Revert fix for intersections in template literals, fix differently (#52836)

src/compiler/checker.ts

@@ -17070,32 +17070,24 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         }
         return type;
 
-        function addSpans(texts: readonly string[] | string, types: readonly Type[]): boolean {
-            const isTextsArray = isArray(texts);
+        function addSpans(texts: readonly string[], types: readonly Type[]): boolean {
             for (let i = 0; i < types.length; i++) {
                 const t = types[i];
-                const addText = isTextsArray ? texts[i + 1] : texts;
                 if (t.flags & (TypeFlags.Literal | TypeFlags.Null | TypeFlags.Undefined)) {
                     text += getTemplateStringForType(t) || "";
-                    text += addText;
-                    if (!isTextsArray) return true;
+                    text += texts[i + 1];
                 }
                 else if (t.flags & TypeFlags.TemplateLiteral) {
                     text += (t as TemplateLiteralType).texts[0];
                     if (!addSpans((t as TemplateLiteralType).texts, (t as TemplateLiteralType).types)) return false;
-                    text += addText;
-                    if (!isTextsArray) return true;
+                    text += texts[i + 1];
                 }
                 else if (isGenericIndexType(t) || isPatternLiteralPlaceholderType(t)) {
                     newTypes.push(t);
                     newTexts.push(text);
-                    text = addText;
+                    text = texts[i + 1];
                 }
-                else if (t.flags & TypeFlags.Intersection) {
-                    const added = addSpans(texts[i + 1], (t as IntersectionType).types);
-                    if (!added) return false;
-                }
-                else if (isTextsArray) {
+                else {
                     return false;
                 }
             }
@@ -17113,6 +17105,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
 
     function createTemplateLiteralType(texts: readonly string[], types: readonly Type[]) {
         const type = createType(TypeFlags.TemplateLiteral) as TemplateLiteralType;
+        type.objectFlags = getPropagatingFlagsOfTypes(types, /*excludeKinds*/ TypeFlags.Nullable);
         type.texts = texts;
         type.types = types;
         return type;
@@ -17120,6 +17113,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
 
     function getStringMappingType(symbol: Symbol, type: Type): Type {
         return type.flags & (TypeFlags.Union | TypeFlags.Never) ? mapType(type, t => getStringMappingType(symbol, t)) :
+            type.flags & TypeFlags.Intersection ? getIntersectionType(map((type as IntersectionType).types, t => getStringMappingType(symbol, t))) :
             type.flags & TypeFlags.StringLiteral ? getStringLiteralType(applyStringMapping(symbol, (type as StringLiteralType).value)) :
             type.flags & TypeFlags.TemplateLiteral ? getTemplateLiteralType(...applyTemplateStringMapping(symbol, (type as TemplateLiteralType).texts, (type as TemplateLiteralType).types)) :
             // Mapping<Mapping<T>> === Mapping<T>
@@ -17423,6 +17417,9 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function isPatternLiteralPlaceholderType(type: Type): boolean {
+        if (type.flags & TypeFlags.Intersection) {
+            return some((type as IntersectionType).types, t => !!(t.flags & (TypeFlags.Literal | TypeFlags.Null | TypeFlags.Undefined)) || isPatternLiteralPlaceholderType(t));
+        }
         return !!(type.flags & (TypeFlags.Any | TypeFlags.String | TypeFlags.Number | TypeFlags.BigInt)) || isPatternLiteralType(type);
     }
 
@@ -17444,12 +17441,12 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     }
 
