Use evaluator for isolatedModules enum restrictions

src/compiler/emitter.ts

@@ -1102,6 +1102,7 @@ export const notImplementedResolver: EmitResolver = {
     isEntityNameVisible: notImplemented,
     // Returns the constant value this property access resolves to: notImplemented, or 'undefined' for a non-constant
     getConstantValue: notImplemented,
+    getEnumMemberValue: notImplemented,
     getReferencedValueDeclaration: notImplemented,
     getReferencedValueDeclarations: notImplemented,
     getTypeReferenceSerializationKind: notImplemented,

src/compiler/transformers/ts.ts

@@ -122,7 +122,6 @@ import {
     isSimpleInlineableExpression,
     isSourceFile,
     isStatement,
-    isSyntacticallyString,
     isTemplateLiteral,
     isTryStatement,
     JsxOpeningElement,
@@ -1915,15 +1914,16 @@ export function transformTypeScript(context: TransformationContext) {
         // we pass false as 'generateNameForComputedPropertyName' for a backward compatibility purposes
         // old emitter always generate 'expression' part of the name as-is.
         const name = getExpressionForPropertyName(member, /*generateNameForComputedPropertyName*/ false);
-        const valueExpression = transformEnumMemberDeclarationValue(member);
+        const evaluated = resolver.getEnumMemberValue(member);
+        const valueExpression = transformEnumMemberDeclarationValue(member, evaluated?.value);
         const innerAssignment = factory.createAssignment(
             factory.createElementAccessExpression(
                 currentNamespaceContainerName,
                 name,
             ),
             valueExpression,
         );
-        const outerAssignment = isSyntacticallyString(valueExpression) ?
+        const outerAssignment = evaluated?.isSyntacticallyString ?
             innerAssignment :
             factory.createAssignment(
                 factory.createElementAccessExpression(
@@ -1948,12 +1948,11 @@ export function transformTypeScript(context: TransformationContext) {
      *
      * @param member The enum member node.
      */
-    function transformEnumMemberDeclarationValue(member: EnumMember): Expression {
-        const value = resolver.getConstantValue(member);
-        if (value !== undefined) {
-            return typeof value === "string" ? factory.createStringLiteral(value) :
-                value < 0 ? factory.createPrefixUnaryExpression(SyntaxKind.MinusToken, factory.createNumericLiteral(-value)) :
-                factory.createNumericLiteral(value);
+    function transformEnumMemberDeclarationValue(member: EnumMember, constantValue: string | number | undefined): Expression {
+        if (constantValue !== undefined) {
+            return typeof constantValue === "string" ? factory.createStringLiteral(constantValue) :
+                constantValue < 0 ? factory.createPrefixUnaryExpression(SyntaxKind.MinusToken, factory.createNumericLiteral(-constantValue)) :
+                factory.createNumericLiteral(constantValue);
         }
         else {
             enableSubstitutionForNonQualifiedEnumMembers();

src/compiler/types.ts

@@ -5607,6 +5607,7 @@ export interface EmitResolver {
     isEntityNameVisible(entityName: EntityNameOrEntityNameExpression, enclosingDeclaration: Node): SymbolVisibilityResult;
     // Returns the constant value this property access resolves to, or 'undefined' for a non-constant
     getConstantValue(node: EnumMember | PropertyAccessExpression | ElementAccessExpression): string | number | undefined;
+    getEnumMemberValue(node: EnumMember): EvaluatorResult | undefined;
     getReferencedValueDeclaration(reference: Identifier): Declaration | undefined;
     getReferencedValueDeclarations(reference: Identifier): Declaration[] | undefined;
     getTypeReferenceSerializationKind(typeName: EntityName, location?: Node): TypeReferenceSerializationKind;
@@ -5939,6 +5940,13 @@ export const enum NodeCheckFlags {
     InCheckIdentifier                        = 1 << 22,
 }
 
