_because_it_is_not_a_variable;
+
+                    error(node, assignmentError, symbolToString(symbol));
                     return errorType;
                 }
                 if (isReadonlySymbol(localOrExportSymbol)) {

src/compiler/diagnosticMessages.json

@@ -2654,6 +2654,26 @@
         "category": "Error",
         "code": 2627
     },
+    "Cannot assign to '{0}' because it is an enum.": {
+        "category": "Error",
+        "code": 2628
+    },
+    "Cannot assign to '{0}' because it is a class.": {
+        "category": "Error",
+        "code": 2629
+    },
+    "Cannot assign to '{0}' because it is a function.": {
+        "category": "Error",
+        "code": 2630
+    },
+    "Cannot assign to '{0}' because it is a namespace.": {
+        "category": "Error",
+        "code": 2631
+    },
+    "Cannot assign to '{0}' because it is an import.": {
+        "category": "Error",
+        "code": 2632
+    },
 
     "Cannot augment module '{0}' with value exports because it resolves to a non-module entity.": {
         "category": "Error",

tests/baselines/reference/arithAssignTyping.errors.txt

@@ -1,53 +1,53 @@
-tests/cases/compiler/arithAssignTyping.ts(3,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(4,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(5,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(6,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(7,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(8,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(9,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(10,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(11,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(12,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(13,1): error TS2539: Cannot assign to 'f' because it is not a variable.
-tests/cases/compiler/arithAssignTyping.ts(14,1): error TS2539: Cannot assign to 'f' because it is not a variable.
+tests/cases/compiler/arithAssignTyping.ts(3,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(4,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(5,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(6,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(7,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(8,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(9,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(10,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(11,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(12,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(13,1): error TS2629: Cannot assign to 'f' because it is a class.
+tests/cases/compiler/arithAssignTyping.ts(14,1): error TS2629: Cannot assign to 'f' because it is a class.
 
 
 ==== tests/cases/compiler/arithAssignTyping.ts (12 errors) ====
     class f { }
 
     f += ''; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f += 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f -= 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f *= 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f /= 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f %= 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f &= 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f |= 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f <<= 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f >>= 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f >>>= 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.
     f ^= 1; // error
     ~
-!!! error TS2539: Cannot assign to 'f' because it is not a variable.
+!!! error TS2629: Cannot assign to 'f' because it is a class.

tests/baselines/reference/assignAnyToEveryType.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/conformance/types/any/assignAnyToEveryType.ts(41,1): error TS2539: Cannot assign to 'M' because it is not a variable.
+tests/cases/conformance/types/any/assignAnyToEveryType.ts(41,1): error TS2631: Cannot assign to 'M' because it is a namespace.
 
 
 ==== tests/cases/conformance/types/any/assignAnyToEveryType.ts (1 errors) ====
@@ -44,7 +44,7 @@ tests/cases/conformance/types/any/assignAnyToEveryType.ts(41,1): error TS2539: C
 
     M = x;
     ~
-!!! error TS2539: Cannot assign to 'M' because it is not a variable.
+!!! error TS2631: Cannot assign to 'M' because it is a namespace.
 
     function k<T>(a: T) {
         a = x;

tests/baselines/reference/assignToEnum.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/compiler/assignToEnum.ts(2,1): error TS2539: Cannot assign to 'A' because it is not a variable.
-tests/cases/compiler/assignToEnum.ts(3,1): error TS2539: Cannot assign to 'A' because it is not a variable.
+tests/cases/compiler/assignToEnum.ts(2,1): error TS2628: Cannot assign to 'A' because it is an enum.
+tests/cases/compiler/assignToEnum.ts(3,1): error TS2628: Cannot assign to 'A' because it is an enum.
 tests/cases/compiler/assignToEnum.ts(4,3): error TS2540: Cannot assign to 'foo' because it is a read-only property.
 tests/cases/compiler/assignToEnum.ts(5,3): error TS2540: Cannot assign to 'foo' because it is a read-only property.
 
@@ -8,10 +8,10 @@ tests/cases/compiler/assignToEnum.ts(5,3): error TS2540: Cannot assign to 'foo'
     enum A { foo, bar }
     A = undefined;  // invalid LHS
     ~
-!!! error TS2539: Cannot assign to 'A' because it is not a variable.
+!!! error TS2628: Cannot assign to 'A' because it is an enum.
     A = A.bar;      // invalid LHS
     ~
-!!! error TS2539: Cannot assign to 'A' because it is not a variable.
+!!! error TS2628: Cannot assign to 'A' because it is an enum.
     A.foo = 1;      // invalid LHS
       ~~~
 !!! error TS2540: Cannot assign to 'foo' because it is a read-only property.

tests/baselines/reference/assignToExistingClass.errors.txt

@@ -1,4 +1,4 @@
-tests/cases/compiler/assignToExistingClass.ts(8,13): error TS2539: Cannot assign to 'Mocked' because it is not a variable.
+tests/cases/compiler/assignToExistingClass.ts(8,13): error TS2629: Cannot assign to 'Mocked' because it is a class.
 
