Allow special element access assignments to create declarations

src/compiler/checker.ts

@@ -3033,7 +3033,7 @@ namespace ts {
                     return getSymbolOfNode(d.parent);
                 }
                 if (isClassExpression(d) && isBinaryExpression(d.parent) && d.parent.operatorToken.kind === SyntaxKind.EqualsToken && isAccessExpression(d.parent.left) && isEntityNameExpression(d.parent.left.expression)) {
-                    if (isModuleExportsPropertyAccessExpression(d.parent.left) || isExportsIdentifier(d.parent.left.expression)) {
+                    if (isModuleExportsAccessExpression(d.parent.left) || isExportsIdentifier(d.parent.left.expression)) {
                         return getSymbolOfNode(getSourceFileOfNode(d));
                     }
                     checkExpressionCached(d.parent.left.expression);
@@ -4869,6 +4869,15 @@ namespace ts {
                 }
             }
 
+            function getPropertyNameNodeForSymbol(symbol: Symbol, context: NodeBuilderContext) {
+                const fromNameType = getPropertyNameNodeForSymbolFromNameType(symbol, context);
+                if (fromNameType) {
+                    return fromNameType;
+                }
+                const rawName = unescapeLeadingUnderscores(symbol.escapedName);
+                return createPropertyNameNodeForIdentifierOrLiteral(rawName);
+            }
+
             // See getNameForSymbolFromNameType for a stringy equivalent
             function getPropertyNameNodeForSymbolFromNameType(symbol: Symbol, context: NodeBuilderContext) {
                 const nameType = symbol.nameType;
@@ -4881,14 +4890,18 @@ namespace ts {
                         if (isNumericLiteralName(name) && startsWith(name, "-")) {
                             return createComputedPropertyName(createLiteral(+name));
                         }
-                        return isIdentifierText(name, compilerOptions.target) ? createIdentifier(name) : createLiteral(isNumericLiteralName(name) ? +name : name) as StringLiteral | NumericLiteral;
+                        return createPropertyNameNodeForIdentifierOrLiteral(name);
                     }
                     if (nameType.flags & TypeFlags.UniqueESSymbol) {
                         return createComputedPropertyName(symbolToExpression((<UniqueESSymbolType>nameType).symbol, context, SymbolFlags.Value));
                     }
                 }
             }
 
+            function createPropertyNameNodeForIdentifierOrLiteral(name: string) {
+                return isIdentifierText(name, compilerOptions.target) ? createIdentifier(name) : createLiteral(isNumericLiteralName(name) ? +name : name) as StringLiteral | NumericLiteral;
+            }
+
             function cloneNodeBuilderContext(context: NodeBuilderContext): NodeBuilderContext {
                 const initial: NodeBuilderContext = { ...context };
                 // Make type parameters created within this context not consume the name outside this context
@@ -5764,8 +5777,7 @@ namespace ts {
                             return [];
                         }
                         const staticFlag = isStatic ? ModifierFlags.Static : 0;
-                        const rawName = unescapeLeadingUnderscores(p.escapedName);
-                        const name = getPropertyNameNodeForSymbolFromNameType(p, context) || createIdentifier(rawName);
+                        const name = getPropertyNameNodeForSymbol(p, context);
                         const firstPropertyLikeDecl = find(p.declarations, or(isPropertyDeclaration, isAccessor, isVariableDeclaration, isPropertySignature, isBinaryExpression, isPropertyAccessExpression));
                         if (p.flags & SymbolFlags.Accessor && useAccessors) {
                             const result: AccessorDeclaration[] = [];
@@ -6861,13 +6873,15 @@ namespace ts {
             let types: Type[] | undefined;
             for (const declaration of symbol.declarations) {
                 const expression = (isBinaryExpression(declaration) || isCallExpression(declaration)) ? declaration :
-                    isPropertyAccessExpression(declaration) ? isBinaryExpression(declaration.parent) ? declaration.parent : declaration :
+                    isAccessExpression(declaration) ? isBinaryExpression(declaration.parent) ? declaration.parent : declaration :
                     undefined;
                 if (!expression) {
                     continue; // Non-assignment declaration merged in (eg, an Identifier to mark the thing as a namespace) - skip over it and pull type info from elsewhere
                 }
 
