[ASDAlexander77]

return in a function* was not rewritten by the generator transform:

function* g() { yield "a"; return "end"; }
const r = g().next(); r.value;          // error: Can't resolve property 'value' of type string | {value:string, done:boolean}

function* h(n: number) { yield 1; if (n > 0) return; yield 2; }
for (const v of h(1)) print(v);         // 1, 2, 2, 2, ... forever

The body is pasted into the generated next(), where yield e sets the resume step and returns {value: e, done: false}. A user return stayed a plain return, so it returned the bare value, and it didn't advance the step, so every later next() resumed at the last yield.

Change

• buildGeneratorWrapperDeclaration flags the body's own return statements with InternalFlags::GeneratorReturn (new bit). FilterVisitorSkipFuncsAST leaves the returns of nested functions, arrows and classes alone.
• mlirGen(ReturnStatement) turns a flagged return e into step = -1; return {value: e, done: true}; a bare return gives value: undefined.
• next() starts with if (this.step < 0) return {value: undefined, done: true}, so every call after a return is done. It's a sentinel rather than a final state label because labels are numbered in program order, so a final label's number isn't known yet at an earlier return.

Not changed (exists on main)

The finished value is wrong even without a user return: function* g() { yield "a"; }, and after the last next(), r.value === undefined is false. It reads as the text "undefined" for a string generator and 0 for a number one (warning using casting to undefined value). This is return-type inference dropping undefined from next()'s value type. The new test asserts done and real values only.

Tests

• New 00generator_return.ts (compile + jit): value + done on return, done after it, for...of stopping, an early bare return, a return inside a loop, a nested arrow's return, and a method generator.
• Release suite: 3341/3341 passed.
• DefaultLib (main b67a213) rebuilt release/gc with this compiler: 158/158 compile, 158/158 jit.
• The new test passes under gc, rc and none.
• Not run: Debug, x86, -mm=own.

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