From e0e45ec46cf4c4b80bf65e6a22eb784aa78016eb Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 17 Dec 2019 13:10:06 -0800
Subject: [PATCH] Accept new baselines

---
 .../reference/unionTypeReduction2.errors.txt  |  72 +++++
 .../reference/unionTypeReduction2.js          | 110 ++++++++
 .../reference/unionTypeReduction2.symbols     | 203 ++++++++++++++
 .../reference/unionTypeReduction2.types       | 250 ++++++++++++++++++
 4 files changed, 635 insertions(+)
 create mode 100644 tests/baselines/reference/unionTypeReduction2.errors.txt
 create mode 100644 tests/baselines/reference/unionTypeReduction2.js
 create mode 100644 tests/baselines/reference/unionTypeReduction2.symbols
 create mode 100644 tests/baselines/reference/unionTypeReduction2.types

diff --git a/tests/baselines/reference/unionTypeReduction2.errors.txt b/tests/baselines/reference/unionTypeReduction2.errors.txt
new file mode 100644
index 00000000000..74567f8808b
--- /dev/null
+++ b/tests/baselines/reference/unionTypeReduction2.errors.txt
@@ -0,0 +1,72 @@
+tests/cases/conformance/types/union/unionTypeReduction2.ts(33,5): error TS2554: Expected 1 arguments, but got 0.
+
+
+==== tests/cases/conformance/types/union/unionTypeReduction2.ts (1 errors) ====
+    function f1(x: { f(): void }, y: { f(x?: string): void }) {
+        let z = !!true ? x : y;  // { f(x?: string): void }
+        z.f();
+        z.f('hello');
+    }
+    
+    function f2(x: { f(x: string | undefined): void }, y: { f(x?: string): void }) {
+        let z = !!true ? x : y;  // { f(x?: string): void }
+        z.f();
+        z.f('hello');
+    }
+    
+    function f3(x: () => void, y: (x?: string) => void) {
+        let f = !!true ? x : y;  // (x?: string) => void
+        f();
+        f('hello');
+    }
+    
+    function f4(x: (x: string | undefined) => void, y: (x?: string) => void) {
+        let f = !!true ? x : y;  // (x?: string) => void
+        f();
+        f('hello');
+    }
+    
+    function f5(x: (x: string | undefined) => void, y: (x?: 'hello') => void) {
+        let f = !!true ? x : y;  // (x?: 'hello') => void
+        f();
+        f('hello');
+    }
+    
+    function f6(x: (x: 'hello' | undefined) => void, y: (x?: string) => void) {
+        let f = !!true ? x : y;  // (x: 'hello' | undefined) => void
+        f();  // Error
+        ~~~
+!!! error TS2554: Expected 1 arguments, but got 0.
+!!! related TS6210 tests/cases/conformance/types/union/unionTypeReduction2.ts:31:17: An argument for 'x' was not provided.