     function getGenericObjectFlags(type: Type): ObjectFlags {
-        if (type.flags & TypeFlags.UnionOrIntersection) {
-            if (!((type as UnionOrIntersectionType).objectFlags & ObjectFlags.IsGenericTypeComputed)) {
-                (type as UnionOrIntersectionType).objectFlags |= ObjectFlags.IsGenericTypeComputed |
-                    reduceLeft((type as UnionOrIntersectionType).types, (flags, t) => flags | getGenericObjectFlags(t), 0);
+        if (type.flags & (TypeFlags.UnionOrIntersection | TypeFlags.TemplateLiteral)) {
+            if (!((type as UnionOrIntersectionType | TemplateLiteralType).objectFlags & ObjectFlags.IsGenericTypeComputed)) {
+                (type as UnionOrIntersectionType | TemplateLiteralType).objectFlags |= ObjectFlags.IsGenericTypeComputed |
+                    reduceLeft((type as UnionOrIntersectionType | TemplateLiteralType).types, (flags, t) => flags | getGenericObjectFlags(t), 0);
             }
-            return (type as UnionOrIntersectionType).objectFlags & ObjectFlags.IsGenericType;
+            return (type as UnionOrIntersectionType | TemplateLiteralType).objectFlags & ObjectFlags.IsGenericType;
         }
         if (type.flags & TypeFlags.Substitution) {
             if (!((type as SubstitutionType).objectFlags & ObjectFlags.IsGenericTypeComputed)) {
@@ -17459,7 +17456,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             return (type as SubstitutionType).objectFlags & ObjectFlags.IsGenericType;
         }
         return (type.flags & TypeFlags.InstantiableNonPrimitive || isGenericMappedType(type) || isGenericTupleType(type) ? ObjectFlags.IsGenericObjectType : 0) |
-            (type.flags & (TypeFlags.InstantiableNonPrimitive | TypeFlags.Index | TypeFlags.TemplateLiteral | TypeFlags.StringMapping) && !isPatternLiteralType(type) ? ObjectFlags.IsGenericIndexType : 0);
+            (type.flags & (TypeFlags.InstantiableNonPrimitive | TypeFlags.Index | TypeFlags.StringMapping) && !isPatternLiteralType(type) ? ObjectFlags.IsGenericIndexType : 0);
     }
 
     function getSimplifiedType(type: Type, writing: boolean): Type {
@@ -23896,7 +23893,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 objectFlags & ObjectFlags.Reference && ((type as TypeReference).node || some(getTypeArguments(type as TypeReference), couldContainTypeVariables)) ||
                 objectFlags & ObjectFlags.Anonymous && type.symbol && type.symbol.flags & (SymbolFlags.Function | SymbolFlags.Method | SymbolFlags.Class | SymbolFlags.TypeLiteral | SymbolFlags.ObjectLiteral) && type.symbol.declarations ||
                 objectFlags & (ObjectFlags.Mapped | ObjectFlags.ReverseMapped | ObjectFlags.ObjectRestType | ObjectFlags.InstantiationExpressionType)) ||
-            type.flags & TypeFlags.UnionOrIntersection && !(type.flags & TypeFlags.EnumLiteral) && !isNonGenericTopLevelType(type) && some((type as UnionOrIntersectionType).types, couldContainTypeVariables));
+            type.flags & (TypeFlags.UnionOrIntersection | TypeFlags.TemplateLiteral) && !(type.flags & TypeFlags.EnumLiteral) && !isNonGenericTopLevelType(type) && some((type as UnionOrIntersectionType | TemplateLiteralType).types, couldContainTypeVariables));
         if (type.flags & TypeFlags.ObjectFlagsType) {
             (type as ObjectFlagsType).objectFlags |= ObjectFlags.CouldContainTypeVariablesComputed | (result ? ObjectFlags.CouldContainTypeVariables : 0);
         }

src/compiler/types.ts

@@ -6107,7 +6107,7 @@ export const enum TypeFlags {
     Instantiable = InstantiableNonPrimitive | InstantiablePrimitive,
     StructuredOrInstantiable = StructuredType | Instantiable,
     /** @internal */
-    ObjectFlagsType = Any | Nullable | Never | Object | Union | Intersection,
+    ObjectFlagsType = Any | Nullable | Never | Object | Union | Intersection | TemplateLiteral,
     /** @internal */
     Simplifiable = IndexedAccess | Conditional,
     /** @internal */
@@ -6261,7 +6261,7 @@ export const enum ObjectFlags {
     /** @internal */
     IdenticalBaseTypeExists = 1 << 26, // has a defined cachedEquivalentBaseType member
 
-    // Flags that require TypeFlags.UnionOrIntersection or TypeFlags.Substitution
+    // Flags that require TypeFlags.UnionOrIntersection, TypeFlags.Substitution, or TypeFlags.TemplateLiteral
     /** @internal */
     IsGenericTypeComputed = 1 << 21, // IsGenericObjectType flag has been computed
     /** @internal */
@@ -6288,7 +6288,7 @@ export const enum ObjectFlags {
 }
 
