Expected type did not match the received type. Erroneous code examples: ```compile_fail,E0308 fn plus_one(x: i32) -> i32 { x + 1 } plus_one("Not a number"); // ^^^^^^^^^^^^^^ expected `i32`, found `&str` if "Not a bool" { // ^^^^^^^^^^^^ expected `bool`, found `&str` } let x: f32 = "Not a float"; // --- ^^^^^^^^^^^^^ expected `f32`, found `&str` // | // expected due to this ``` This error occurs when an expression was used in a place where the compiler expected an expression of a different type. It can occur in several cases, the most common being when calling a function and passing an argument which has a different type than the matching type in the function declaration.