add more test case

src/compiler/binder.ts

@@ -1366,6 +1366,7 @@ namespace ts {
             }
         }
 
+        // TODO(rbuckton): Determine how to hook ?? into flow typing
         function bindBinaryExpressionFlow(node: BinaryExpression) {
             const operator = node.operatorToken.kind;
             if (operator === SyntaxKind.AmpersandAmpersandToken || operator === SyntaxKind.BarBarToken || operator === SyntaxKind.QuestionQuestionToken) {

tests/baselines/reference/nullishCoalescingOperator3.js

@@ -0,0 +1,15 @@
+//// [nullishCoalescingOperator3.ts]
+declare const a1: 'literal' | undefined | null
+declare const a2: '' | undefined | null
+declare const a3: 1 | undefined | null
+declare const a4: 0 | undefined | null
+declare const a5: true | undefined | null
+declare const a6: false | undefined | null
+
+
+const aa1 = a1 ?? a2 ?? a3 ?? a4 ?? a5 ?? a6 ?? 'whatever'
+
+
+//// [nullishCoalescingOperator3.js]
+"use strict";
+var aa1 = (_a = (_b = (_c = (_d = (_e = typeof a1 !== "undefined" && a1 !== null ? a1 : a2, _e !== void 0 && _e !== null ? _e : a3), _d !== void 0 && _d !== null ? _d : a4), _c !== void 0 && _c !== null ? _c : a5), _b !== void 0 && _b !== null ? _b : a6), _a !== void 0 && _a !== null ? _a : 'whatever');

tests/baselines/reference/nullishCoalescingOperator3.symbols

@@ -0,0 +1,29 @@
+=== tests/cases/conformance/expressions/nullishCoalescingOperator/nullishCoalescingOperator3.ts ===
+declare const a1: 'literal' | undefined | null
+>a1 : Symbol(a1, Decl(nullishCoalescingOperator3.ts, 0, 13))
+
+declare const a2: '' | undefined | null
+>a2 : Symbol(a2, Decl(nullishCoalescingOperator3.ts, 1, 13))
+
+declare const a3: 1 | undefined | null
+>a3 : Symbol(a3, Decl(nullishCoalescingOperator3.ts, 2, 13))
+
+declare const a4: 0 | undefined | null
+>a4 : Symbol(a4, Decl(nullishCoalescingOperator3.ts, 3, 13))
+
+declare const a5: true | undefined | null
+>a5 : Symbol(a5, Decl(nullishCoalescingOperator3.ts, 4, 13))
+
+declare const a6: false | undefined | null
+>a6 : Symbol(a6, Decl(nullishCoalescingOperator3.ts, 5, 13))
+
+
+const aa1 = a1 ?? a2 ?? a3 ?? a4 ?? a5 ?? a6 ?? 'whatever'
+>aa1 : Symbol(aa1, Decl(nullishCoalescingOperator3.ts, 8, 5))
+>a1 : Symbol(a1, Decl(nullishCoalescingOperator3.ts, 0, 13))
+>a2 : Symbol(a2, Decl(nullishCoalescingOperator3.ts, 1, 13))
+>a3 : Symbol(a3, Decl(nullishCoalescingOperator3.ts, 2, 13))
+>a4 : Symbol(a4, Decl(nullishCoalescingOperator3.ts, 3, 13))
+>a5 : Symbol(a5, Decl(nullishCoalescingOperator3.ts, 4, 13))
+>a6 : Symbol(a6, Decl(nullishCoalescingOperator3.ts, 5, 13))
+

