From 892936f4a18ded0216ae1c805a9890ebb8572fe3 Mon Sep 17 00:00:00 2001
From: TypeScript Bot <ts_bot@rcavanaugh.com>
Date: Tue, 9 Apr 2024 12:10:17 -0700
Subject: [PATCH] =?UTF-8?q?=F0=9F=A4=96=20Pick=20PR=20#58083=20(Don't=20pr?=
 =?UTF-8?q?opagate=20partial=20union/inter...)=20into=20release-5.4=20(#58?=
 =?UTF-8?q?136)?=
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Co-authored-by: Anders Hejlsberg <andersh@microsoft.com>
---
 src/compiler/checker.ts                       |  8 ++--
 ...ialUnionPropertyCacheInconsistentErrors.ts | 45 +++++++++++++++++++
 2 files changed, 50 insertions(+), 3 deletions(-)
 create mode 100644 tests/cases/fourslash/partialUnionPropertyCacheInconsistentErrors.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 175caa9eef16e..c3d194211c56a 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -14788,8 +14788,9 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     // these partial properties when identifying discriminant properties, but otherwise they are filtered out
     // and do not appear to be present in the union type.
     function getUnionOrIntersectionProperty(type: UnionOrIntersectionType, name: __String, skipObjectFunctionPropertyAugment?: boolean): Symbol | undefined {
-        let property = type.propertyCacheWithoutObjectFunctionPropertyAugment?.get(name) ||
-                !skipObjectFunctionPropertyAugment ? type.propertyCache?.get(name) : undefined;
+        let property = skipObjectFunctionPropertyAugment ?
+            type.propertyCacheWithoutObjectFunctionPropertyAugment?.get(name) :
+            type.propertyCache?.get(name);
         if (!property) {
             property = createUnionOrIntersectionProperty(type, name, skipObjectFunctionPropertyAugment);
             if (property) {
@@ -14797,7 +14798,8 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                     type.propertyCacheWithoutObjectFunctionPropertyAugment ||= createSymbolTable() :
                     type.propertyCache ||= createSymbolTable();
                 properties.set(name, property);
-                if (skipObjectFunctionPropertyAugment && !type.propertyCache?.get(name)) {
+                // Propagate an entry from the non-augmented cache to the augmented cache unless the property is partial.
+                if (skipObjectFunctionPropertyAugment && !(getCheckFlags(property) & CheckFlags.Partial) && !type.propertyCache?.get(name)) {
                     const properties = type.propertyCache ||= createSymbolTable();
                     properties.set(name, property);
                 }
diff --git a/tests/cases/fourslash/partialUnionPropertyCacheInconsistentErrors.ts b/tests/cases/fourslash/partialUnionPropertyCacheInconsistentErrors.ts
new file mode 100644
index 0000000000000..7d793b520fa05
--- /dev/null
+++ b/tests/cases/fourslash/partialUnionPropertyCacheInconsistentErrors.ts
@@ -0,0 +1,45 @@
+/// <reference path="fourslash.ts" />
+
+// @strict: true
+// @lib: esnext
+
+//// interface ComponentOptions<Props> {
+////   setup?: (props: Props) => void;
+////   name?: string;
+//// }
+//// 
+//// interface FunctionalComponent<P> {
+////   (props: P): void;
+//// }
+//// 
+//// type ConcreteComponent<Props> =
+////   | ComponentOptions<Props>
+////   | FunctionalComponent<Props>;
+//// 
+//// type Component<Props = {}> = ConcreteComponent<Props>;
+//// 
+//// type WithInstallPlugin = { _prefix?: string };
+//// 
+//// 
+//// /**/
+//// export function withInstall<C extends Component, T extends WithInstallPlugin>(
+////   component: C | C[],
+////   target?: T,
+//// ): string {
+////   const componentWithInstall = (target ?? component) as T;
+////   const components = Array.isArray(component) ? component : [component];
+//// 
+////   const { name } = components[0];
+////   if (name) {
+////     return name;
+////   }
+//// 
+////   return "";
+//// }
+
+verify.noErrors();
+
+goTo.marker();
+edit.insert("type C = Component['name']");
+
+verify.noErrors();
\ No newline at end of file