+        f('hello');
+    }
+    
+    type A = {
+        f(): void;
+    }
+    
+    type B = {
+        f(x?: string): void;
+        g(): void;
+    }
+    
+    function f11(a: A, b: B) {
+        let z = !!true ? a : b;  // A | B
+        z.f();
+        z.f('hello');
+    }
+    
+    // Repro from #35414
+    
+    interface ReturnVal {
+        something(): void;
+    }
+    
+    const k: ReturnVal = { something() { } }
+    
+    declare const val: ReturnVal;
+    function run(options: { something?(b?: string): void }) {
+        const something = options.something ?? val.something;
+        something('');
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/unionTypeReduction2.js b/tests/baselines/reference/unionTypeReduction2.js
new file mode 100644
index 00000000000..3749b9c8cf5
--- /dev/null
+++ b/tests/baselines/reference/unionTypeReduction2.js
@@ -0,0 +1,110 @@
+//// [unionTypeReduction2.ts]
+function f1(x: { f(): void }, y: { f(x?: string): void }) {
+    let z = !!true ? x : y;  // { f(x?: string): void }
+    z.f();
+    z.f('hello');
+}
+
+function f2(x: { f(x: string | undefined): void }, y: { f(x?: string): void }) {
+    let z = !!true ? x : y;  // { f(x?: string): void }
+    z.f();
+    z.f('hello');
+}
+
+function f3(x: () => void, y: (x?: string) => void) {
+    let f = !!true ? x : y;  // (x?: string) => void
+    f();
+    f('hello');
+}
+
+function f4(x: (x: string | undefined) => void, y: (x?: string) => void) {
+    let f = !!true ? x : y;  // (x?: string) => void
+    f();
+    f('hello');
+}
+
+function f5(x: (x: string | undefined) => void, y: (x?: 'hello') => void) {
+    let f = !!true ? x : y;  // (x?: 'hello') => void
+    f();
+    f('hello');
+}
+
+function f6(x: (x: 'hello' | undefined) => void, y: (x?: string) => void) {
+    let f = !!true ? x : y;  // (x: 'hello' | undefined) => void
+    f();  // Error
+    f('hello');
+}
+
+type A = {
+    f(): void;
+}
+
+type B = {
+    f(x?: string): void;
+    g(): void;
+}
+
+function f11(a: A, b: B) {
+    let z = !!true ? a : b;  // A | B
+    z.f();
+    z.f('hello');
+}
+
+// Repro from #35414
+
+interface ReturnVal {
+    something(): void;
+}
+
+const k: ReturnVal = { something() { } }
+
+declare const val: ReturnVal;
+function run(options: { something?(b?: string): void }) {
+    const something = options.something ?? val.something;
+    something('');
+}
+
+
+//// [unionTypeReduction2.js]
+"use strict";
+function f1(x, y) {
+    var z = !!true ? x : y; // { f(x?: string): void }
+    z.f();
+    z.f('hello');
+}
+function f2(x, y) {
+    var z = !!true ? x : y; // { f(x?: string): void }
+    z.f();
+    z.f('hello');
+}
+function f3(x, y) {
+    var f = !!true ? x : y; // (x?: string) => void
+    f();
+    f('hello');
+}
+function f4(x, y) {
+    var f = !!true ? x : y; // (x?: string) => void
+    f();
+    f('hello');
+}
+function f5(x, y) {
+    var f = !!true ? x : y; // (x?: 'hello') => void
+    f();
+    f('hello');
+}
+function f6(x, y) {
+    var f = !!true ? x : y; // (x: 'hello' | undefined) => void
+    f(); // Error
+    f('hello');
+}
+function f11(a, b) {
+    var z = !!true ? a : b; // A | B
+    z.f();
+    z.f('hello');
+}
+var k = { something: function () { } };
+function run(options) {
+    var _a;
+    var something = (_a = options.something) !== null && _a !== void 0 ? _a : val.something;
+    something('');
+}
diff --git a/tests/baselines/reference/unionTypeReduction2.symbols b/tests/baselines/reference/unionTypeReduction2.symbols
new file mode 100644
index 00000000000..0faf0055279
--- /dev/null
+++ b/tests/baselines/reference/unionTypeReduction2.symbols
@@ -0,0 +1,203 @@
+=== tests/cases/conformance/types/union/unionTypeReduction2.ts ===
+function f1(x: { f(): void }, y: { f(x?: string): void }) {