tests/baselines/reference/nullishCoalescingOperator3.types

@@ -0,0 +1,44 @@
+=== tests/cases/conformance/expressions/nullishCoalescingOperator/nullishCoalescingOperator3.ts ===
+declare const a1: 'literal' | undefined | null
+>a1 : "literal" | null | undefined
+>null : null
+
+declare const a2: '' | undefined | null
+>a2 : "" | null | undefined
+>null : null
+
+declare const a3: 1 | undefined | null
+>a3 : 1 | null | undefined
+>null : null
+
+declare const a4: 0 | undefined | null
+>a4 : 0 | null | undefined
+>null : null
+
+declare const a5: true | undefined | null
+>a5 : true | null | undefined
+>true : true
+>null : null
+
+declare const a6: false | undefined | null
+>a6 : false | null | undefined
+>false : false
+>null : null
+
+
+const aa1 = a1 ?? a2 ?? a3 ?? a4 ?? a5 ?? a6 ?? 'whatever'
+>aa1 : boolean | "" | 0 | "literal" | 1 | "whatever"
+>a1 ?? a2 ?? a3 ?? a4 ?? a5 ?? a6 ?? 'whatever' : boolean | "" | 0 | "literal" | 1 | "whatever"
+>a1 ?? a2 ?? a3 ?? a4 ?? a5 ?? a6 : boolean | "" | 0 | "literal" | 1 | null | undefined
+>a1 ?? a2 ?? a3 ?? a4 ?? a5 : true | "" | 0 | "literal" | 1 | null | undefined
+>a1 ?? a2 ?? a3 ?? a4 : "" | 0 | "literal" | 1 | null | undefined
+>a1 ?? a2 ?? a3 : "" | "literal" | 1 | null | undefined
+>a1 ?? a2 : "" | "literal" | null | undefined
+>a1 : "literal" | null | undefined
+>a2 : "" | null | undefined
+>a3 : 1 | null | undefined
+>a4 : 0 | null | undefined
+>a5 : true | null | undefined
+>a6 : false | null | undefined
+>'whatever' : "whatever"
+

tests/baselines/reference/nullishCoalescingOperator_esnext.js

@@ -0,0 +1,36 @@
+//// [nullishCoalescingOperator_esnext.ts]
+// target: esnext
+
+declare const a1: 'literal' | undefined | null
+declare const a2: '' | undefined | null
+declare const a3: 1 | undefined | null
+declare const a4: 0 | undefined | null
+declare const a5: true | undefined | null
+declare const a6: false | undefined | null
+declare const a7: unknown | null
+declare const a8: never | null
+declare const a9: any | null
+
+
+const aa1 = a1 ?? 'whatever'
+const aa2 = a2 ?? 'whatever'
+const aa3 = a3 ?? 'whatever'
+const aa4 = a4 ?? 'whatever'
+const aa5 = a5 ?? 'whatever'
+const aa6 = a6 ?? 'whatever'
+const aa7 = a7 ?? 'whatever'
+const aa8 = a8 ?? 'whatever'
+const aa9 = a9 ?? 'whatever'
+
+//// [nullishCoalescingOperator_esnext.js]
+"use strict";
+// target: esnext
+var aa1 = typeof a1 !== "undefined" && a1 !== null ? a1 : 'whatever';
+var aa2 = typeof a2 !== "undefined" && a2 !== null ? a2 : 'whatever';
+var aa3 = typeof a3 !== "undefined" && a3 !== null ? a3 : 'whatever';
+var aa4 = typeof a4 !== "undefined" && a4 !== null ? a4 : 'whatever';
+var aa5 = typeof a5 !== "undefined" && a5 !== null ? a5 : 'whatever';
+var aa6 = typeof a6 !== "undefined" && a6 !== null ? a6 : 'whatever';
+var aa7 = typeof a7 !== "undefined" && a7 !== null ? a7 : 'whatever';
+var aa8 = typeof a8 !== "undefined" && a8 !== null ? a8 : 'whatever';
+var aa9 = typeof a9 !== "undefined" && a9 !== null ? a9 : 'whatever';

