fix compiler authoring traps and showcase generation order

packages/syntax/src/parser.ts

@@ -439,7 +439,14 @@ export function parse(source: string): PageAst {
           // props { name: Type = <default>; @event name = function }
           lx.next();
           expect("lbrace");
-          while (lx.peek().type !== "rbrace") {
+          while (true) {
+            if (lx.startsWithBlockComment()) {
+              throw new ParseError(
+                "Block comments are not allowed inside props {}; use // line comments instead",
+                "WRN-PROPS-BLOCK-COMMENT",
+              );
+            }
+            if (lx.peek().type === "rbrace") break;
             const t = lx.peek();
             if (t.type === "eof") throw new ParseError("Unexpected end of input inside props");
             if (t.type === "at") {
@@ -829,6 +836,13 @@ export function parse(source: string): PageAst {
 
     const declaredStates = new Set(states.map((state) => state.name));
 
+    if (declaredStates.has("page")) {
+      throw new ParseError(
+        "State name 'page' collides with the WRN 'page' keyword; choose another state name",
+        "WRN-STATE-RESERVED-NAME",
+      );
+    }
+
     for (const watcher of watches) {
       if (!declaredStates.has(watcher.state)) {
         throw new ParseError(`Cannot watch undeclared state '${watcher.state}'`);

packages/syntax/src/tokenizer.ts

@@ -55,6 +55,12 @@ export class Lexer {
     }
   }
 
+  /** True when the next non-trivia characters open a block comment. */
+  startsWithBlockComment(): boolean {
+    this.skipTrivia();
+    return this.src[this.pos] === "/" && this.src[this.pos + 1] === "*";
+  }
+
   /** Read and consume the next structural token. */
   next(): Token {
     this.skipTrivia();