Add --stableTypeOrdering for TS7 ordering compat

Author: jakebailey

src/compiler/checker.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/commandLineParser.ts

@@ -1209,7 +1209,7 @@ export function binarySearchKey<T, U>(array: readonly T[], key: U, keySelector:
     while (low <= high) {
         const middle = low + ((high - low) >> 1);
         const midKey = keySelector(array[middle], middle);
-        switch (keyComparer(midKey, key)) {
+        switch (Math.sign(keyComparer(midKey, key))) {
             case Comparison.LessThan:
                 low = middle + 1;
                 break;
@@ -1967,9 +1967,11 @@ export function equateStringsCaseSensitive(a: string, b: string): boolean {
     return equateValues(a, b);
 }
 
-function compareComparableValues(a: string | undefined, b: string | undefined): Comparison;
-function compareComparableValues(a: number | undefined, b: number | undefined): Comparison;
-function compareComparableValues(a: string | number | undefined, b: string | number | undefined) {
+/** @internal */
+export function compareComparableValues(a: string | undefined, b: string | undefined): Comparison;
+/** @internal */
+export function compareComparableValues(a: number | undefined, b: number | undefined): Comparison;
+export function compareComparableValues(a: string | number | undefined, b: string | number | undefined) {
     return a === b ? Comparison.EqualTo :
         a === undefined ? Comparison.LessThan :
         b === undefined ? Comparison.GreaterThan :

src/compiler/core.ts

@@ -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/diagnosticMessages.json

@@ -6320,42 +6320,49 @@ export interface SerializedTypeEntry {
     trackedSymbols: readonly TrackedSymbol[] | undefined;
 }
 
+// Note that for types of different kinds, the numeric values of TypeFlags determine the order
+// computed by the CompareTypes function and therefore the order of constituent types in union types.
+// Since union type processing often bails out early when a result is known, it is important to order
+// TypeFlags in increasing order of potential type complexity. In particular, indexed access and
+// conditional types should sort last as those types are potentially recursive and possibly infinite.
+
 // dprint-ignore
 export const enum TypeFlags {
     Any             = 1 << 0,
     Unknown         = 1 << 1,
-    String          = 1 << 2,
-    Number          = 1 << 3,
-    Boolean         = 1 << 4,
-    Enum            = 1 << 5,   // Numeric computed enum member value
-    BigInt          = 1 << 6,
-    StringLiteral   = 1 << 7,
-    NumberLiteral   = 1 << 8,
-    BooleanLiteral  = 1 << 9,
-    EnumLiteral     = 1 << 10,  // Always combined with StringLiteral, NumberLiteral, or Union
-    BigIntLiteral   = 1 << 11,
-    ESSymbol        = 1 << 12,  // Type of symbol primitive introduced in ES6
-    UniqueESSymbol  = 1 << 13,  // unique symbol
-    Void            = 1 << 14,
-    Undefined       = 1 << 15,
-    Null            = 1 << 16,
-    Never           = 1 << 17,  // Never type
-    TypeParameter   = 1 << 18,  // Type parameter
-    Object          = 1 << 19,  // Object type
-    Union           = 1 << 20,  // Union (T | U)
-    Intersection    = 1 << 21,  // Intersection (T & U)
-    Index           = 1 << 22,  // keyof T
-    IndexedAccess   = 1 << 23,  // T[K]
-    Conditional     = 1 << 24,  // T extends U ? X : Y
-    Substitution    = 1 << 25,  // Type parameter substitution
-    NonPrimitive    = 1 << 26,  // intrinsic object type
-    TemplateLiteral = 1 << 27,  // Template literal type
-    StringMapping   = 1 << 28,  // Uppercase/Lowercase type
+    Undefined       = 1 << 2,
+    Null            = 1 << 3,
+    Void            = 1 << 4,
+    String          = 1 << 5,
+    Number          = 1 << 6,
+    BigInt          = 1 << 7,
+    Boolean         = 1 << 8,
+    ESSymbol        = 1 << 9,  // Type of symbol primitive introduced in ES6
+    StringLiteral   = 1 << 10,
+    NumberLiteral   = 1 << 11,
+    BigIntLiteral   = 1 << 12,
+    BooleanLiteral  = 1 << 13,
+    UniqueESSymbol  = 1 << 14,  // unique symbol
+    EnumLiteral     = 1 << 15,  // Always combined with StringLiteral, NumberLiteral, or Union
+    Enum            = 1 << 16,  // Numeric computed enum member value (must be right after EnumLiteral, see getSortOrderFlags)
+    NonPrimitive    = 1 << 17,  // intrinsic object type
+    Never           = 1 << 18,  // Never type
+    TypeParameter   = 1 << 19,  // Type parameter
+    Object          = 1 << 20,  // Object type
+    Index           = 1 << 21,  // keyof T
+    TemplateLiteral = 1 << 22,  // Template literal type
+    StringMapping   = 1 << 23,  // Uppercase/Lowercase type
+    Substitution    = 1 << 24,  // Type parameter substitution
+    IndexedAccess   = 1 << 25,  // T[K]
+    Conditional     = 1 << 26,  // T extends U ? X : Y
+    Union           = 1 << 27,  // Union (T | U)
+    Intersection    = 1 << 28,  // Intersection (T & U)
     /** @internal */
     Reserved1       = 1 << 29,  // Used by union/intersection type construction
     /** @internal */
     Reserved2       = 1 << 30,  // Used by union/intersection type construction
-
+    /** @internal */
+    Reserved3       = 1 << 31,
     /** @internal */
     AnyOrUnknown = Any | Unknown,
     /** @internal */
@@ -6539,14 +6546,16 @@ export const enum ObjectFlags {
     PropagatingFlags = ContainsWideningType | ContainsObjectOrArrayLiteral | NonInferrableType,
     /** @internal */
     InstantiatedMapped = Mapped | Instantiated,
-    // Object flags that uniquely identify the kind of ObjectType
-    /** @internal */
-    ObjectTypeKindMask = ClassOrInterface | Reference | Tuple | Anonymous | Mapped | ReverseMapped | EvolvingArray,
-
+    
     // Flags that require TypeFlags.Object
     ContainsSpread   = 1 << 21,  // Object literal contains spread operation
     ObjectRestType   = 1 << 22,  // Originates in object rest declaration
     InstantiationExpressionType = 1 << 23,  // Originates in instantiation expression
+
+    // Object flags that uniquely identify the kind of ObjectType
+    /** @internal */
+    ObjectTypeKindMask = ClassOrInterface | Reference | Tuple | Anonymous | Mapped | ReverseMapped | EvolvingArray | InstantiationExpressionType | SingleSignatureType,
+
     /** @internal */
     IsClassInstanceClone = 1 << 24, // Type is a clone of a class instance type
     // Flags that require TypeFlags.Object and ObjectFlags.Reference
@@ -7532,6 +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;

