swc/crates/swc_ecma_parser/tests/tsc/constructorParameterShadowsOuterScopes.ts

// Initializer expressions for instance member variables are evaluated in the scope of the class constructor 
// body but are not permitted to reference parameters or local variables of the constructor.
// This effectively means that entities from outer scopes by the same name as a constructor parameter or 
// local variable are inaccessible in initializer expressions for instance member variables

var x = 1;
class C {
    b = x; // error, evaluated in scope of constructor, cannot reference x
    constructor(x: string) {
        x = 2; // error, x is string
    }    
}

var y = 1;
class D {
    b = y; // error, evaluated in scope of constructor, cannot reference y
    constructor(x: string) {
        var y = "";
    }
}