Expected type did not match the received type.
Erroneous code example:
let x: i32 = "I am not a number!";
// ~~~ ~~~~~~~~~~~~~~~~~~~~
// | |
// | initializing expression;
// | compiler infers type `&str`
// |
// type `i32` assigned to variable `x`
This error occurs when the compiler was unable to infer the concrete type of a variable. It can occur for several cases, the most common of which is a mismatch in the expected type that the compiler inferred for a variable's initializing expression, and the actual type explicitly assigned to the variable.