+>f1 : Symbol(f1, Decl(unionTypeReduction2.ts, 0, 0))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 0, 12))
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 0, 16))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 0, 29))
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 0, 34))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 0, 37))
+
+    let z = !!true ? x : y;  // { f(x?: string): void }
+>z : Symbol(z, Decl(unionTypeReduction2.ts, 1, 7))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 0, 12))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 0, 29))
+
+    z.f();
+>z.f : Symbol(f, Decl(unionTypeReduction2.ts, 0, 34))
+>z : Symbol(z, Decl(unionTypeReduction2.ts, 1, 7))
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 0, 34))
+
+    z.f('hello');
+>z.f : Symbol(f, Decl(unionTypeReduction2.ts, 0, 34))
+>z : Symbol(z, Decl(unionTypeReduction2.ts, 1, 7))
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 0, 34))
+}
+
+function f2(x: { f(x: string | undefined): void }, y: { f(x?: string): void }) {
+>f2 : Symbol(f2, Decl(unionTypeReduction2.ts, 4, 1))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 6, 12))
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 6, 16))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 6, 19))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 6, 50))
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 6, 55))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 6, 58))
+
+    let z = !!true ? x : y;  // { f(x?: string): void }
+>z : Symbol(z, Decl(unionTypeReduction2.ts, 7, 7))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 6, 12))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 6, 50))
+
+    z.f();
+>z.f : Symbol(f, Decl(unionTypeReduction2.ts, 6, 55))
+>z : Symbol(z, Decl(unionTypeReduction2.ts, 7, 7))
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 6, 55))
+
+    z.f('hello');
+>z.f : Symbol(f, Decl(unionTypeReduction2.ts, 6, 55))
+>z : Symbol(z, Decl(unionTypeReduction2.ts, 7, 7))
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 6, 55))
+}
+
+function f3(x: () => void, y: (x?: string) => void) {
+>f3 : Symbol(f3, Decl(unionTypeReduction2.ts, 10, 1))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 12, 12))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 12, 26))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 12, 31))
+
+    let f = !!true ? x : y;  // (x?: string) => void
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 13, 7))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 12, 12))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 12, 26))
+
+    f();
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 13, 7))
+
+    f('hello');
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 13, 7))
+}
+
+function f4(x: (x: string | undefined) => void, y: (x?: string) => void) {
+>f4 : Symbol(f4, Decl(unionTypeReduction2.ts, 16, 1))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 18, 12))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 18, 16))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 18, 47))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 18, 52))
+
+    let f = !!true ? x : y;  // (x?: string) => void
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 19, 7))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 18, 12))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 18, 47))
+
+    f();
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 19, 7))
+
+    f('hello');
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 19, 7))
+}
+
+function f5(x: (x: string | undefined) => void, y: (x?: 'hello') => void) {
+>f5 : Symbol(f5, Decl(unionTypeReduction2.ts, 22, 1))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 24, 12))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 24, 16))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 24, 47))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 24, 52))
