Invalid templates produce no diagnostic (parse errors swallowed)

[brandonroberts]

Malformed templates are silently accepted — result.errors is empty. (Also covers ambiguous DI unions A | B, which should emit a "not supported as injection token" diagnostic rather than a silent invalid factory.)

Repro

import { Component } from '@angular/core';
@Component({ selector: 'app-bad', template: '<div><span></div>' })
export class BadComponent {}

Actual

Compiles without populating result.errors; the parse error is swallowed.

Expected

Unclosed/malformed tags surface a template parse diagnostic in result.errors.

Impact

Silently-wrong output with no compile-time signal — a debugging trap.

---

Researched and drafted with Claude Code.