E040: I can't find anything with that name

Turf looked everywhere it knows to look – the current block, any block around it, the whole file – and couldn’t find anything called by that name. No variable, no struct, no enum, nothing. This is the most common error you’ll hit while learning, and it’s almost always one of two very fixable things.

The first is a plain typo:

mut count: int = 0;count = coutn + 1;   // typo! should be "count"

If there’s something similar already declared nearby, Turf will usually notice and suggest it for you right in the error message, so you can just apply the fix it’s pointing at.

The second is forgetting to declare the variable at all before using it:

mut n: int = undeclared_variable;   // this was never created anywhere

In Turf, you always create a variable with mut or immut before you can use it – there’s no way to just start using a name and have it exist automatically:

mut undeclared_variable: int = 5;mut n: int = undeclared_variable;   // now this works

There is a third case, and the error’s hint says so when it applies: the name IS declared, but as a type. A struct, enum or error type is not a value, so it can’t stand alone in an expression:

struct Node { v: int }mut a: int = Node;        // 'Node' is a struct, not a value

To get a value of a struct type, build one with Node::default() (or Node::new(...) if the struct declares a .new method); for an enum, name one of its variants, Color::Red.

If none of those is it, one more thing worth checking: is the name something from a module you haven’t imported yet? A function or type that lives in another module needs import (or the right :: qualifier) before Turf can see it. Once the name resolves to something real, this error clears right up.

Run turf --explain E040 in a terminal to read this again.