tests/baselines/reference/nullishCoalescingOperator_esnext.symbols

@@ -0,0 +1,67 @@
+=== tests/cases/conformance/expressions/nullishCoalescingOperator/nullishCoalescingOperator_esnext.ts ===
+// target: esnext
+
+declare const a1: 'literal' | undefined | null
+>a1 : Symbol(a1, Decl(nullishCoalescingOperator_esnext.ts, 2, 13))
+
+declare const a2: '' | undefined | null
+>a2 : Symbol(a2, Decl(nullishCoalescingOperator_esnext.ts, 3, 13))
+
+declare const a3: 1 | undefined | null
+>a3 : Symbol(a3, Decl(nullishCoalescingOperator_esnext.ts, 4, 13))
+
+declare const a4: 0 | undefined | null
+>a4 : Symbol(a4, Decl(nullishCoalescingOperator_esnext.ts, 5, 13))
+
+declare const a5: true | undefined | null
+>a5 : Symbol(a5, Decl(nullishCoalescingOperator_esnext.ts, 6, 13))
+
+declare const a6: false | undefined | null
+>a6 : Symbol(a6, Decl(nullishCoalescingOperator_esnext.ts, 7, 13))
+
+declare const a7: unknown | null
+>a7 : Symbol(a7, Decl(nullishCoalescingOperator_esnext.ts, 8, 13))
+
+declare const a8: never | null
+>a8 : Symbol(a8, Decl(nullishCoalescingOperator_esnext.ts, 9, 13))
+
+declare const a9: any | null
+>a9 : Symbol(a9, Decl(nullishCoalescingOperator_esnext.ts, 10, 13))
+
+
+const aa1 = a1 ?? 'whatever'
+>aa1 : Symbol(aa1, Decl(nullishCoalescingOperator_esnext.ts, 13, 5))
+>a1 : Symbol(a1, Decl(nullishCoalescingOperator_esnext.ts, 2, 13))
+
+const aa2 = a2 ?? 'whatever'
+>aa2 : Symbol(aa2, Decl(nullishCoalescingOperator_esnext.ts, 14, 5))
+>a2 : Symbol(a2, Decl(nullishCoalescingOperator_esnext.ts, 3, 13))
+
+const aa3 = a3 ?? 'whatever'
+>aa3 : Symbol(aa3, Decl(nullishCoalescingOperator_esnext.ts, 15, 5))
+>a3 : Symbol(a3, Decl(nullishCoalescingOperator_esnext.ts, 4, 13))
+
+const aa4 = a4 ?? 'whatever'
+>aa4 : Symbol(aa4, Decl(nullishCoalescingOperator_esnext.ts, 16, 5))
+>a4 : Symbol(a4, Decl(nullishCoalescingOperator_esnext.ts, 5, 13))
+
+const aa5 = a5 ?? 'whatever'
+>aa5 : Symbol(aa5, Decl(nullishCoalescingOperator_esnext.ts, 17, 5))
+>a5 : Symbol(a5, Decl(nullishCoalescingOperator_esnext.ts, 6, 13))
+
+const aa6 = a6 ?? 'whatever'
+>aa6 : Symbol(aa6, Decl(nullishCoalescingOperator_esnext.ts, 18, 5))
+>a6 : Symbol(a6, Decl(nullishCoalescingOperator_esnext.ts, 7, 13))
+
+const aa7 = a7 ?? 'whatever'
+>aa7 : Symbol(aa7, Decl(nullishCoalescingOperator_esnext.ts, 19, 5))
+>a7 : Symbol(a7, Decl(nullishCoalescingOperator_esnext.ts, 8, 13))
+
+const aa8 = a8 ?? 'whatever'
+>aa8 : Symbol(aa8, Decl(nullishCoalescingOperator_esnext.ts, 20, 5))
+>a8 : Symbol(a8, Decl(nullishCoalescingOperator_esnext.ts, 9, 13))
+
+const aa9 = a9 ?? 'whatever'
+>aa9 : Symbol(aa9, Decl(nullishCoalescingOperator_esnext.ts, 21, 5))
+>a9 : Symbol(a9, Decl(nullishCoalescingOperator_esnext.ts, 10, 13))
+

