From bdd47ef22849beab7c5de10da926c564849d3812 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Burzy=C5=84ski?= <mateuszburzynski@gmail.com>
Date: Thu, 16 Mar 2023 23:35:45 +0100
Subject: [PATCH 1/2] Rewrite getPropFromRaw slightly to surface T in the
 parameters

---
 src/compiler/commandLineParser.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index ab3909d8e2385..7508c2870407d 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -2974,7 +2974,7 @@ function parseJsonConfigFileContentWorker(
     };
 
     function getConfigFileSpecs(): ConfigFileSpecs {
-        const referencesOfRaw = getPropFromRaw<ProjectReference>("references", element => typeof element === "object", "object");
+        const referencesOfRaw = getPropFromRaw("references", (element): element is ProjectReference => typeof element === "object", "object");
         const filesSpecs = toPropValue(getSpecsFromRaw("files"));
         if (filesSpecs) {
             const hasZeroOrNoReferences = referencesOfRaw === "no-prop" || isArray(referencesOfRaw) && referencesOfRaw.length === 0;
@@ -3049,7 +3049,7 @@ function parseJsonConfigFileContentWorker(
 
     function getProjectReferences(basePath: string): readonly ProjectReference[] | undefined {
         let projectReferences: ProjectReference[] | undefined;
-        const referencesOfRaw = getPropFromRaw<ProjectReference>("references", element => typeof element === "object", "object");
+        const referencesOfRaw = getPropFromRaw("references", (element): element is ProjectReference => typeof element === "object", "object");
         if (isArray(referencesOfRaw)) {
             for (const ref of referencesOfRaw) {
                 if (typeof ref.path !== "string") {
@@ -3077,7 +3077,7 @@ function parseJsonConfigFileContentWorker(
         return getPropFromRaw(prop, isString, "string");
     }
 
-    function getPropFromRaw<T>(prop: "files" | "include" | "exclude" | "references", validateElement: (value: unknown) => boolean, elementTypeName: string): PropOfRaw<T> {
+    function getPropFromRaw<T>(prop: "files" | "include" | "exclude" | "references", validateElement: (value: unknown) => value is T, elementTypeName: string): PropOfRaw<T> {
         if (hasProperty(raw, prop) && !isNullOrUndefined(raw[prop])) {
             if (isArray(raw[prop])) {
                 const result = raw[prop] as T[];

From 29e6c4818b941df1371c6827d44831a85dce0270 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Burzy=C5=84ski?= <mateuszburzynski@gmail.com>
Date: Fri, 17 Mar 2023 08:47:52 +0100
Subject: [PATCH 2/2] Make getPropFromRaw even safer

---
 src/compiler/commandLineParser.ts | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 7508c2870407d..0ceebb399cbdb 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -29,7 +29,6 @@ import {
     emptyArray,
     endsWith,
     ensureTrailingDirectorySeparator,
-    every,
     Expression,
     extend,
     Extension,
@@ -2974,7 +2973,7 @@ function parseJsonConfigFileContentWorker(
     };
 
     function getConfigFileSpecs(): ConfigFileSpecs {
-        const referencesOfRaw = getPropFromRaw("references", (element): element is ProjectReference => typeof element === "object", "object");
+        const referencesOfRaw = getPropFromRaw("references", (element): element is ProjectReference => !!element && typeof element === "object", "object");
         const filesSpecs = toPropValue(getSpecsFromRaw("files"));
         if (filesSpecs) {
             const hasZeroOrNoReferences = referencesOfRaw === "no-prop" || isArray(referencesOfRaw) && referencesOfRaw.length === 0;
@@ -3049,7 +3048,7 @@ function parseJsonConfigFileContentWorker(
 
     function getProjectReferences(basePath: string): readonly ProjectReference[] | undefined {
         let projectReferences: ProjectReference[] | undefined;
-        const referencesOfRaw = getPropFromRaw("references", (element): element is ProjectReference => typeof element === "object", "object");
+        const referencesOfRaw = getPropFromRaw("references", (element): element is ProjectReference => !!element && typeof element === "object", "object");
         if (isArray(referencesOfRaw)) {
             for (const ref of referencesOfRaw) {
                 if (typeof ref.path !== "string") {
@@ -3079,9 +3078,10 @@ function parseJsonConfigFileContentWorker(
 
     function getPropFromRaw<T>(prop: "files" | "include" | "exclude" | "references", validateElement: (value: unknown) => value is T, elementTypeName: string): PropOfRaw<T> {
         if (hasProperty(raw, prop) && !isNullOrUndefined(raw[prop])) {
-            if (isArray(raw[prop])) {
-                const result = raw[prop] as T[];
-                if (!sourceFile && !every(result, validateElement)) {
+            const value = raw[prop];
+            if (isArray(value)) {
+                const result = filter(value, validateElement);
+                if (!sourceFile && result.length !== value.length) {
                     errors.push(createCompilerDiagnostic(Diagnostics.Compiler_option_0_requires_a_value_of_type_1, prop, elementTypeName));
                 }
                 return result;