Fix diagnostic serialization crash (#47604)

* Add crashing test

* Fix unsafe cast to DiagnosticMessageChain

src/compiler/checker.ts

@@ -30121,7 +30121,7 @@ namespace ts {
                         const diags = max > 1 ? allDiagnostics[minIndex] : flatten(allDiagnostics);
                         Debug.assert(diags.length > 0, "No errors reported for 3 or fewer overload signatures");
                         const chain = chainDiagnosticMessages(
-                            map(diags, d => typeof d.messageText === "string" ? (d as DiagnosticMessageChain) : d.messageText),
+                            map(diags, createDiagnosticMessageChainFromDiagnostic),
                             Diagnostics.No_overload_matches_this_call);
                         // The below is a spread to guarantee we get a new (mutable) array - our `flatMap` helper tries to do "smart" optimizations where it reuses input
                         // arrays and the emptyArray singleton where possible, which is decidedly not what we want while we're still constructing this diagnostic

src/compiler/utilities.ts

@@ -1071,6 +1071,15 @@ namespace ts {
         };
     }
 
+    export function createDiagnosticMessageChainFromDiagnostic(diagnostic: DiagnosticRelatedInformation): DiagnosticMessageChain {
+        return typeof diagnostic.messageText === "string" ? {
+            code: diagnostic.code,
+            category: diagnostic.category,
+            messageText: diagnostic.messageText,
+            next: (diagnostic as DiagnosticMessageChain).next,
+        } : diagnostic.messageText;
+    }
+
     export function createDiagnosticForRange(sourceFile: SourceFile, range: TextRange, message: DiagnosticMessage): DiagnosticWithLocation {
         return {
             file: sourceFile,

src/testRunner/unittests/tsc/incremental.ts

@@ -418,5 +418,36 @@ declare global {
             incrementalScenarios: noChangeOnlyRuns,
             baselinePrograms: true
         });
+
+        verifyTscSerializedIncrementalEdits({
+            scenario: "incremental",
+            subScenario: "serializing error chains",
+            commandLineArgs: ["-p", `src/project`],
+            fs: () => loadProjectFromFiles({
+                "/src/project/tsconfig.json": JSON.stringify({
+                    compilerOptions: {
+                        incremental: true,
+                        strict: true,
+                        jsx: "react",
+                        module: "esnext",
+                    },
+                }),
+                "/src/project/index.tsx": Utils.dedent`
+                    declare namespace JSX {
+                        interface ElementChildrenAttribute { children: {}; }
+                        interface IntrinsicElements { div: {} }
+                    }
+
+                    declare var React: any;
+
+                    declare function Component(props: never): any;
+                    declare function Component(props: { children?: number }): any;
+                    (<Component>
+                        <div />
+                        <div />
+                    </Component>)`
+            }, `\ninterface ReadonlyArray<T> { readonly length: number }`),
+            incrementalScenarios: noChangeOnlyRuns,
+        });
     });
 }