fix: escape single quotes and backslashes in IR string output

Strings containing single quotes or backslashes would break the IR
parser because appendQuotedString emitted them unescaped inside
single-quote delimiters.

- Add escapeIRString() helper that escapes \, ', \n, \r, \t
- Apply it in appendQuotedString() (removes the long-standing TODO)
- Fix the LiteralString IR case to route through appendQuotedString
  instead of its own inline template literal
- Add two regression tests (single-quote and backslash in string literals)

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

Author: AugustHagedal

compiler/companion/src/native/IRtoString.ts

@@ -93,6 +93,15 @@ function variableToString(variable: NativeCompilerBuilderVariableID): string {
   return variable.variable.toString();
 }
 
+function escapeIRString(str: string): string {
+  return str
+    .replace(/\\/g, '\\\\')  // backslash first
+    .replace(/'/g, "\\'")    // single quote
+    .replace(/\n/g, '\\n')   // newline
+    .replace(/\r/g, '\\r')   // carriage return
+    .replace(/\t/g, '\\t');  // tab
+}
+
 class IRStringWriter {
   constructor(readonly writer: OutputWriter) {}
 
@@ -105,8 +114,7 @@ class IRStringWriter {
     if (str === undefined) {
       return this.append(' <null>');
     } else {
-      // TODO(simon): Escape quotes
-      return this.append(` '${str}'`);
+      return this.append(` '${escapeIRString(str)}'`);
     }
   }
 
@@ -355,7 +363,7 @@ function outputIR(ir: NativeCompilerIR.Base, output: IRStringWriter): IRStringWr
 
       // storestring '<string_value>' <output_variable>
 
-      return output.append(`storestring '${typedIR.value}'`).appendVariable(typedIR.variable);
+      return output.append('storestring').appendQuotedString(typedIR.value).appendVariable(typedIR.variable);
     }
     case NativeCompilerIR.Kind.LiteralBool: {
       const typedIR = ir as NativeCompilerIR.LiteralBool;

compiler/companion/src/native/NativeCompiler.spec.ts

@@ -4035,4 +4035,28 @@ function_end @1
       `.trim(),
     );
   });
+
+  it('escapes single quotes in string literals', () => {
+    const result = configuredCompile(
+      `
+      const enum Foo { Value = "it's a test" }
+      const s = Foo.Value;
+      `,
+      { optimizeSlots: false, optimizeVarRefs: true },
+      false, false, false, false, undefined,
+    );
+    expect(result).toContain("storestring 'it\\'s a test'");
+  });
+
+  it('escapes backslashes in string literals', () => {
+    const result = configuredCompile(
+      String.raw`
+      const enum Foo { Value = "C:\\Users\\file" }
+      const s = Foo.Value;
+      `,
+      { optimizeSlots: false, optimizeVarRefs: true },
+      false, false, false, false, undefined,
+    );
+    expect(result).toContain("storestring 'C:\\\\Users\\\\file'");
+  });
 });