+/** @internal */
+export interface EvaluatorResult<T extends string | number | undefined = string | number | undefined> {
+    value: T;
+    isSyntacticallyString: boolean;
+    resolvedOtherFiles: boolean;
+}
+
 // dprint-ignore
 /** @internal */
 export interface NodeLinks {
@@ -5949,7 +5957,7 @@ export interface NodeLinks {
     resolvedSymbol?: Symbol;            // Cached name resolution result
     resolvedIndexInfo?: IndexInfo;      // Cached indexing info resolution result
     effectsSignature?: Signature;       // Signature with possible control flow effects
-    enumMemberValue?: string | number;  // Constant value of enum member
+    enumMemberValue?: EvaluatorResult;  // Constant value of enum member
     isVisible?: boolean;                // Is this node visible
     containsArgumentsReference?: boolean; // Whether a function-like declaration contains an 'arguments' reference
     hasReportedStatementInAmbientContext?: boolean; // Cache boolean if we report statements in ambient context

src/compiler/utilities.ts

@@ -10641,22 +10641,3 @@ export function replaceFirstStar(s: string, replacement: string): string {
 export function getNameFromImportAttribute(node: ImportAttribute) {
     return isIdentifier(node.name) ? node.name.escapedText : escapeLeadingUnderscores(node.name.text);
 }
-
-/** @internal */
-export function isSyntacticallyString(expr: Expression): boolean {
-    expr = skipOuterExpressions(expr);
-    switch (expr.kind) {
-        case SyntaxKind.BinaryExpression:
-            const left = (expr as BinaryExpression).left;
-            const right = (expr as BinaryExpression).right;
-            return (
-                (expr as BinaryExpression).operatorToken.kind === SyntaxKind.PlusToken &&
-                (isSyntacticallyString(left) || isSyntacticallyString(right))
-            );
-        case SyntaxKind.TemplateExpression:
-        case SyntaxKind.StringLiteral:
-        case SyntaxKind.NoSubstitutionTemplateLiteral:
-            return true;
-    }
-    return false;
-}

tests/baselines/reference/computedEnumMemberSyntacticallyString(isolatedmodules=false).errors.txt

@@ -3,9 +3,12 @@ computedEnumMemberSyntacticallyString.ts(5,9): error TS18033: Type 'string' is n
 computedEnumMemberSyntacticallyString.ts(6,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
 computedEnumMemberSyntacticallyString.ts(7,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
 computedEnumMemberSyntacticallyString.ts(8,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+computedEnumMemberSyntacticallyString.ts(10,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+computedEnumMemberSyntacticallyString.ts(11,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+computedEnumMemberSyntacticallyString.ts(14,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
 
 
-==== computedEnumMemberSyntacticallyString.ts (5 errors) ====
+==== computedEnumMemberSyntacticallyString.ts (8 errors) ====
     const BAR = 2..toFixed(0);
 