+
+    let f = !!true ? x : y;  // (x?: 'hello') => void
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 25, 7))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 24, 12))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 24, 47))
+
+    f();
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 25, 7))
+
+    f('hello');
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 25, 7))
+}
+
+function f6(x: (x: 'hello' | undefined) => void, y: (x?: string) => void) {
+>f6 : Symbol(f6, Decl(unionTypeReduction2.ts, 28, 1))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 30, 12))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 30, 16))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 30, 48))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 30, 53))
+
+    let f = !!true ? x : y;  // (x: 'hello' | undefined) => void
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 31, 7))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 30, 12))
+>y : Symbol(y, Decl(unionTypeReduction2.ts, 30, 48))
+
+    f();  // Error
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 31, 7))
+
+    f('hello');
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 31, 7))
+}
+
+type A = {
+>A : Symbol(A, Decl(unionTypeReduction2.ts, 34, 1))
+
+    f(): void;
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 36, 10))
+}
+
+type B = {
+>B : Symbol(B, Decl(unionTypeReduction2.ts, 38, 1))
+
+    f(x?: string): void;
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 40, 10))
+>x : Symbol(x, Decl(unionTypeReduction2.ts, 41, 6))
+
+    g(): void;
+>g : Symbol(g, Decl(unionTypeReduction2.ts, 41, 24))
+}
+
+function f11(a: A, b: B) {
+>f11 : Symbol(f11, Decl(unionTypeReduction2.ts, 43, 1))
+>a : Symbol(a, Decl(unionTypeReduction2.ts, 45, 13))
+>A : Symbol(A, Decl(unionTypeReduction2.ts, 34, 1))
+>b : Symbol(b, Decl(unionTypeReduction2.ts, 45, 18))
+>B : Symbol(B, Decl(unionTypeReduction2.ts, 38, 1))
+
+    let z = !!true ? a : b;  // A | B
+>z : Symbol(z, Decl(unionTypeReduction2.ts, 46, 7))
+>a : Symbol(a, Decl(unionTypeReduction2.ts, 45, 13))
+>b : Symbol(b, Decl(unionTypeReduction2.ts, 45, 18))
+
+    z.f();
+>z.f : Symbol(f, Decl(unionTypeReduction2.ts, 36, 10), Decl(unionTypeReduction2.ts, 40, 10))
+>z : Symbol(z, Decl(unionTypeReduction2.ts, 46, 7))
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 36, 10), Decl(unionTypeReduction2.ts, 40, 10))
+
+    z.f('hello');
+>z.f : Symbol(f, Decl(unionTypeReduction2.ts, 36, 10), Decl(unionTypeReduction2.ts, 40, 10))
+>z : Symbol(z, Decl(unionTypeReduction2.ts, 46, 7))
+>f : Symbol(f, Decl(unionTypeReduction2.ts, 36, 10), Decl(unionTypeReduction2.ts, 40, 10))
+}
+
+// Repro from #35414
+
+interface ReturnVal {
+>ReturnVal : Symbol(ReturnVal, Decl(unionTypeReduction2.ts, 49, 1))
+
+    something(): void;
+>something : Symbol(ReturnVal.something, Decl(unionTypeReduction2.ts, 53, 21))
+}
+
+const k: ReturnVal = { something() { } }
+>k : Symbol(k, Decl(unionTypeReduction2.ts, 57, 5))
+>ReturnVal : Symbol(ReturnVal, Decl(unionTypeReduction2.ts, 49, 1))
+>something : Symbol(something, Decl(unionTypeReduction2.ts, 57, 22))
+
+declare const val: ReturnVal;
+>val : Symbol(val, Decl(unionTypeReduction2.ts, 59, 13))
+>ReturnVal : Symbol(ReturnVal, Decl(unionTypeReduction2.ts, 49, 1))
+
+function run(options: { something?(b?: string): void }) {
+>run : Symbol(run, Decl(unionTypeReduction2.ts, 59, 29))
+>options : Symbol(options, Decl(unionTypeReduction2.ts, 60, 13))
+>something : Symbol(something, Decl(unionTypeReduction2.ts, 60, 23))
+>b : Symbol(b, Decl(unionTypeReduction2.ts, 60, 35))
+
+    const something = options.something ?? val.something;
