Merge pull request #18925 from Microsoft/fix-spread-contextually-typed-by-binding-pattern

Fix object spread that is contextually typed by a binding pattern

src/compiler/checker.ts

@@ -14200,7 +14200,7 @@ namespace ts {
             // type with those properties for which the binding pattern specifies a default value.
             if (contextualTypeHasPattern) {
                 for (const prop of getPropertiesOfType(contextualType)) {
-                    if (!propertiesTable.get(prop.escapedName)) {
+                    if (!propertiesTable.get(prop.escapedName) && !(spread && getPropertyOfType(spread, prop.escapedName))) {
                         if (!(prop.flags & SymbolFlags.Optional)) {
                             error(prop.valueDeclaration || (<TransientSymbol>prop).bindingElement,
                                 Diagnostics.Initializer_provides_no_value_for_this_binding_element_and_the_binding_element_has_no_default_value);

tests/baselines/reference/spreadContextualTypedBindingPattern.js

@@ -0,0 +1,25 @@
+//// [spreadContextualTypedBindingPattern.ts]
+// #18308
+interface Person {
+  naam: string,
+  age: number
+}
+
+declare const bob: Person
+declare const alice: Person
+
+// [ts] Initializer provides no value for this binding element and the binding element has no default value.
+const { naam, age } = {...bob, ...alice}
+
+
+//// [spreadContextualTypedBindingPattern.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var s, i = 1, n = arguments.length; i < n; i++) {
+        s = arguments[i];
+        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+            t[p] = s[p];
+    }
+    return t;
+};
+// [ts] Initializer provides no value for this binding element and the binding element has no default value.
+var _a = __assign({}, bob, alice), naam = _a.naam, age = _a.age;

tests/baselines/reference/spreadContextualTypedBindingPattern.symbols

@@ -0,0 +1,27 @@
+=== tests/cases/conformance/types/spread/spreadContextualTypedBindingPattern.ts ===
+// #18308
+interface Person {
+>Person : Symbol(Person, Decl(spreadContextualTypedBindingPattern.ts, 0, 0))
+
+  naam: string,
+>naam : Symbol(Person.naam, Decl(spreadContextualTypedBindingPattern.ts, 1, 18))
+
+  age: number
+>age : Symbol(Person.age, Decl(spreadContextualTypedBindingPattern.ts, 2, 15))
+}
+
+declare const bob: Person
+>bob : Symbol(bob, Decl(spreadContextualTypedBindingPattern.ts, 6, 13))
+>Person : Symbol(Person, Decl(spreadContextualTypedBindingPattern.ts, 0, 0))
+
+declare const alice: Person
+>alice : Symbol(alice, Decl(spreadContextualTypedBindingPattern.ts, 7, 13))
+>Person : Symbol(Person, Decl(spreadContextualTypedBindingPattern.ts, 0, 0))
+
+// [ts] Initializer provides no value for this binding element and the binding element has no default value.
+const { naam, age } = {...bob, ...alice}
+>naam : Symbol(naam, Decl(spreadContextualTypedBindingPattern.ts, 10, 7))
+>age : Symbol(age, Decl(spreadContextualTypedBindingPattern.ts, 10, 13))
+>bob : Symbol(bob, Decl(spreadContextualTypedBindingPattern.ts, 6, 13))
+>alice : Symbol(alice, Decl(spreadContextualTypedBindingPattern.ts, 7, 13))
+

tests/baselines/reference/spreadContextualTypedBindingPattern.types

@@ -0,0 +1,28 @@
+=== tests/cases/conformance/types/spread/spreadContextualTypedBindingPattern.ts ===
+// #18308
+interface Person {
+>Person : Person
+
+  naam: string,
+>naam : string
+
+  age: number
+>age : number
+}
+
+declare const bob: Person
+>bob : Person
+>Person : Person
+
+declare const alice: Person
+>alice : Person
+>Person : Person
+
+// [ts] Initializer provides no value for this binding element and the binding element has no default value.
+const { naam, age } = {...bob, ...alice}
+>naam : string
+>age : number
+>{...bob, ...alice} : { naam: string; age: number; }
+>bob : Person
+>alice : Person
+

tests/cases/conformance/types/spread/spreadContextualTypedBindingPattern.ts

@@ -0,0 +1,11 @@
+// #18308
+interface Person {
+  naam: string,
+  age: number
+}
+
+declare const bob: Person
+declare const alice: Person
+
+// [ts] Initializer provides no value for this binding element and the binding element has no default value.
+const { naam, age } = {...bob, ...alice}