     enum Foo {
@@ -24,5 +27,18 @@ computedEnumMemberSyntacticallyString.ts(8,9): error TS18033: Type 'string' is n
         E = `${BAR}`!,
             ~~~~~~~~~
 !!! error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+
+        F = BAR,
+            ~~~
+!!! error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+        G = 2 + BAR,
+            ~~~~~~~
+!!! error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+
+        H = A,
+        I = H + BAR,
+            ~~~~~~~
+!!! error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+        J = H
     }
 

tests/baselines/reference/computedEnumMemberSyntacticallyString(isolatedmodules=false).js

@@ -9,6 +9,13 @@ enum Foo {
     C = (`${BAR}`),
     D = (`${BAR}}`) as string,
     E = `${BAR}`!,
+
+    F = BAR,
+    G = 2 + BAR,
+
+    H = A,
+    I = H + BAR,
+    J = H
 }
 
 
@@ -21,4 +28,9 @@ var Foo;
     Foo["C"] = (`${BAR}`);
     Foo["D"] = (`${BAR}}`);
     Foo["E"] = `${BAR}`;
+    Foo[Foo["F"] = BAR] = "F";
+    Foo[Foo["G"] = 2 + BAR] = "G";
+    Foo["H"] = Foo.A;
+    Foo["I"] = Foo.H + BAR;
+    Foo["J"] = Foo.H;
 })(Foo || (Foo = {}));

tests/baselines/reference/computedEnumMemberSyntacticallyString(isolatedmodules=true).errors.txt

@@ -3,9 +3,12 @@ computedEnumMemberSyntacticallyString.ts(5,9): error TS18033: Type 'string' is n
 computedEnumMemberSyntacticallyString.ts(6,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
 computedEnumMemberSyntacticallyString.ts(7,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
 computedEnumMemberSyntacticallyString.ts(8,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+computedEnumMemberSyntacticallyString.ts(10,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+computedEnumMemberSyntacticallyString.ts(11,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+computedEnumMemberSyntacticallyString.ts(14,9): error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
 
 
-==== computedEnumMemberSyntacticallyString.ts (5 errors) ====
+==== computedEnumMemberSyntacticallyString.ts (8 errors) ====
     const BAR = 2..toFixed(0);
 
     enum Foo {
@@ -24,5 +27,18 @@ computedEnumMemberSyntacticallyString.ts(8,9): error TS18033: Type 'string' is n
         E = `${BAR}`!,
             ~~~~~~~~~
 !!! error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+
+        F = BAR,
+            ~~~
+!!! error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+        G = 2 + BAR,
+            ~~~~~~~
+!!! error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+
+        H = A,
+        I = H + BAR,
+            ~~~~~~~
+!!! error TS18033: Type 'string' is not assignable to type 'number' as required for computed enum member values.
+        J = H
     }
 

tests/baselines/reference/computedEnumMemberSyntacticallyString(isolatedmodules=true).js

@@ -9,6 +9,13 @@ enum Foo {
     C = (`${BAR}`),
     D = (`${BAR}}`) as string,
     E = `${BAR}`!,
+
+    F = BAR,
+    G = 2 + BAR,
+
+    H = A,
+    I = H + BAR,
+    J = H
 }
 
 
@@ -21,4 +28,9 @@ var Foo;
     Foo["C"] = (`${BAR}`);
     Foo["D"] = (`${BAR}}`);
     Foo["E"] = `${BAR}`;
+    Foo[Foo["F"] = BAR] = "F";
+    Foo[Foo["G"] = 2 + BAR] = "G";
+    Foo["H"] = Foo.A;
+    Foo["I"] = Foo.H + BAR;
+    Foo["J"] = Foo.H;
 })(Foo || (Foo = {}));

tests/baselines/reference/computedEnumMemberSyntacticallyString2(isolatedmodules=false).js

@@ -2,7 +2,22 @@
 
 //// [foo.ts]
 import { BAR } from './bar';
-enum Foo { A = `${BAR}` }
+const LOCAL = 'LOCAL';
+
+enum Foo {
+  A = `${BAR}`,
+
+  B = LOCAL,
+  C = B,
+  D = C + 'BAR',
+
+  F = BAR,
+  G = 2 + BAR,
+
+  H = A,
+  I = H + BAR,
+  J = H
+}
 
 //// [bar.ts]
 export const BAR = 'bar';
@@ -11,7 +26,16 @@ export const BAR = 'bar';
 export const BAR = 'bar';
 //// [foo.js]
 import { BAR } from './bar';
+const LOCAL = 'LOCAL';
 var Foo;
 (function (Foo) {
     Foo["A"] = "bar";
+    Foo["B"] = "LOCAL";
+    Foo["C"] = "LOCAL";
+    Foo["D"] = "LOCALBAR";
+    Foo[Foo["F"] = "bar"] = "F";
+    Foo[Foo["G"] = "2bar"] = "G";
+    Foo["H"] = "bar";
+    Foo["I"] = "barbar";
+    Foo["J"] = "bar";
 })(Foo || (Foo = {}));

tests/baselines/reference/computedEnumMemberSyntacticallyString2(isolatedmodules=true).errors.txt

