TE001 — `let` type mismatch

Why this fires

The value being assigned to a let does not satisfy the declared type annotation:

let x: int = "hello"
//           ^^^^^^^ error: type mismatch — expected `int`, found `str`

The type checker compares the right-hand side's inferred type against the annotation and surfaces the first incompatibility.

Fix it

1. Convert the value

If you wrote the wrong literal, fix it. If you have a value of a related type, convert it explicitly:

let x: int = tonumber("42") ?? 0     // str → int
let y: float = 3                     // implicit numeric widening
let s: str = tostring(42)            // int → str

2. Change the annotation

Sometimes the right-hand side is correct and the annotation was wrong:

let name: str = "hello"

3. Drop the annotation

If you don't need to pin the type, let inference pick it:

let x = 42       // inferred as `int`
let s = "hello"  // inferred as `str`

In strict mode, annotations are required — see TE201.

Common variants

Tuple shape mismatch: let (a, b): (int, int) = (1, "x") — the second element disagrees.
Optional ↔ non-optional: let x: int = some_optional — wrap with ?? to provide a default.
Mutable / immutable confusion: see TE004.

`let` type mismatch