Be strict about trailing characters after braces. Don't give mid-word braces magic meaning.

src/parser2.ts

@@ -71,24 +71,31 @@ class WipScript {
   wipCommand: Word[] = [];
   wipWord: InterpolatedPiece[] = [];
   wordPos: number | undefined = undefined;
-  // TODO: thing to fail {}a & ""a
+  endOfWordError: string | undefined = undefined;
 
   startOfWord(): boolean {
     return this.wipWord.length == 0;
   }
 
   addWordPiece(piece: InterpolatedPiece, pos?: number) {
+    if (this.endOfWordError) {
+      throw new Error(this.endOfWordError);
+    }
     if (this.startOfWord()) {
       this.wordPos = pos;
     }
     this.wipWord.push(piece);
   }
+  freezeWord(error: string) {
+    this.endOfWordError = error;
+  }
   finishWord() {
     if (this.wipWord.length > 0) {
       this.wipCommand.push(SimplifyWord(this.wipWord, this.wordPos));
-      this.wipWord = [];
-      this.wordPos = undefined;
     }
+    this.wipWord = [];
+    this.wordPos = undefined;
+    this.endOfWordError = undefined;
   }
   finishCommand() {
     this.finishWord();
@@ -149,10 +156,15 @@ class Parser {
           break;
 
         case "{": {
-          this.advance();
-          const text = this.parseBrace();
-          wip.addWordPiece({ text }, pos);
-          this.expect("}");
+          if (wip.startOfWord()) {
+            this.advance();
+            const text = this.parseBrace();
+            wip.addWordPiece({ text }, pos);
+            this.expect("}");
+            wip.freezeWord("Extra characters after closing brace");
+          } else {
+            wip.addWordPiece({ bare: chars }, pos);
+          }
           break;
         }