Record todo bailouts in CodegenReactiveFunction

Went over this pass and converted any todos to bailouts, otherwise we continue 
to throw an invariant if there's an internal error

compiler/forget/src/CompilerError.ts

@@ -13,7 +13,7 @@ export enum ErrorSeverity {
 export type CompilerErrorOptions = {
   reason: string;
   severity: ErrorSeverity;
-  nodePath: AnyNodePath;
+  nodePath: AnyNodePath | null;
 };
 type AnyNodePath = NodePath<Node | null | undefined>;
 type CompilerErrorKind = typeof InvalidInputError | typeof TodoError;

compiler/forget/src/CompilerPipeline.ts

@@ -46,11 +46,7 @@ export type CompilerPipelineValue =
 export function* run(
   func: NodePath<t.FunctionDeclaration>
 ): Generator<CompilerPipelineValue, t.Function> {
-  const lowering = lower(func).orElse((error) => {
-    throw error;
-  });
-
-  const hir = lowering.unwrap();
+  const hir = lower(func).unwrap();
   yield log({ kind: "hir", name: "HIR", value: hir });
 
   mergeConsecutiveBlocks(hir);
@@ -153,7 +149,7 @@ export function* run(
     value: reactiveFunction,
   });
 
-  const ast = codegenReactiveFunction(reactiveFunction);
+  const ast = codegenReactiveFunction(reactiveFunction).unwrap();
   yield log({ kind: "ast", name: "Codegen", value: ast });
 
   return ast;

compiler/forget/src/ReactiveScopes/CodegenReactiveFunction.ts

@@ -7,6 +7,7 @@
 
 import * as t from "@babel/types";
 import invariant from "invariant";
+import { CompilerError, ErrorSeverity } from "../CompilerError";
 import {
   BlockId,
   GeneratedSource,
@@ -24,12 +25,12 @@ import {
   ReactiveValue,
   SourceLocation,
 } from "../HIR/HIR";
-import { todoInvariant } from "../Utils/todo";
+import { Err, Ok, Result } from "../Utils/Result";
 import { assertExhaustive } from "../Utils/utils";
 
 export function codegenReactiveFunction(
   fn: ReactiveFunction
-): t.FunctionDeclaration {
+): Result<t.FunctionDeclaration, CompilerError> {
   const cx = new Context();
   const params = fn.params.map((param) => convertIdentifier(param.identifier));
   const body = codegenBlock(cx, fn.body);
@@ -56,13 +57,20 @@ export function codegenReactiveFunction(
       ])
     );
   }
-  return createFunctionDeclaration(
-    fn.loc,
-    fn.id !== null ? convertIdentifier(fn.id) : null,
-    params,
-    body,
-    fn.generator,
-    fn.async
+
+  if (cx.errors.hasErrors()) {
+    return Err(cx.errors);
+  }
+
+  return Ok(
+    createFunctionDeclaration(
+      fn.loc,
+      fn.id !== null ? convertIdentifier(fn.id) : null,
+      params,
+      body,
+      fn.generator,
+      fn.async
+    )
   );
 }
 
@@ -70,6 +78,7 @@ class Context {
   #nextCacheIndex: number = 0;
   #identifiers: Set<Identifier> = new Set();
   temp: Temporaries = new Map();
+  errors: CompilerError = new CompilerError();
 
   get nextCacheIndex(): number {
     return this.#nextCacheIndex++;
@@ -711,17 +720,22 @@ function codegenInstructionValue(
         } else {
           if (t.isVariableDeclaration(stmt)) {
             const declarator = stmt.declarations[0];
-            todoInvariant(
-              false,
-              `Cannot declare variables in a value block, tried to declare '${
+            cx.errors.push({
+              reason: `(CodegenReactiveFunction::codegenInstructionValue) Cannot declare variables in a value block, tried to declare '${
                 (declarator.id as t.Identifier).name
-              }'`
-            );
+              }'`,
+              severity: ErrorSeverity.Todo,
+              nodePath: null,
+            });
+            return t.stringLiteral(`TODO handle ${declarator.id}`);
+          } else {
+            cx.errors.push({
+              reason: `(CodegenReactiveFunction::codegenInstructionValue) Handle conversion of ${stmt.type} to expression`,
+              severity: ErrorSeverity.Todo,
+              nodePath: null,
+            });
+            return t.stringLiteral(`TODO handle ${stmt.type}`);
           }
-          todoInvariant(
-            false,
-            `Handle conversion of ${stmt.type} to expression`
-          );
         }
       });
       if (expressions.length === 0) {
@@ -788,7 +802,6 @@ function codegenValue(
 }
 
 function codegenPlace(cx: Context, place: Place): t.Expression {
-  todoInvariant(place.kind === "Identifier", "support scope values");
   let tmp = cx.temp.get(place.identifier.id);
   if (tmp != null) {
     return tmp;

compiler/forget/src/Utils/Result.ts

@@ -167,6 +167,9 @@ class OkImpl<T> implements Result<T, never> {
   }
 
   unwrapErr(): never {
+    if (this.val instanceof Error) {
+      throw this.val;
+    }
     throw new Error(`Can't unwrap \`Ok\` to \`Err\`: ${this.val}`);
   }
 }
@@ -227,6 +230,9 @@ class ErrImpl<E> implements Result<never, E> {
   }
 
   unwrap(): never {
+    if (this.val instanceof Error) {
+      throw this.val;
+    }
     throw new Error(`Can't unwrap \`Err\` to \`Ok\`: ${this.val}`);
   }
 

compiler/forget/src/__tests__/Result-test.ts

@@ -1,3 +1,4 @@
+import { CompilerError } from "../CompilerError";
 import { Err, Ok, Result } from "../Utils/Result";
 
 function addMax10(a: number, b: number): Result<number, string> {
@@ -9,6 +10,8 @@ function onlyFoo(foo: string): Result<string, string> {
   return foo === "foo" ? Ok(foo) : Err(foo);
 }
 
+class CustomDummyError extends Error {}
+
 describe("Result", () => {
   test(".map", () => {
     expect(addMax10(1, 1).map((n) => n * 2)).toEqual(Ok(4));
@@ -107,6 +110,9 @@ describe("Result", () => {
     }).toThrowErrorMatchingInlineSnapshot(
       `"Can't unwrap \`Err\` to \`Ok\`: 20 is too high"`
     );
+    expect(() => {
+      Err(new CustomDummyError("oops")).unwrap();
+    }).toThrowErrorMatchingInlineSnapshot(`"oops"`);
   });
 
   test(".unwrapOr", () => {
@@ -126,5 +132,8 @@ describe("Result", () => {
       `"Can't unwrap \`Ok\` to \`Err\`: 2"`
     );
     expect(addMax10(10, 10).unwrapErr()).toEqual("20 is too high");
+    expect(() => {
+      Ok(new CustomDummyError("oops")).unwrapErr();
+    }).toThrowErrorMatchingInlineSnapshot(`"oops"`);
   });
 });

compiler/forget/src/__tests__/fixtures/hir/error.while-with-assignment-in-test.expect.md

@@ -19,7 +19,7 @@ function f(reader) {
 ## Error
 
 ```
-TODO: Cannot declare variables in a value block, tried to declare 'value$0'
+[ReactForget] Todo: (CodegenReactiveFunction::codegenInstructionValue) Cannot declare variables in a value block, tried to declare 'value$0'
 ```