 /** @internal */
-export type ObjectFlagsType = NullableType | ObjectType | UnionType | IntersectionType;
+export type ObjectFlagsType = NullableType | ObjectType | UnionType | IntersectionType | TemplateLiteralType;
 
 // Object types (TypeFlags.ObjectType)
 export interface ObjectType extends Type {
@@ -6636,6 +6636,8 @@ export interface ConditionalType extends InstantiableType {
 }
 
 export interface TemplateLiteralType extends InstantiableType {
+    /** @internal */
+    objectFlags: ObjectFlags;
     texts: readonly string[];  // Always one element longer than types
     types: readonly Type[];  // Always at least one element
 }

tests/baselines/reference/deeplyNestedTemplateLiteralIntersection.errors.txt

@@ -0,0 +1,29 @@
+tests/cases/compiler/deeplyNestedTemplateLiteralIntersection.ts(20,11): error TS2590: Expression produces a union type that is too complex to represent.
+
+
+==== tests/cases/compiler/deeplyNestedTemplateLiteralIntersection.ts (1 errors) ====
+    type R = `${number}a` & {
+        _thing: true;
+    };
+    
+    type _S = "1" | "2" | "3" | "4" | "5" | "6";
+    
+    type S = `${_S}${_S}${_S}`;
+    
+    
+    type T = R | S;
+    type X = `${T} ${T}`;
+    
+    export type Props = Partial<{
+        x: X;
+    }>;
+    
+    const a1: Props = {};
+    const a2: Props = {};
+    
+    const b = { ...a1, ...a2 };
+              ~~~~~~~~~~~~~~~~
+!!! error TS2590: Expression produces a union type that is too complex to represent.
+    
+    export { b };
+    

tests/baselines/reference/templateLiteralIntersection.types

@@ -16,7 +16,7 @@ type OriginA1 = `${A}`
 >OriginA1 : "a"
 
 type OriginA2 = `${MixA}`
->OriginA2 : "a"
+>OriginA2 : `${MixA}`
 
 type B = `${typeof a}`
 >B : "a"
@@ -30,14 +30,14 @@ type OriginB1 = `${B}`
 >OriginB1 : "a"
 
 type OriginB2 = `${MixB}`
->OriginB2 : "a"
+>OriginB2 : `${MixB}`
 
 type MixC = { foo: string } & A
 >MixC : { foo: string; } & "a"
 >foo : string
 
 type OriginC = `${MixC}`
->OriginC : "a"
+>OriginC : `${MixC}`
 
 type MixD<T extends string> =
 >MixD : `${T & { foo: string; }}`
@@ -46,7 +46,7 @@ type MixD<T extends string> =
 >foo : string
 
 type OriginD = `${MixD<A & { foo: string }> & { foo: string }}`;
->OriginD : "a"
+>OriginD : `${`${"a" & { foo: string; } & { foo: string; }}` & { foo: string; }}`
 >foo : string
 >foo : string
 

tests/baselines/reference/templateLiteralIntersection2.errors.txt

@@ -0,0 +1,41 @@
+tests/cases/compiler/templateLiteralIntersection2.ts(7,12): error TS2345: Argument of type '"foo/bar"' is not assignable to parameter of type '`${Path}/${Path}`'.
+tests/cases/compiler/templateLiteralIntersection2.ts(20,10): error TS2345: Argument of type '""' is not assignable to parameter of type '`a${string}` & `${string}a`'.
+  Type '""' is not assignable to type '`a${string}`'.
+tests/cases/compiler/templateLiteralIntersection2.ts(22,10): error TS2345: Argument of type '"ab"' is not assignable to parameter of type '`a${string}` & `${string}a`'.
+  Type '"ab"' is not assignable to type '`${string}a`'.
+
+
+==== tests/cases/compiler/templateLiteralIntersection2.ts (3 errors) ====
+    type Path = string & { _pathBrand: any };
+    
+    type JoinedPath = `${Path}/${Path}`;
