Add a more helpful error message when you haven't defined an allocator (#108)

Also adds a system for writing tests that assert that certain error codes are triggered so that I could test this.

src/builtins.ts

@@ -2721,6 +2721,10 @@ export function compileAllocate(
       DiagnosticCode.Cannot_find_name_0,
       reportNode.range, allocateInternalName
     );
+    program.info(
+      DiagnosticCode.An_allocator_must_be_declared_to_allocate_memory_Try_importing_allocator_arena_or_allocator_tlsf,
+      reportNode.range
+    );
     return module.createUnreachable();
   }
   if (allocatePrototype.kind != ElementKind.FUNCTION_PROTOTYPE) {

src/diagnosticMessages.generated.ts

@@ -23,6 +23,7 @@ export enum DiagnosticCode {
   Class_0_is_sealed_and_cannot_be_extended = 211,
   Decorator_0_is_not_valid_here = 212,
   Duplicate_decorator = 213,
+  An_allocator_must_be_declared_to_allocate_memory_Try_importing_allocator_arena_or_allocator_tlsf = 214,
   Unterminated_string_literal = 1002,
   Identifier_expected = 1003,
   _0_expected = 1005,
@@ -131,6 +132,7 @@ export function diagnosticCodeToString(code: DiagnosticCode): string {
     case 211: return "Class '{0}' is sealed and cannot be extended.";
     case 212: return "Decorator '{0}' is not valid here.";
     case 213: return "Duplicate decorator.";
+    case 214: return "An allocator must be declared to allocate memory. Try importing allocator/arena or allocator/tlsf.";
     case 1002: return "Unterminated string literal.";
     case 1003: return "Identifier expected.";
     case 1005: return "'{0}' expected.";

src/diagnosticMessages.json

@@ -15,6 +15,7 @@
   "Class '{0}' is sealed and cannot be extended.": 211,
   "Decorator '{0}' is not valid here.": 212,
   "Duplicate decorator.": 213,
+  "An allocator must be declared to allocate memory. Try importing allocator/arena or allocator/tlsf.": 214,
 
   "Unterminated string literal.": 1002,
   "Identifier expected.": 1003,

tests/compiler.js

@@ -40,10 +40,23 @@ if (args._.length) {
   }
 }
 
+const EXPECT_ERROR_PREFIX = '// Expect error:';
+
+// Returns an array of error strings to expect, or null if compilation should succeed.
+function getExpectedErrors(filePath) {
+  const lines = fs.readFileSync(filePath).toString().split('\n');
+  const expectErrorLines = lines.filter(line => line.startsWith(EXPECT_ERROR_PREFIX));
+  if (expectErrorLines.length === 0) {
+    return null;
+  }
+  return expectErrorLines.map(line => line.slice(EXPECT_ERROR_PREFIX.length).trim());
+}
+
 // TODO: asc's callback is synchronous here. This might change.
 tests.forEach(filename => {
   console.log(chalk.whiteBright("Testing compiler/" + filename) + "\n");
 
+  const expectedErrors = getExpectedErrors(path.join(basedir, filename));
   const basename = filename.replace(/\.ts$/, "");
 
   const stdout = asc.createMemoryStream();
@@ -66,6 +79,24 @@ tests.forEach(filename => {
     stderr: stderr
   }, err => {
     console.log();
+
+    if (expectedErrors) {
+      const stderrString = stderr.toString();
+      for (const expectedError of expectedErrors) {
+        if (!stderrString.includes(expectedError)) {
+          console.log(`Expected error "${expectedError}" was not in the error output.`);
+          console.log("- " + chalk.red("error check ERROR"));
+          failedTests.push(basename);
+          console.log();
+          return;
+        }
+      }
+      console.log("- " + chalk.green("error check OK"));
+      ++successes;
+      console.log();
+      return;
+    }
+
     if (err)
       stderr.write(err + os.EOL);
     var actual = stdout.toString().replace(/\r\n/g, "\n");

tests/compiler/new-without-allocator.ts

@@ -0,0 +1,8 @@
+// Expect error: TS2304: Cannot find name 'allocate_memory'.
+// Expect error: AS214: An allocator must be declared to allocate memory. Try importing allocator/arena or allocator/tlsf.
+class A {}
+
+export function test(): i32 {
+  var a = new A();
+  return 3;
+}