Nested assignment to a require alias isn't a declaration (microsoft#40186)

This is not something we can type correctly, and doesn't work in
Typescript either. Better to ignore it in JS.

Author: sandersn

src/compiler/binder.ts

@@ -2974,6 +2974,10 @@ namespace ts {
             if (!isInJSFile(node) && !isFunctionSymbol(parentSymbol)) {
                 return;
             }
+            const rootExpr = getLeftmostAccessExpression(node.left);
+            if (isIdentifier(rootExpr) && lookupSymbolForName(container, rootExpr.escapedText)!?.flags & SymbolFlags.Alias) {
+                return;
+            }
             // Fix up parent pointers since we're going to use these nodes before we bind into them
             setParent(node.left, node);
             setParent(node.right, node);

src/compiler/checker.ts

@@ -2416,7 +2416,7 @@ namespace ts {
 
         function getTargetOfImportEqualsDeclaration(node: ImportEqualsDeclaration | VariableDeclaration, dontResolveAlias: boolean): Symbol | undefined {
             if (isVariableDeclaration(node) && node.initializer && isPropertyAccessExpression(node.initializer)) {
-                const name = (getLeftmostPropertyAccessExpression(node.initializer.expression) as CallExpression).arguments[0] as StringLiteral;
+                const name = (getLeftmostAccessExpression(node.initializer.expression) as CallExpression).arguments[0] as StringLiteral;
                 return isIdentifier(node.initializer.name)
                     ? resolveSymbol(getPropertyOfType(resolveExternalModuleTypeByLiteral(name), node.initializer.name.escapedText))
                     : undefined;

src/compiler/utilities.ts

@@ -1869,7 +1869,7 @@ namespace ts {
 
     export function getExternalModuleRequireArgument(node: Node) {
         return isRequireVariableDeclaration(node, /*requireStringLiteralLikeArgument*/ true)
-            && (getLeftmostPropertyAccessExpression(node.initializer) as CallExpression).arguments[0] as StringLiteral;
+            && (getLeftmostAccessExpression(node.initializer) as CallExpression).arguments[0] as StringLiteral;
     }
 
     export function isInternalModuleImportEqualsDeclaration(node: Node): node is ImportEqualsDeclaration {
@@ -1940,7 +1940,7 @@ namespace ts {
     export function isRequireVariableDeclaration(node: Node, requireStringLiteralLikeArgument: boolean): node is VariableDeclaration;
     export function isRequireVariableDeclaration(node: Node, requireStringLiteralLikeArgument: boolean): node is VariableDeclaration {
         node = getRootDeclaration(node);
-        return isVariableDeclaration(node) && !!node.initializer && isRequireCall(getLeftmostPropertyAccessExpression(node.initializer), requireStringLiteralLikeArgument);
+        return isVariableDeclaration(node) && !!node.initializer && isRequireCall(getLeftmostAccessExpression(node.initializer), requireStringLiteralLikeArgument);
     }
 
     export function isRequireVariableStatement(node: Node, requireStringLiteralLikeArgument = true): node is RequireVariableStatement {
@@ -5463,8 +5463,8 @@ namespace ts {
         return node.kind === SyntaxKind.NamedImports || node.kind === SyntaxKind.NamedExports;
     }
 
-    export function getLeftmostPropertyAccessExpression(expr: Expression): Expression {
-        while (isPropertyAccessExpression(expr)) {
+    export function getLeftmostAccessExpression(expr: Expression): Expression {
+        while (isAccessExpression(expr)) {
             expr = expr.expression;
         }
         return expr;

tests/baselines/reference/namespaceAssignmentToRequireAlias.errors.txt

@@ -0,0 +1,14 @@
+tests/cases/conformance/salsa/bug40140.js(1,19): error TS7016: Could not find a declaration file for module 'untyped'. 'tests/cases/conformance/salsa/node_modules/untyped/index.js' implicitly has an 'any' type.
+
+
+==== tests/cases/conformance/salsa/bug40140.js (1 errors) ====
+    const u = require('untyped');
+                      ~~~~~~~~~
+!!! error TS7016: Could not find a declaration file for module 'untyped'. 'tests/cases/conformance/salsa/node_modules/untyped/index.js' implicitly has an 'any' type.
+    u.assignment.nested = true
+    u.noError()
+    
+    
+==== tests/cases/conformance/salsa/node_modules/untyped/index.js (0 errors) ====
+    module.exports = {}
+    

tests/baselines/reference/namespaceAssignmentToRequireAlias.js

@@ -0,0 +1,21 @@
+//// [tests/cases/conformance/salsa/namespaceAssignmentToRequireAlias.ts] ////
+
+//// [index.js]
+module.exports = {}
+
+//// [bug40140.js]
+const u = require('untyped');
+u.assignment.nested = true
+u.noError()
+
+
+
+//// [bug40140.js]
+"use strict";
+var u = require('untyped');
+u.assignment.nested = true;
+u.noError();
+
+
+//// [bug40140.d.ts]
+export {};

tests/baselines/reference/namespaceAssignmentToRequireAlias.symbols

@@ -0,0 +1,12 @@
+=== tests/cases/conformance/salsa/bug40140.js ===
+const u = require('untyped');
+>u : Symbol(u, Decl(bug40140.js, 0, 5))
+>require : Symbol(require)
+
+u.assignment.nested = true
+>u : Symbol(u, Decl(bug40140.js, 0, 5))
+
+u.noError()
+>u : Symbol(u, Decl(bug40140.js, 0, 5))
+
+

tests/baselines/reference/namespaceAssignmentToRequireAlias.types

@@ -0,0 +1,23 @@
+=== tests/cases/conformance/salsa/bug40140.js ===
+const u = require('untyped');
+>u : any
+>require('untyped') : any
+>require : any
+>'untyped' : "untyped"
+
+u.assignment.nested = true
+>u.assignment.nested = true : true
+>u.assignment.nested : any
+>u.assignment : any
+>u : any
+>assignment : any
+>nested : any
+>true : true
+
+u.noError()
+>u.noError() : any
+>u.noError : any
+>u : any
+>noError : any
+
+

tests/cases/conformance/salsa/namespaceAssignmentToRequireAlias.ts

@@ -0,0 +1,13 @@
+// @allowJs: true
+// @checkJs: true
+// @strict: true
+// @outDir: out
+// @declaration: true
+// @filename: node_modules/untyped/index.js
+module.exports = {}
+
+// @filename: bug40140.js
+const u = require('untyped');
+u.assignment.nested = true
+u.noError()
+