@@ -0,0 +1,29 @@
+foo.ts(11,7): error TS18055: 'Foo.F' has a string type, but must have syntactically recognizable string syntax when 'isolatedModules' is enabled.
+foo.ts(12,7): error TS18055: 'Foo.G' has a string type, but must have syntactically recognizable string syntax when 'isolatedModules' is enabled.
+
+
+==== ./foo.ts (2 errors) ====
+    import { BAR } from './bar';
+    const LOCAL = 'LOCAL';
+
+    enum Foo {
+      A = `${BAR}`,
+
+      B = LOCAL,
+      C = B,
+      D = C + 'BAR',
+
+      F = BAR,
+          ~~~
+!!! error TS18055: 'Foo.F' has a string type, but must have syntactically recognizable string syntax when 'isolatedModules' is enabled.
+      G = 2 + BAR,
+          ~~~~~~~
+!!! error TS18055: 'Foo.G' has a string type, but must have syntactically recognizable string syntax when 'isolatedModules' is enabled.
+
+      H = A,
+      I = H + BAR,
+      J = H
+    }
+
+==== ./bar.ts (0 errors) ====
+    export const BAR = 'bar';

tests/baselines/reference/computedEnumMemberSyntacticallyString2(isolatedmodules=true).js

@@ -2,7 +2,22 @@
 
 //// [foo.ts]
 import { BAR } from './bar';
-enum Foo { A = `${BAR}` }
+const LOCAL = 'LOCAL';
+
+enum Foo {
+  A = `${BAR}`,
+
+  B = LOCAL,
+  C = B,
+  D = C + 'BAR',
+
+  F = BAR,
+  G = 2 + BAR,
+
+  H = A,
+  I = H + BAR,
+  J = H
+}
 
 //// [bar.ts]
 export const BAR = 'bar';
@@ -11,7 +26,16 @@ export const BAR = 'bar';
 export const BAR = 'bar';
 //// [foo.js]
 import { BAR } from './bar';
+const LOCAL = 'LOCAL';
 var Foo;
 (function (Foo) {
     Foo["A"] = "bar";
+    Foo["B"] = "LOCAL";
+    Foo["C"] = "LOCAL";
+    Foo["D"] = "LOCALBAR";
+    Foo[Foo["F"] = "bar"] = "F";
+    Foo[Foo["G"] = "2bar"] = "G";
+    Foo["H"] = "bar";
+    Foo["I"] = "barbar";
+    Foo["J"] = "bar";
 })(Foo || (Foo = {}));

tests/baselines/reference/enumNoInitializerFollowsNonLiteralInitializer.errors.txt

@@ -31,4 +31,14 @@ bad.ts(4,5): error TS18056: Enum member following a non-literal numeric member m
         a = (2),
         b,
     }
+    enum E {
+        a,
+        b,
+        c = a,
+        d,
+        e = d | b,
+        f,
+        g = (f | a)! satisfies number as any,
+        h,
+    }
 

tests/baselines/reference/enumNoInitializerFollowsNonLiteralInitializer.js

@@ -28,6 +28,16 @@ enum D {
     a = (2),
     b,
 }
+enum E {
+    a,
+    b,
+    c = a,
+    d,
+    e = d | b,
+    f,
+    g = (f | a)! satisfies number as any,
+    h,
+}
 
 
 //// [helpers.js]
@@ -68,3 +78,14 @@ var D;
     D[D["a"] = 2] = "a";
     D[D["b"] = 3] = "b";
 })(D || (D = {}));
+var E;
+(function (E) {
+    E[E["a"] = 0] = "a";
+    E[E["b"] = 1] = "b";
+    E[E["c"] = 0] = "c";
+    E[E["d"] = 1] = "d";
+    E[E["e"] = 1] = "e";
+    E[E["f"] = 2] = "f";
+    E[E["g"] = 2] = "g";
+    E[E["h"] = 3] = "h";
+})(E || (E = {}));

tests/cases/compiler/computedEnumMemberSyntacticallyString.ts

@@ -10,4 +10,11 @@ enum Foo {
     C = (`${BAR}`),
     D = (`${BAR}}`) as string,
     E = `${BAR}`!,
+
+    F = BAR,
+    G = 2 + BAR,
+
+    H = A,
+    I = H + BAR,
+    J = H
 }