+>something : Symbol(something, Decl(unionTypeReduction2.ts, 61, 9))
+>options.something : Symbol(something, Decl(unionTypeReduction2.ts, 60, 23))
+>options : Symbol(options, Decl(unionTypeReduction2.ts, 60, 13))
+>something : Symbol(something, Decl(unionTypeReduction2.ts, 60, 23))
+>val.something : Symbol(ReturnVal.something, Decl(unionTypeReduction2.ts, 53, 21))
+>val : Symbol(val, Decl(unionTypeReduction2.ts, 59, 13))
+>something : Symbol(ReturnVal.something, Decl(unionTypeReduction2.ts, 53, 21))
+
+    something('');
+>something : Symbol(something, Decl(unionTypeReduction2.ts, 61, 9))
+}
+
diff --git a/tests/baselines/reference/unionTypeReduction2.types b/tests/baselines/reference/unionTypeReduction2.types
new file mode 100644
index 00000000000..5342ab692ab
--- /dev/null
+++ b/tests/baselines/reference/unionTypeReduction2.types
@@ -0,0 +1,250 @@
+=== tests/cases/conformance/types/union/unionTypeReduction2.ts ===
+function f1(x: { f(): void }, y: { f(x?: string): void }) {
+>f1 : (x: { f(): void; }, y: { f(x?: string | undefined): void; }) => void
+>x : { f(): void; }
+>f : () => void
+>y : { f(x?: string | undefined): void; }
+>f : (x?: string | undefined) => void
+>x : string | undefined
+
+    let z = !!true ? x : y;  // { f(x?: string): void }
+>z : { f(x?: string | undefined): void; }
+>!!true ? x : y : { f(x?: string | undefined): void; }
+>!!true : true
+>!true : false
+>true : true
+>x : { f(): void; }
+>y : { f(x?: string | undefined): void; }
+
+    z.f();
+>z.f() : void
+>z.f : (x?: string | undefined) => void
+>z : { f(x?: string | undefined): void; }
+>f : (x?: string | undefined) => void
+
+    z.f('hello');
+>z.f('hello') : void
+>z.f : (x?: string | undefined) => void
+>z : { f(x?: string | undefined): void; }
+>f : (x?: string | undefined) => void
+>'hello' : "hello"
+}
+
+function f2(x: { f(x: string | undefined): void }, y: { f(x?: string): void }) {
+>f2 : (x: { f(x: string | undefined): void; }, y: { f(x?: string | undefined): void; }) => void
+>x : { f(x: string | undefined): void; }
+>f : (x: string | undefined) => void
+>x : string | undefined
+>y : { f(x?: string | undefined): void; }
+>f : (x?: string | undefined) => void
+>x : string | undefined
+
+    let z = !!true ? x : y;  // { f(x?: string): void }
+>z : { f(x?: string | undefined): void; }
+>!!true ? x : y : { f(x?: string | undefined): void; }
+>!!true : true
+>!true : false
+>true : true
+>x : { f(x: string | undefined): void; }
+>y : { f(x?: string | undefined): void; }
+
+    z.f();
+>z.f() : void
+>z.f : (x?: string | undefined) => void
+>z : { f(x?: string | undefined): void; }
+>f : (x?: string | undefined) => void
+
+    z.f('hello');
+>z.f('hello') : void
+>z.f : (x?: string | undefined) => void
+>z : { f(x?: string | undefined): void; }
+>f : (x?: string | undefined) => void
+>'hello' : "hello"
+}
+
+function f3(x: () => void, y: (x?: string) => void) {
+>f3 : (x: () => void, y: (x?: string | undefined) => void) => void
+>x : () => void
+>y : (x?: string | undefined) => void
+>x : string | undefined
+
+    let f = !!true ? x : y;  // (x?: string) => void
+>f : (x?: string | undefined) => void
+>!!true ? x : y : (x?: string | undefined) => void
+>!!true : true
+>!true : false
+>true : true
+>x : () => void
+>y : (x?: string | undefined) => void
+
+    f();
+>f() : void
+>f : (x?: string | undefined) => void
+
+    f('hello');
+>f('hello') : void
+>f : (x?: string | undefined) => void
+>'hello' : "hello"
+}
+
+function f4(x: (x: string | undefined) => void, y: (x?: string) => void) {
+>f4 : (x: (x: string | undefined) => void, y: (x?: string | undefined) => void) => void
+>x : (x: string | undefined) => void
+>x : string | undefined
+>y : (x?: string | undefined) => void
+>x : string | undefined
+