-                const kind = isPropertyAccessExpression(expression) ? getAssignmentDeclarationPropertyAccessKind(expression) : getAssignmentDeclarationKind(expression);
+                const kind = isAccessExpression(expression)
+                    ? getAssignmentDeclarationPropertyAccessKind(expression)
+                    : getAssignmentDeclarationKind(expression);
                 if (kind === AssignmentDeclarationKind.ThisProperty) {
                     if (isDeclarationInConstructor(expression)) {
                         definedInConstructor = true;
@@ -7242,12 +7256,15 @@ namespace ts {
             else if (
                 isBinaryExpression(declaration) ||
                 (isInJSFile(declaration) &&
-                (isCallExpression(declaration) || isPropertyAccessExpression(declaration) && isBinaryExpression(declaration.parent)))) {
+                (isCallExpression(declaration) || (isPropertyAccessExpression(declaration) || isBindableStaticElementAccessExpression(declaration)) && isBinaryExpression(declaration.parent)))) {
                 type = getWidenedTypeForAssignmentDeclaration(symbol);
             }
             else if (isJSDocPropertyLikeTag(declaration)
                 || isPropertyAccessExpression(declaration)
+                || isElementAccessExpression(declaration)
                 || isIdentifier(declaration)
+                || isStringLiteralLike(declaration)
+                || isNumericLiteral(declaration)
                 || isClassDeclaration(declaration)
                 || isFunctionDeclaration(declaration)
                 || (isMethodDeclaration(declaration) && !isObjectLiteralMethod(declaration))
@@ -7428,7 +7445,8 @@ namespace ts {
                 return anyType;
             }
             else if (declaration.kind === SyntaxKind.BinaryExpression ||
-                     declaration.kind === SyntaxKind.PropertyAccessExpression && declaration.parent.kind === SyntaxKind.BinaryExpression) {
+                    (declaration.kind === SyntaxKind.PropertyAccessExpression || declaration.kind === SyntaxKind.ElementAccessExpression) &&
+                    declaration.parent.kind === SyntaxKind.BinaryExpression) {
                 return getWidenedTypeForAssignmentDeclaration(symbol);
             }
             else if (symbol.flags & SymbolFlags.ValueModule && declaration && isSourceFile(declaration) && declaration.commonJsModuleIndicator) {
@@ -32028,7 +32046,7 @@ namespace ts {
                     return node;
                 case SyntaxKind.PropertyAccessExpression:
                     do {
-                        if (isModuleExportsPropertyAccessExpression(node.expression)) {
+                        if (isModuleExportsAccessExpression(node.expression)) {
                             return node.name;
                         }
                         node = node.expression;

src/compiler/emitter.ts

@@ -2260,7 +2260,7 @@ namespace ts {
                 return !expression.numericLiteralFlags && !stringContains(text, tokenToString(SyntaxKind.DotToken)!) &&
                     (!dotHasTrivia || printerOptions.removeComments);
             }
-            else if (isPropertyAccessExpression(expression) || isElementAccessExpression(expression)) {
+            else if (isAccessExpression(expression)) {
                 // check if constant enum value is integer
                 const constantValue = getConstantValue(expression);
                 // isFinite handles cases when constantValue is undefined

src/compiler/types.ts

@@ -1301,7 +1301,7 @@ namespace ts {
         literal: BooleanLiteral | LiteralExpression | PrefixUnaryExpression;
     }
 
-    export interface StringLiteral extends LiteralExpression {
+    export interface StringLiteral extends LiteralExpression, Declaration {
         kind: SyntaxKind.StringLiteral;
         /* @internal */ textSourceNode?: Identifier | StringLiteralLike | NumericLiteral; // Allows a StringLiteral to get its text from another node (used by transforms).
         /** Note: this is only set when synthesizing a node, not during parsing. */
@@ -1688,7 +1688,7 @@ namespace ts {
         kind: SyntaxKind.RegularExpressionLiteral;
     }
 
-    export interface NoSubstitutionTemplateLiteral extends LiteralExpression, TemplateLiteralLikeNode {
+    export interface NoSubstitutionTemplateLiteral extends LiteralExpression, TemplateLiteralLikeNode, Declaration {
         kind: SyntaxKind.NoSubstitutionTemplateLiteral;
     }
 
@@ -1717,7 +1717,7 @@ namespace ts {
         NumericLiteralFlags = Scientific | Octal | HexSpecifier | BinaryOrOctalSpecifier | ContainsSeparator
     }
 
-    export interface NumericLiteral extends LiteralExpression {
+    export interface NumericLiteral extends LiteralExpression, Declaration {
         kind: SyntaxKind.NumericLiteral;
         /* @internal */
         numericLiteralFlags: TokenFlags;
@@ -1837,7 +1837,33 @@ namespace ts {
     }
 
     /** @internal */
-    export type BindableObjectDefinePropertyCall = CallExpression & { arguments: { 0: EntityNameExpression, 1: StringLiteralLike | NumericLiteral, 2: ObjectLiteralExpression } };
+    export type BindableObjectDefinePropertyCall = CallExpression & { arguments: { 0: BindableStaticNameExpression, 1: StringLiteralLike | NumericLiteral, 2: ObjectLiteralExpression } };
+    /** @internal */
+    export type BindableStaticNameExpression = EntityNameExpression | BindableStaticElementAccessExpression;
+    /** @internal */
+    export type LiteralLikeElementAccessExpression = ElementAccessExpression & Declaration & {
+        argumentExpression: StringLiteralLike | NumericLiteral;
+    };
+    /** @internal */
+    export type BindableStaticElementAccessExpression = LiteralLikeElementAccessExpression & {
+        expression: BindableStaticNameExpression;
+    };
+    /** @internal */
+    export type BindableElementAccessExpression = ElementAccessExpression & {
+        expression: BindableStaticNameExpression;
+    };
+    /** @internal */
+    export type BindableStaticAccessExpression = PropertyAccessEntityNameExpression | BindableStaticElementAccessExpression;
+    /** @internal */
+    export type BindableAccessExpression = PropertyAccessEntityNameExpression | BindableElementAccessExpression;
+    /** @internal */
+    export interface BindableStaticPropertyAssignmentExpression extends BinaryExpression {
+        left: BindableStaticAccessExpression;
+    }
+    /** @internal */
+    export interface BindablePropertyAssignmentExpression extends BinaryExpression {
+        left: BindableAccessExpression;
+    }
 
     // see: https://tc39.github.io/ecma262/#prod-SuperCall
     export interface SuperCall extends CallExpression {