tests/cases/compiler/declarationEmitDestructuring2.ts(3,13): error TS2300: Duplicate identifier 'a'. tests/cases/compiler/declarationEmitDestructuring2.ts(3,17): error TS2300: Duplicate identifier 'b'. tests/cases/compiler/declarationEmitDestructuring2.ts(3,23): error TS2300: Duplicate identifier 'c'. tests/cases/compiler/declarationEmitDestructuring2.ts(3,41): error TS2300: Duplicate identifier 'a'. tests/cases/compiler/declarationEmitDestructuring2.ts(3,44): error TS2300: Duplicate identifier 'b'. tests/cases/compiler/declarationEmitDestructuring2.ts(3,47): error TS2300: Duplicate identifier 'c'. ==== tests/cases/compiler/declarationEmitDestructuring2.ts (6 errors) ==== function f({x = 10, y: [a, b, c, d] = [1, 2, 3, 4]} = { x: 10, y: [2, 4, 6, 8] }) { } function g([a, b, c, d] = [1, 2, 3, 4]) { } function h([a, [b], [[c]], {x = 10, y: [a, b, c], z: {a1, b1}}]){ } ~ !!! error TS2300: Duplicate identifier 'a'. ~ !!! error TS2300: Duplicate identifier 'b'. ~ !!! error TS2300: Duplicate identifier 'c'. ~ !!! error TS2300: Duplicate identifier 'a'. ~ !!! error TS2300: Duplicate identifier 'b'. ~ !!! error TS2300: Duplicate identifier 'c'. function h1([a, [b], [[c]], {x = 10, y = [1, 2, 3], z: {a1, b1}}]){ }