src/compiler/types.ts

@@ -6593,53 +6593,53 @@ declare namespace ts {
     enum TypeFlags {
         Any = 1,
         Unknown = 2,
-        String = 4,
-        Number = 8,
-        Boolean = 16,
-        Enum = 32,
-        BigInt = 64,
-        StringLiteral = 128,
-        NumberLiteral = 256,
-        BooleanLiteral = 512,
-        EnumLiteral = 1024,
-        BigIntLiteral = 2048,
-        ESSymbol = 4096,
-        UniqueESSymbol = 8192,
-        Void = 16384,
-        Undefined = 32768,
-        Null = 65536,
-        Never = 131072,
-        TypeParameter = 262144,
-        Object = 524288,
-        Union = 1048576,
-        Intersection = 2097152,
-        Index = 4194304,
-        IndexedAccess = 8388608,
-        Conditional = 16777216,
-        Substitution = 33554432,
-        NonPrimitive = 67108864,
-        TemplateLiteral = 134217728,
-        StringMapping = 268435456,
-        Literal = 2944,
-        Unit = 109472,
-        Freshable = 2976,
-        StringOrNumberLiteral = 384,
-        PossiblyFalsy = 117724,
-        StringLike = 402653316,
-        NumberLike = 296,
-        BigIntLike = 2112,
-        BooleanLike = 528,
-        EnumLike = 1056,
-        ESSymbolLike = 12288,
-        VoidLike = 49152,
-        UnionOrIntersection = 3145728,
-        StructuredType = 3670016,
-        TypeVariable = 8650752,
-        InstantiableNonPrimitive = 58982400,
-        InstantiablePrimitive = 406847488,
-        Instantiable = 465829888,
-        StructuredOrInstantiable = 469499904,
-        Narrowable = 536624127,
+        Undefined = 4,
+        Null = 8,
+        Void = 16,
+        String = 32,
+        Number = 64,
+        BigInt = 128,
+        Boolean = 256,
+        ESSymbol = 512,
+        StringLiteral = 1024,
+        NumberLiteral = 2048,
+        BigIntLiteral = 4096,
+        BooleanLiteral = 8192,
+        UniqueESSymbol = 16384,
+        EnumLiteral = 32768,
+        Enum = 65536,
+        NonPrimitive = 131072,
+        Never = 262144,
+        TypeParameter = 524288,
+        Object = 1048576,
+        Index = 2097152,
+        TemplateLiteral = 4194304,
+        StringMapping = 8388608,
+        Substitution = 16777216,
+        IndexedAccess = 33554432,
+        Conditional = 67108864,
+        Union = 134217728,
+        Intersection = 268435456,
+        Literal = 15360,
+        Unit = 97292,
+        Freshable = 80896,
+        StringOrNumberLiteral = 3072,
+        PossiblyFalsy = 15868,
+        StringLike = 12583968,
+        NumberLike = 67648,
+        BigIntLike = 4224,
+        BooleanLike = 8448,
+        EnumLike = 98304,
+        ESSymbolLike = 16896,
+        VoidLike = 20,
+        UnionOrIntersection = 402653184,
+        StructuredType = 403701760,
+        TypeVariable = 34078720,
+        InstantiableNonPrimitive = 117964800,
+        InstantiablePrimitive = 14680064,
+        Instantiable = 132644864,
+        StructuredOrInstantiable = 536346624,
+        Narrowable = 536575971,
     }
     type DestructuringPattern = BindingPattern | ObjectLiteralExpression | ArrayLiteralExpression;
     interface Type {
@@ -7114,6 +7114,7 @@ declare namespace ts {
         strictNullChecks?: boolean;
         strictPropertyInitialization?: boolean;
         strictBuiltinIteratorReturn?: boolean;
+        stableTypeOrdering?: boolean;
         stripInternal?: boolean;
         /** @deprecated */
         suppressExcessPropertyErrors?: boolean;

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

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

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

@@ -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