+    
+    declare function joinedPath(p: JoinedPath): void;
+    
+    joinedPath("foo/bar");
+               ~~~~~~~~~
+!!! error TS2345: Argument of type '"foo/bar"' is not assignable to parameter of type '`${Path}/${Path}`'.
+    
+    declare const somePath: Path;
+    
+    joinedPath(`${somePath}/${somePath}`);
+    
+    
+    type StartsWithA = `a${string}`;
+    type EndsWithA = `${string}a`;
+    
+    
+    declare function withinAs(p: StartsWithA & EndsWithA): void;
+    
+    withinAs("");
+             ~~
+!!! error TS2345: Argument of type '""' is not assignable to parameter of type '`a${string}` & `${string}a`'.
+!!! error TS2345:   Type '""' is not assignable to type '`a${string}`'.
+    withinAs("a");
+    withinAs("ab");
+             ~~~~
+!!! error TS2345: Argument of type '"ab"' is not assignable to parameter of type '`a${string}` & `${string}a`'.
+!!! error TS2345:   Type '"ab"' is not assignable to type '`${string}a`'.
+    withinAs("aba");
+    withinAs("abavvvva");
+    

tests/baselines/reference/templateLiteralIntersection2.symbols

@@ -0,0 +1,56 @@
+=== tests/cases/compiler/templateLiteralIntersection2.ts ===
+type Path = string & { _pathBrand: any };
+>Path : Symbol(Path, Decl(templateLiteralIntersection2.ts, 0, 0))
+>_pathBrand : Symbol(_pathBrand, Decl(templateLiteralIntersection2.ts, 0, 22))
+
+type JoinedPath = `${Path}/${Path}`;
+>JoinedPath : Symbol(JoinedPath, Decl(templateLiteralIntersection2.ts, 0, 41))
+>Path : Symbol(Path, Decl(templateLiteralIntersection2.ts, 0, 0))
+>Path : Symbol(Path, Decl(templateLiteralIntersection2.ts, 0, 0))
+
+declare function joinedPath(p: JoinedPath): void;
+>joinedPath : Symbol(joinedPath, Decl(templateLiteralIntersection2.ts, 2, 36))
+>p : Symbol(p, Decl(templateLiteralIntersection2.ts, 4, 28))
+>JoinedPath : Symbol(JoinedPath, Decl(templateLiteralIntersection2.ts, 0, 41))
+
+joinedPath("foo/bar");
+>joinedPath : Symbol(joinedPath, Decl(templateLiteralIntersection2.ts, 2, 36))
+
+declare const somePath: Path;
+>somePath : Symbol(somePath, Decl(templateLiteralIntersection2.ts, 8, 13))
+>Path : Symbol(Path, Decl(templateLiteralIntersection2.ts, 0, 0))
+
+joinedPath(`${somePath}/${somePath}`);
+>joinedPath : Symbol(joinedPath, Decl(templateLiteralIntersection2.ts, 2, 36))
+>somePath : Symbol(somePath, Decl(templateLiteralIntersection2.ts, 8, 13))
+>somePath : Symbol(somePath, Decl(templateLiteralIntersection2.ts, 8, 13))
+
+
+type StartsWithA = `a${string}`;
+>StartsWithA : Symbol(StartsWithA, Decl(templateLiteralIntersection2.ts, 10, 38))
+
+type EndsWithA = `${string}a`;
+>EndsWithA : Symbol(EndsWithA, Decl(templateLiteralIntersection2.ts, 13, 32))
+
+
+declare function withinAs(p: StartsWithA & EndsWithA): void;
+>withinAs : Symbol(withinAs, Decl(templateLiteralIntersection2.ts, 14, 30))
+>p : Symbol(p, Decl(templateLiteralIntersection2.ts, 17, 26))
+>StartsWithA : Symbol(StartsWithA, Decl(templateLiteralIntersection2.ts, 10, 38))
+>EndsWithA : Symbol(EndsWithA, Decl(templateLiteralIntersection2.ts, 13, 32))
+
+withinAs("");
+>withinAs : Symbol(withinAs, Decl(templateLiteralIntersection2.ts, 14, 30))
+
+withinAs("a");
+>withinAs : Symbol(withinAs, Decl(templateLiteralIntersection2.ts, 14, 30))
