Turn this into a proper flag

Author: jakebailey

src/compiler/checker.ts

@@ -1083,7 +1083,6 @@ import {
     tryGetModuleSpecifierFromDeclaration,
     tryGetPropertyAccessOrIdentifierToString,
     TryStatement,
-    TSGO_COMPAT,
     TupleType,
     TupleTypeNode,
     TupleTypeReference,
@@ -1543,6 +1542,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     var useUnknownInCatchVariables = getStrictOptionValue(compilerOptions, "useUnknownInCatchVariables");
     var exactOptionalPropertyTypes = compilerOptions.exactOptionalPropertyTypes;
     var noUncheckedSideEffectImports = compilerOptions.noUncheckedSideEffectImports !== false;
+    var stableTypeOrdering = compilerOptions.stableTypeOrdering !== false;
 
     var checkBinaryExpression = createCheckBinaryExpression();
     var emitResolver = createResolver();
@@ -5559,7 +5559,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function createTypeofType() {
-        return getUnionType(map(TSGO_COMPAT ? [...typeofNEFacts.keys()].sort() : arrayFrom(typeofNEFacts.keys()), getStringLiteralType));
+        return getUnionType(map(stableTypeOrdering ? [...typeofNEFacts.keys()].sort() : arrayFrom(typeofNEFacts.keys()), getStringLiteralType));
     }
 
     function createTypeParameter(symbol?: Symbol) {
@@ -5579,7 +5579,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function getNamedMembers(members: SymbolTable, container: Symbol | undefined): Symbol[] {
-        if (!TSGO_COMPAT) {
+        if (!stableTypeOrdering) {
             let result: Symbol[] | undefined;
             members.forEach((symbol, id) => {
                 if (isNamedMember(symbol, id)) {
@@ -18072,11 +18072,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function containsType(types: readonly Type[], type: Type): boolean {
-        return TSGO_COMPAT ? binarySearch(types, type, identity, compareTypes) >= 0 : binarySearch(types, type, getTypeId, compareValues) >= 0;
+        return stableTypeOrdering ? binarySearch(types, type, identity, compareTypes) >= 0 : binarySearch(types, type, getTypeId, compareValues) >= 0;
     }
 
     function insertType(types: Type[], type: Type): boolean {
-        const index = TSGO_COMPAT ? binarySearch(types, type, identity, compareTypes) : binarySearch(types, type, getTypeId, compareValues);
+        const index = stableTypeOrdering ? binarySearch(types, type, identity, compareTypes) : binarySearch(types, type, getTypeId, compareValues);
         if (index < 0) {
             types.splice(~index, 0, type);
             return true;
@@ -18098,7 +18098,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             }
             else {
                 const len = typeSet.length;
-                const index = TSGO_COMPAT ? binarySearch(typeSet, type, identity, compareTypes) : (len && type.id > typeSet[len - 1].id ? ~len : binarySearch(typeSet, type, getTypeId, compareValues));
+                const index = stableTypeOrdering ? binarySearch(typeSet, type, identity, compareTypes) : (len && type.id > typeSet[len - 1].id ? ~len : binarySearch(typeSet, type, getTypeId, compareValues));
                 if (index < 0) {
                     typeSet.splice(~index, 0, type);
                 }
@@ -53787,7 +53787,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     function sortSymbolsIfTSGoCompat(array: Symbol[]): Symbol[];
     function sortSymbolsIfTSGoCompat(array: Symbol[] | undefined): Symbol[] | undefined;
     function sortSymbolsIfTSGoCompat(array: Symbol[] | undefined): Symbol[] | undefined {
-        if (TSGO_COMPAT && array) {
+        if (stableTypeOrdering && array) {
             return array.sort(compareSymbols); // eslint-disable-line local/no-array-mutating-method-expressions
         }
         return array;

src/compiler/commandLineParser.ts

@@ -961,6 +961,15 @@ const commandOptionsWithoutBuild: CommandLineOption[] = [
         description: Diagnostics.Built_in_iterators_are_instantiated_with_a_TReturn_type_of_undefined_instead_of_any,
         defaultValueDescription: Diagnostics.false_unless_strict_is_set,
     },
+    {
+        name: "stableTypeOrdering",
+        type: "boolean",
+        affectsSemanticDiagnostics: true,
+        affectsBuildInfo: true,
+        category: Diagnostics.Type_Checking,
+        description: Diagnostics.Ensure_types_are_ordered_stably_and_deterministically_across_compilations,
+        defaultValueDescription: true,
+    },
     {
         name: "noImplicitThis",
         type: "boolean",

src/compiler/corePublic.ts

@@ -5,11 +5,6 @@ export const versionMajorMinor = "6.0";
 /** The version of the TypeScript compiler release */
 export const version: string = `${versionMajorMinor}.0-dev`;
 
-const tsgoCompatEnv = typeof process !== "undefined" && process.env ? process.env.TSGO_COMPAT : undefined;
-
-/** @internal */
-export const TSGO_COMPAT: boolean = tsgoCompatEnv ? tsgoCompatEnv === "true" : true;
-
 /**
  * Type of objects whose values are all of the same type.
  * The `in` and `for-in` operators can *not* be safely used,

src/compiler/diagnosticMessages.json

@@ -6589,6 +6589,10 @@
         "category": "Message",
         "code": 6808
     },
+    "Ensure types are ordered stably and deterministically across compilations.": {
+        "category": "Message",
+        "code": 6809
+    },
 
     "one of:": {
         "category": "Message",

src/compiler/types.ts

@@ -7541,6 +7541,7 @@ export interface CompilerOptions {
     strictNullChecks?: boolean; // Always combine with strict property
     strictPropertyInitialization?: boolean; // Always combine with strict property
     strictBuiltinIteratorReturn?: boolean; // Always combine with strict property
+    stableTypeOrdering?: boolean;
     stripInternal?: boolean;
     /** @deprecated */
     suppressExcessPropertyErrors?: boolean;

tests/baselines/reference/api/typescript.d.ts

@@ -7114,6 +7114,7 @@ declare namespace ts {
         strictNullChecks?: boolean;
         strictPropertyInitialization?: boolean;
         strictBuiltinIteratorReturn?: boolean;
+        stableTypeOrdering?: boolean;
         stripInternal?: boolean;
         /** @deprecated */
         suppressExcessPropertyErrors?: boolean;

tests/baselines/reference/config/showConfig/Shows tsconfig for single option/stableTypeOrdering/tsconfig.json

@@ -0,0 +1,5 @@
+{
+    "compilerOptions": {
+        "stableTypeOrdering": true
+    }
+}

tests/baselines/reference/tsc/commandLine/help-all.js

@@ -271,6 +271,11 @@ Raise an error when a function parameter isn't read.
 type: boolean
 default: false
 
+--stableTypeOrdering
+Ensure types are ordered stably and deterministically across compilations.
+type: boolean
+default: true
+
 --strict
 Enable all strict type-checking options.
 type: boolean