report invalid modifiers on class expression properties

Fixes: microsoft#32532

Author: ajafff

src/compiler/checker.ts

@@ -32406,7 +32406,7 @@ namespace ts {
                         else if (flags & ModifierFlags.Async) {
                             return grammarErrorOnNode(modifier, Diagnostics._0_modifier_must_precede_1_modifier, "export", "async");
                         }
-                        else if (node.parent.kind === SyntaxKind.ClassDeclaration) {
+                        else if (isClassLike(node.parent)) {
                             return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_class_element, "export");
                         }
                         else if (node.kind === SyntaxKind.Parameter) {
@@ -32429,7 +32429,7 @@ namespace ts {
                         else if (flags & ModifierFlags.Async) {
                             return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_be_used_in_an_ambient_context, "async");
                         }
-                        else if (node.parent.kind === SyntaxKind.ClassDeclaration) {
+                        else if (isClassLike(node.parent)) {
                             return grammarErrorOnNode(modifier, Diagnostics._0_modifier_cannot_appear_on_a_class_element, "declare");
                         }
                         else if (node.kind === SyntaxKind.Parameter) {

tests/baselines/reference/classExpressionPropertyModifiers.errors.txt

@@ -0,0 +1,14 @@
+tests/cases/compiler/classExpressionPropertyModifiers.ts(2,5): error TS1031: 'declare' modifier cannot appear on a class element.
+tests/cases/compiler/classExpressionPropertyModifiers.ts(3,5): error TS1031: 'export' modifier cannot appear on a class element.
+
+
+==== tests/cases/compiler/classExpressionPropertyModifiers.ts (2 errors) ====
+    const a = class Cat {
+        declare [Symbol.toStringTag] = "uh";
+        ~~~~~~~
+!!! error TS1031: 'declare' modifier cannot appear on a class element.
+        export foo = 1;
+        ~~~~~~
+!!! error TS1031: 'export' modifier cannot appear on a class element.
+    }
+    

tests/cases/compiler/classExpressionPropertyModifiers.ts

@@ -0,0 +1,8 @@
+// @noEmit: true
+// @noTypesAndSymbols: true
+// @lib: es6
+
+const a = class Cat {
+    declare [Symbol.toStringTag] = "uh";
+    export foo = 1;
+}