+
+withinAs("ab");
+>withinAs : Symbol(withinAs, Decl(templateLiteralIntersection2.ts, 14, 30))
+
+withinAs("aba");
+>withinAs : Symbol(withinAs, Decl(templateLiteralIntersection2.ts, 14, 30))
+
+withinAs("abavvvva");
+>withinAs : Symbol(withinAs, Decl(templateLiteralIntersection2.ts, 14, 30))
+

tests/baselines/reference/templateLiteralIntersection2.types

@@ -0,0 +1,64 @@
+=== tests/cases/compiler/templateLiteralIntersection2.ts ===
+type Path = string & { _pathBrand: any };
+>Path : string & { _pathBrand: any; }
+>_pathBrand : any
+
+type JoinedPath = `${Path}/${Path}`;
+>JoinedPath : `${Path}/${Path}`
+
+declare function joinedPath(p: JoinedPath): void;
+>joinedPath : (p: JoinedPath) => void
+>p : `${Path}/${Path}`
+
+joinedPath("foo/bar");
+>joinedPath("foo/bar") : void
+>joinedPath : (p: `${Path}/${Path}`) => void
+>"foo/bar" : "foo/bar"
+
+declare const somePath: Path;
+>somePath : Path
+
+joinedPath(`${somePath}/${somePath}`);
+>joinedPath(`${somePath}/${somePath}`) : void
+>joinedPath : (p: `${Path}/${Path}`) => void
+>`${somePath}/${somePath}` : `${Path}/${Path}`
+>somePath : Path
+>somePath : Path
+
+
+type StartsWithA = `a${string}`;
+>StartsWithA : `a${string}`
+
+type EndsWithA = `${string}a`;
+>EndsWithA : `${string}a`
+
+
+declare function withinAs(p: StartsWithA & EndsWithA): void;
+>withinAs : (p: StartsWithA & EndsWithA) => void
+>p : `a${string}` & `${string}a`
+
+withinAs("");
+>withinAs("") : void
+>withinAs : (p: `a${string}` & `${string}a`) => void
+>"" : ""
+
+withinAs("a");
+>withinAs("a") : void
+>withinAs : (p: `a${string}` & `${string}a`) => void
+>"a" : "a"
+
+withinAs("ab");
+>withinAs("ab") : void
+>withinAs : (p: `a${string}` & `${string}a`) => void
+>"ab" : "ab"
+
+withinAs("aba");
+>withinAs("aba") : void
+>withinAs : (p: `a${string}` & `${string}a`) => void
+>"aba" : "aba"
+
+withinAs("abavvvva");
+>withinAs("abavvvva") : void
+>withinAs : (p: `a${string}` & `${string}a`) => void
+>"abavvvva" : "abavvvva"
+

tests/baselines/reference/templateLiteralIntersection3.symbols

@@ -0,0 +1,32 @@
+=== tests/cases/compiler/templateLiteralIntersection3.ts ===
+type Path = string & { _pathBrand: any };
+>Path : Symbol(Path, Decl(templateLiteralIntersection3.ts, 0, 0))
+>_pathBrand : Symbol(_pathBrand, Decl(templateLiteralIntersection3.ts, 0, 22))
+
+declare const path: Path;
+>path : Symbol(path, Decl(templateLiteralIntersection3.ts, 1, 13))
+>Path : Symbol(Path, Decl(templateLiteralIntersection3.ts, 0, 0))
+
+declare const options1: { prop: number; } & { [k: string]: boolean; };
+>options1 : Symbol(options1, Decl(templateLiteralIntersection3.ts, 3, 13))
+>prop : Symbol(prop, Decl(templateLiteralIntersection3.ts, 3, 25))
+>k : Symbol(k, Decl(templateLiteralIntersection3.ts, 3, 47))
+
+options1[`foo`] = false;
+>options1 : Symbol(options1, Decl(templateLiteralIntersection3.ts, 3, 13))
+
+options1[`foo/${path}`] = false;
+>options1 : Symbol(options1, Decl(templateLiteralIntersection3.ts, 3, 13))
+>path : Symbol(path, Decl(templateLiteralIntersection3.ts, 1, 13))
+
+
+// Lowercase<`foo/${Path}`> => `foo/${Lowercase<Path>}`
+declare const lowercasePath: Lowercase<`foo/${Path}`>;