tests/baselines/reference/nullishCoalescingOperator_esnext.types

@@ -0,0 +1,96 @@
+=== tests/cases/conformance/expressions/nullishCoalescingOperator/nullishCoalescingOperator_esnext.ts ===
+// target: esnext
+
+declare const a1: 'literal' | undefined | null
+>a1 : "literal" | null | undefined
+>null : null
+
+declare const a2: '' | undefined | null
+>a2 : "" | null | undefined
+>null : null
+
+declare const a3: 1 | undefined | null
+>a3 : 1 | null | undefined
+>null : null
+
+declare const a4: 0 | undefined | null
+>a4 : 0 | null | undefined
+>null : null
+
+declare const a5: true | undefined | null
+>a5 : true | null | undefined
+>true : true
+>null : null
+
+declare const a6: false | undefined | null
+>a6 : false | null | undefined
+>false : false
+>null : null
+
+declare const a7: unknown | null
+>a7 : unknown
+>null : null
+
+declare const a8: never | null
+>a8 : null
+>null : null
+
+declare const a9: any | null
+>a9 : any
+>null : null
+
+
+const aa1 = a1 ?? 'whatever'
+>aa1 : "literal" | "whatever"
+>a1 ?? 'whatever' : "literal" | "whatever"
+>a1 : "literal" | null | undefined
+>'whatever' : "whatever"
+
+const aa2 = a2 ?? 'whatever'
+>aa2 : "" | "whatever"
+>a2 ?? 'whatever' : "" | "whatever"
+>a2 : "" | null | undefined
+>'whatever' : "whatever"
+
+const aa3 = a3 ?? 'whatever'
+>aa3 : 1 | "whatever"
+>a3 ?? 'whatever' : 1 | "whatever"
+>a3 : 1 | null | undefined
+>'whatever' : "whatever"
+
+const aa4 = a4 ?? 'whatever'
+>aa4 : 0 | "whatever"
+>a4 ?? 'whatever' : 0 | "whatever"
+>a4 : 0 | null | undefined
+>'whatever' : "whatever"
+
+const aa5 = a5 ?? 'whatever'
+>aa5 : true | "whatever"
+>a5 ?? 'whatever' : true | "whatever"
+>a5 : true | null | undefined
+>'whatever' : "whatever"
+
+const aa6 = a6 ?? 'whatever'
+>aa6 : false | "whatever"
+>a6 ?? 'whatever' : false | "whatever"
+>a6 : false | null | undefined
+>'whatever' : "whatever"
+
+const aa7 = a7 ?? 'whatever'
+>aa7 : unknown
+>a7 ?? 'whatever' : unknown
+>a7 : unknown
+>'whatever' : "whatever"
+
+const aa8 = a8 ?? 'whatever'
+>aa8 : "whatever"
+>a8 ?? 'whatever' : "whatever"
+>a8 : null
+>'whatever' : "whatever"
+
+const aa9 = a9 ?? 'whatever'
+>aa9 : any
+>a9 ?? 'whatever' : any
+>a9 : any
+>'whatever' : "whatever"
+

tests/baselines/reference/nullishCoalescingOperator_not_strict.js

@@ -0,0 +1,32 @@
+//// [nullishCoalescingOperator_not_strict.ts]
+declare const a1: 'literal' | undefined | null
+declare const a2: '' | undefined | null
+declare const a3: 1 | undefined | null
+declare const a4: 0 | undefined | null
+declare const a5: true | undefined | null
+declare const a6: false | undefined | null
+declare const a7: unknown | null
+declare const a8: never | null
+declare const a9: any | null
+
+
+const aa1 = a1 ?? 'whatever'
+const aa2 = a2 ?? 'whatever'
+const aa3 = a3 ?? 'whatever'
+const aa4 = a4 ?? 'whatever'
+const aa5 = a5 ?? 'whatever'
+const aa6 = a6 ?? 'whatever'
+const aa7 = a7 ?? 'whatever'
+const aa8 = a8 ?? 'whatever'
+const aa9 = a9 ?? 'whatever'
+
+//// [nullishCoalescingOperator_not_strict.js]
+var aa1 = typeof a1 !== "undefined" && a1 !== null ? a1 : 'whatever';
+var aa2 = typeof a2 !== "undefined" && a2 !== null ? a2 : 'whatever';
+var aa3 = typeof a3 !== "undefined" && a3 !== null ? a3 : 'whatever';
+var aa4 = typeof a4 !== "undefined" && a4 !== null ? a4 : 'whatever';
+var aa5 = typeof a5 !== "undefined" && a5 !== null ? a5 : 'whatever';
+var aa6 = typeof a6 !== "undefined" && a6 !== null ? a6 : 'whatever';
+var aa7 = typeof a7 !== "undefined" && a7 !== null ? a7 : 'whatever';
+var aa8 = typeof a8 !== "undefined" && a8 !== null ? a8 : 'whatever';
+var aa9 = typeof a9 !== "undefined" && a9 !== null ? a9 : 'whatever';