+    let f = !!true ? x : y;  // (x?: string) => void
+>f : (x?: string | undefined) => void
+>!!true ? x : y : (x?: string | undefined) => void
+>!!true : true
+>!true : false
+>true : true
+>x : (x: string | undefined) => void
+>y : (x?: string | undefined) => void
+
+    f();
+>f() : void
+>f : (x?: string | undefined) => void
+
+    f('hello');
+>f('hello') : void
+>f : (x?: string | undefined) => void
+>'hello' : "hello"
+}
+
+function f5(x: (x: string | undefined) => void, y: (x?: 'hello') => void) {
+>f5 : (x: (x: string | undefined) => void, y: (x?: "hello" | undefined) => void) => void
+>x : (x: string | undefined) => void
+>x : string | undefined
+>y : (x?: "hello" | undefined) => void
+>x : "hello" | undefined
+
+    let f = !!true ? x : y;  // (x?: 'hello') => void
+>f : (x?: "hello" | undefined) => void
+>!!true ? x : y : (x?: "hello" | undefined) => void
+>!!true : true
+>!true : false
+>true : true
+>x : (x: string | undefined) => void
+>y : (x?: "hello" | undefined) => void
+
+    f();
+>f() : void
+>f : (x?: "hello" | undefined) => void
+
+    f('hello');
+>f('hello') : void
+>f : (x?: "hello" | undefined) => void
+>'hello' : "hello"
+}
+
+function f6(x: (x: 'hello' | undefined) => void, y: (x?: string) => void) {
+>f6 : (x: (x: "hello" | undefined) => void, y: (x?: string | undefined) => void) => void
+>x : (x: "hello" | undefined) => void
+>x : "hello" | undefined
+>y : (x?: string | undefined) => void
+>x : string | undefined
+
+    let f = !!true ? x : y;  // (x: 'hello' | undefined) => void
+>f : (x: "hello" | undefined) => void
+>!!true ? x : y : (x: "hello" | undefined) => void
+>!!true : true
+>!true : false
+>true : true
+>x : (x: "hello" | undefined) => void
+>y : (x?: string | undefined) => void
+
+    f();  // Error
+>f() : void
+>f : (x: "hello" | undefined) => void
+
+    f('hello');
+>f('hello') : void
+>f : (x: "hello" | undefined) => void
+>'hello' : "hello"
+}
+
+type A = {
+>A : A
+
+    f(): void;
+>f : () => void
+}
+
+type B = {
+>B : B
+
+    f(x?: string): void;
+>f : (x?: string | undefined) => void
+>x : string | undefined
+
+    g(): void;
+>g : () => void
+}
+
+function f11(a: A, b: B) {
+>f11 : (a: A, b: B) => void
+>a : A
+>b : B
+
+    let z = !!true ? a : b;  // A | B
+>z : A | B
+>!!true ? a : b : A | B
+>!!true : true
+>!true : false
+>true : true
+>a : A
+>b : B
+
+    z.f();
+>z.f() : void
+>z.f : ((x?: string | undefined) => void) | (() => void)
+>z : A | B
+>f : ((x?: string | undefined) => void) | (() => void)
+
+    z.f('hello');
+>z.f('hello') : void
+>z.f : ((x?: string | undefined) => void) | (() => void)
+>z : A | B
+>f : ((x?: string | undefined) => void) | (() => void)
+>'hello' : "hello"
+}
+
+// Repro from #35414
+
+interface ReturnVal {
+    something(): void;
+>something : () => void
+}
+
+const k: ReturnVal = { something() { } }
+>k : ReturnVal
+>{ something() { } } : { something(): void; }
+>something : () => void
+
+declare const val: ReturnVal;
+>val : ReturnVal
+
+function run(options: { something?(b?: string): void }) {
+>run : (options: { something?(b?: string | undefined): void; }) => void
+>options : { something?(b?: string | undefined): void; }
+>something : ((b?: string | undefined) => void) | undefined
+>b : string | undefined
+
+    const something = options.something ?? val.something;
+>something : (b?: string | undefined) => void
+>options.something ?? val.something : (b?: string | undefined) => void
+>options.something : ((b?: string | undefined) => void) | undefined
+>options : { something?(b?: string | undefined): void; }
+>something : ((b?: string | undefined) => void) | undefined
+>val.something : () => void
+>val : ReturnVal
+>something : () => void
+
+    something('');
+>something('') : void
+>something : (b?: string | undefined) => void
+>'' : ""
+}
+