 
 ==== tests/cases/compiler/assignToExistingClass.ts (1 errors) ====
@@ -11,7 +11,7 @@ tests/cases/compiler/assignToExistingClass.ts(8,13): error TS2539: Cannot assign
             willThrowError() {
                 Mocked = Mocked || function () { // => Error: Invalid left-hand side of assignment expression.
                 ~~~~~~
-!!! error TS2539: Cannot assign to 'Mocked' because it is not a variable.
+!!! error TS2629: Cannot assign to 'Mocked' because it is a class.
                     return { myProp: "test" };
                 };
             }

tests/baselines/reference/assignmentLHSIsValue.errors.txt

@@ -3,10 +3,10 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(8,21): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(11,18): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(13,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(17,1): error TS2539: Cannot assign to 'M' because it is not a variable.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(19,1): error TS2539: Cannot assign to 'C' because it is not a variable.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(22,1): error TS2539: Cannot assign to 'E' because it is not a variable.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(24,1): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(17,1): error TS2631: Cannot assign to 'M' because it is a namespace.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(19,1): error TS2629: Cannot assign to 'C' because it is a class.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(22,1): error TS2628: Cannot assign to 'E' because it is an enum.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(24,1): error TS2630: Cannot assign to 'foo' because it is a function.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(27,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(28,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(29,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
@@ -23,10 +23,10 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(5
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(51,11): error TS1005: ';' expected.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(54,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(57,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(58,2): error TS2539: Cannot assign to 'M' because it is not a variable.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(59,2): error TS2539: Cannot assign to 'C' because it is not a variable.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(60,2): error TS2539: Cannot assign to 'E' because it is not a variable.
-tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(61,2): error TS2539: Cannot assign to 'foo' because it is not a variable.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(58,2): error TS2631: Cannot assign to 'M' because it is a namespace.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(59,2): error TS2629: Cannot assign to 'C' because it is a class.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(60,2): error TS2628: Cannot assign to 'E' because it is an enum.
+tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(61,2): error TS2630: Cannot assign to 'foo' because it is a function.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(62,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(63,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(64,1): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
@@ -67,20 +67,20 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
     module M { export var a; }
     M = value;
     ~
-!!! error TS2539: Cannot assign to 'M' because it is not a variable.
+!!! error TS2631: Cannot assign to 'M' because it is a namespace.
 
     C = value;
     ~
-!!! error TS2539: Cannot assign to 'C' because it is not a variable.
+!!! error TS2629: Cannot assign to 'C' because it is a class.
 
     enum E { }
     E = value;
     ~
-!!! error TS2539: Cannot assign to 'E' because it is not a variable.
+!!! error TS2628: Cannot assign to 'E' because it is an enum.
 
     foo = value;
     ~~~
-!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
+!!! error TS2630: Cannot assign to 'foo' because it is a function.
 
     // literals
     null = value;
@@ -148,16 +148,16 @@ tests/cases/conformance/expressions/assignmentOperator/assignmentLHSIsValue.ts(7
 !!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     (M) = value;
      ~
-!!! error TS2539: Cannot assign to 'M' because it is not a variable.
+!!! error TS2631: Cannot assign to 'M' because it is a namespace.
     (C) = value;
      ~
-!!! error TS2539: Cannot assign to 'C' because it is not a variable.
+!!! error TS2629: Cannot assign to 'C' because it is a class.
     (E) = value;
      ~
-!!! error TS2539: Cannot assign to 'E' because it is not a variable.
+!!! error TS2628: Cannot assign to 'E' because it is an enum.
     (foo) = value;
      ~~~
-!!! error TS2539: Cannot assign to 'foo' because it is not a variable.
+!!! error TS2630: Cannot assign to 'foo' because it is a function.
     (null) = value;
     ~~~~~~
 !!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.

tests/baselines/reference/assignmentToFunction.errors.txt

@@ -1,19 +1,19 @@
-tests/cases/compiler/assignmentToFunction.ts(2,1): error TS2539: Cannot assign to 'fn' because it is not a variable.
-tests/cases/compiler/assignmentToFunction.ts(8,9): error TS2539: Cannot assign to 'bar' because it is not a variable.
+tests/cases/compiler/assignmentToFunction.ts(2,1): error TS2630: Cannot assign to 'fn' because it is a function.
+tests/cases/compiler/assignmentToFunction.ts(8,9): error TS2630: Cannot assign to 'bar' because it is a function.
 
 
 ==== tests/cases/compiler/assignmentToFunction.ts (2 errors) ====
     function fn() { }
     fn = () => 3;
     ~~
-!!! error TS2539: Cannot assign to 'fn' because it is not a variable.
+!!! error TS2630: Cannot assign to 'fn' because it is a function.
 
     module foo {
         function xyz() {
             function bar() {
             }
             bar = null;
             ~~~
-!!! error TS2539: Cannot assign to 'bar' because it is not a variable.
+!!! error TS2630: Cannot assign to 'bar' because it is a function.
         }
     }