+>lowercasePath : Symbol(lowercasePath, Decl(templateLiteralIntersection3.ts, 11, 13))
+>Lowercase : Symbol(Lowercase, Decl(lib.es5.d.ts, --, --))
+>Path : Symbol(Path, Decl(templateLiteralIntersection3.ts, 0, 0))
+
+options1[lowercasePath] = false;
+>options1 : Symbol(options1, Decl(templateLiteralIntersection3.ts, 3, 13))
+>lowercasePath : Symbol(lowercasePath, Decl(templateLiteralIntersection3.ts, 11, 13))
+

tests/baselines/reference/templateLiteralIntersection3.types

@@ -0,0 +1,40 @@
+=== tests/cases/compiler/templateLiteralIntersection3.ts ===
+type Path = string & { _pathBrand: any };
+>Path : string & { _pathBrand: any; }
+>_pathBrand : any
+
+declare const path: Path;
+>path : Path
+
+declare const options1: { prop: number; } & { [k: string]: boolean; };
+>options1 : { prop: number; } & { [k: string]: boolean; }
+>prop : number
+>k : string
+
+options1[`foo`] = false;
+>options1[`foo`] = false : false
+>options1[`foo`] : boolean
+>options1 : { prop: number; } & { [k: string]: boolean; }
+>`foo` : "foo"
+>false : false
+
+options1[`foo/${path}`] = false;
+>options1[`foo/${path}`] = false : false
+>options1[`foo/${path}`] : boolean
+>options1 : { prop: number; } & { [k: string]: boolean; }
+>`foo/${path}` : `foo/${Path}`
+>path : Path
+>false : false
+
+
+// Lowercase<`foo/${Path}`> => `foo/${Lowercase<Path>}`
+declare const lowercasePath: Lowercase<`foo/${Path}`>;
+>lowercasePath : `foo/${Lowercase<string> & { _pathBrand: any; }}`
+
+options1[lowercasePath] = false;
+>options1[lowercasePath] = false : false
+>options1[lowercasePath] : boolean
+>options1 : { prop: number; } & { [k: string]: boolean; }
+>lowercasePath : `foo/${Lowercase<string> & { _pathBrand: any; }}`
+>false : false
+

tests/cases/compiler/deeplyNestedTemplateLiteralIntersection.ts

@@ -0,0 +1,27 @@
+// @strict: true
+// @noEmit: true
+// @noTypesAndSymbols: true
+
+
+type R = `${number}a` & {
+    _thing: true;
+};
+
+type _S = "1" | "2" | "3" | "4" | "5" | "6";
+
+type S = `${_S}${_S}${_S}`;
+
+
+type T = R | S;
+type X = `${T} ${T}`;
+
+export type Props = Partial<{
+    x: X;
+}>;
+
+const a1: Props = {};
+const a2: Props = {};
+
+const b = { ...a1, ...a2 };
+
+export { b };

tests/cases/compiler/templateLiteralIntersection2.ts

@@ -0,0 +1,27 @@
+// @strict: true
+// @noEmit: true
+
+type Path = string & { _pathBrand: any };
+
+type JoinedPath = `${Path}/${Path}`;
+
+declare function joinedPath(p: JoinedPath): void;
+
+joinedPath("foo/bar");
+
+declare const somePath: Path;
+
+joinedPath(`${somePath}/${somePath}`);
+
+
+type StartsWithA = `a${string}`;
+type EndsWithA = `${string}a`;
+
+
+declare function withinAs(p: StartsWithA & EndsWithA): void;
+
+withinAs("");
+withinAs("a");
+withinAs("ab");
+withinAs("aba");
+withinAs("abavvvva");

tests/cases/compiler/templateLiteralIntersection3.ts

@@ -0,0 +1,17 @@
+// @strict: true
+// @noEmit: true
+
+type Path = string & { _pathBrand: any };
+declare const path: Path;
+
+declare const options1: { prop: number; } & { [k: string]: boolean; };
+
+options1[`foo`] = false;
+
+options1[`foo/${path}`] = false;
+
+
+// Lowercase<`foo/${Path}`> => `foo/${Lowercase<Path>}`
+declare const lowercasePath: Lowercase<`foo/${Path}`>;
+
+options1[lowercasePath] = false;