tests/baselines/reference/nullishCoalescingOperator_not_strict.symbols

@@ -0,0 +1,65 @@
+=== tests/cases/conformance/expressions/nullishCoalescingOperator/nullishCoalescingOperator_not_strict.ts ===
+declare const a1: 'literal' | undefined | null
+>a1 : Symbol(a1, Decl(nullishCoalescingOperator_not_strict.ts, 0, 13))
+
+declare const a2: '' | undefined | null
+>a2 : Symbol(a2, Decl(nullishCoalescingOperator_not_strict.ts, 1, 13))
+
+declare const a3: 1 | undefined | null
+>a3 : Symbol(a3, Decl(nullishCoalescingOperator_not_strict.ts, 2, 13))
+
+declare const a4: 0 | undefined | null
+>a4 : Symbol(a4, Decl(nullishCoalescingOperator_not_strict.ts, 3, 13))
+
+declare const a5: true | undefined | null
+>a5 : Symbol(a5, Decl(nullishCoalescingOperator_not_strict.ts, 4, 13))
+
+declare const a6: false | undefined | null
+>a6 : Symbol(a6, Decl(nullishCoalescingOperator_not_strict.ts, 5, 13))
+
+declare const a7: unknown | null
+>a7 : Symbol(a7, Decl(nullishCoalescingOperator_not_strict.ts, 6, 13))
+
+declare const a8: never | null
+>a8 : Symbol(a8, Decl(nullishCoalescingOperator_not_strict.ts, 7, 13))
+
+declare const a9: any | null
+>a9 : Symbol(a9, Decl(nullishCoalescingOperator_not_strict.ts, 8, 13))
+
+
+const aa1 = a1 ?? 'whatever'
+>aa1 : Symbol(aa1, Decl(nullishCoalescingOperator_not_strict.ts, 11, 5))
+>a1 : Symbol(a1, Decl(nullishCoalescingOperator_not_strict.ts, 0, 13))
+
+const aa2 = a2 ?? 'whatever'
+>aa2 : Symbol(aa2, Decl(nullishCoalescingOperator_not_strict.ts, 12, 5))
+>a2 : Symbol(a2, Decl(nullishCoalescingOperator_not_strict.ts, 1, 13))
+
+const aa3 = a3 ?? 'whatever'
+>aa3 : Symbol(aa3, Decl(nullishCoalescingOperator_not_strict.ts, 13, 5))
+>a3 : Symbol(a3, Decl(nullishCoalescingOperator_not_strict.ts, 2, 13))
+
+const aa4 = a4 ?? 'whatever'
+>aa4 : Symbol(aa4, Decl(nullishCoalescingOperator_not_strict.ts, 14, 5))
+>a4 : Symbol(a4, Decl(nullishCoalescingOperator_not_strict.ts, 3, 13))
+
+const aa5 = a5 ?? 'whatever'
+>aa5 : Symbol(aa5, Decl(nullishCoalescingOperator_not_strict.ts, 15, 5))
+>a5 : Symbol(a5, Decl(nullishCoalescingOperator_not_strict.ts, 4, 13))
+
+const aa6 = a6 ?? 'whatever'
+>aa6 : Symbol(aa6, Decl(nullishCoalescingOperator_not_strict.ts, 16, 5))
+>a6 : Symbol(a6, Decl(nullishCoalescingOperator_not_strict.ts, 5, 13))
+
+const aa7 = a7 ?? 'whatever'
+>aa7 : Symbol(aa7, Decl(nullishCoalescingOperator_not_strict.ts, 17, 5))
+>a7 : Symbol(a7, Decl(nullishCoalescingOperator_not_strict.ts, 6, 13))
+
+const aa8 = a8 ?? 'whatever'
+>aa8 : Symbol(aa8, Decl(nullishCoalescingOperator_not_strict.ts, 18, 5))
+>a8 : Symbol(a8, Decl(nullishCoalescingOperator_not_strict.ts, 7, 13))
+
+const aa9 = a9 ?? 'whatever'
+>aa9 : Symbol(aa9, Decl(nullishCoalescingOperator_not_strict.ts, 19, 5))
+>a9 : Symbol(a9, Decl(nullishCoalescingOperator_not_strict.ts, 8, 13))
+