Support for auto-accessor fields from the Stage 3 Decorators proposal (#49705)

* Support for auto-accessor fields

* Add tests, ensure accessors are initialized in ctor

* classFields cleanup and PR feedback

Author: rbuckton

scripts/eslint/rules/debug-assert.js

@@ -46,7 +46,7 @@ module.exports = createRule({
                 context.report({ messageId: "secondArgumentDebugAssertError", node: message1Node });
             }
 
-            if (argsLen < 3) {
+            if (argsLen !== 3) {
                 return;
             }
 

src/compiler/binder.ts

@@ -2732,7 +2732,10 @@ namespace ts {
         }
 
         function bindPropertyWorker(node: PropertyDeclaration | PropertySignature) {
-            return bindPropertyOrMethodOrAccessor(node, SymbolFlags.Property | (node.questionToken ? SymbolFlags.Optional : SymbolFlags.None), SymbolFlags.PropertyExcludes);
+            const isAutoAccessor = isAutoAccessorPropertyDeclaration(node);
+            const includes = isAutoAccessor ? SymbolFlags.Accessor : SymbolFlags.Property;
+            const excludes = isAutoAccessor ? SymbolFlags.AccessorExcludes : SymbolFlags.PropertyExcludes;
+            return bindPropertyOrMethodOrAccessor(node, includes | (node.questionToken ? SymbolFlags.Optional : SymbolFlags.None), excludes);
         }
 
         function bindAnonymousTypeWorker(node: TypeLiteralNode | MappedTypeNode | JSDocTypeLiteral) {