Fix compiler crash with object rest in catch binding (#31522)

Author: rbuckton

src/compiler/checker.ts

@@ -30169,12 +30169,17 @@ namespace ts {
             return undefined;
         }
 
+        function isSymbolOfDestructuredElementOfCatchBinding(symbol: Symbol) {
+            return isBindingElement(symbol.valueDeclaration)
+                && walkUpBindingElementsAndPatterns(symbol.valueDeclaration).parent.kind === SyntaxKind.CatchClause;
+        }
+
         function isSymbolOfDeclarationWithCollidingName(symbol: Symbol): boolean {
             if (symbol.flags & SymbolFlags.BlockScoped && !isSourceFile(symbol.valueDeclaration)) {
                 const links = getSymbolLinks(symbol);
                 if (links.isDeclarationWithCollidingName === undefined) {
                     const container = getEnclosingBlockScopeContainer(symbol.valueDeclaration);
-                    if (isStatementWithLocals(container)) {
+                    if (isStatementWithLocals(container) || isSymbolOfDestructuredElementOfCatchBinding(symbol)) {
                         const nodeLinks = getNodeLinks(symbol.valueDeclaration);
                         if (resolveName(container.parent, symbol.escapedName, SymbolFlags.Value, /*nameNotFoundMessage*/ undefined, /*nameArg*/ undefined, /*isUse*/ false)) {
                             // redeclaration - always should be renamed

src/compiler/transformers/es2018.ts

@@ -77,6 +77,8 @@ namespace ts {
                     return visitObjectLiteralExpression(node as ObjectLiteralExpression);
                 case SyntaxKind.BinaryExpression:
                     return visitBinaryExpression(node as BinaryExpression, noDestructuringValue);
+                case SyntaxKind.CatchClause:
+                    return visitCatchClause(node as CatchClause);
                 case SyntaxKind.VariableDeclaration:
                     return visitVariableDeclaration(node as VariableDeclaration);
                 case SyntaxKind.ForOfStatement:
@@ -272,6 +274,28 @@ namespace ts {
             return visitEachChild(node, visitor, context);
         }
 
+        function visitCatchClause(node: CatchClause) {
+            if (node.variableDeclaration &&
+                isBindingPattern(node.variableDeclaration.name) &&
+                node.variableDeclaration.name.transformFlags & TransformFlags.ContainsObjectRestOrSpread) {
+                const name = getGeneratedNameForNode(node.variableDeclaration.name);
+                const updatedDecl = updateVariableDeclaration(node.variableDeclaration, node.variableDeclaration.name, /*type*/ undefined, name);
+                const visitedBindings = flattenDestructuringBinding(updatedDecl, visitor, context, FlattenLevel.ObjectRest);
+                let block = visitNode(node.block, visitor, isBlock);
+                if (some(visitedBindings)) {
+                    block = updateBlock(block, [
+                        createVariableStatement(/*modifiers*/ undefined, visitedBindings),
+                        ...block.statements,
+                    ]);
+                }
+                return updateCatchClause(
+                    node,
+                    updateVariableDeclaration(node.variableDeclaration, name, /*type*/ undefined, /*initializer*/ undefined),
+                    block);
+            }
+            return visitEachChild(node, visitor, context);
+        }
+
         /**
          * Visits a VariableDeclaration node with a binding pattern.
          *

tests/baselines/reference/objectRestCatchES5.js

@@ -0,0 +1,21 @@
+//// [objectRestCatchES5.ts]
+let a = 1, b = 2;
+try {} catch ({ a, ...b }) {}
+
+//// [objectRestCatchES5.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
+        t[p] = s[p];
+    if (s != null && typeof Object.getOwnPropertySymbols === "function")
+        for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) {
+            if (e.indexOf(p[i]) < 0 && Object.prototype.propertyIsEnumerable.call(s, p[i]))
+                t[p[i]] = s[p[i]];
+        }
+    return t;
+};
+var a = 1, b = 2;
+try { }
+catch (_a) {
+    var a_1 = _a.a, b_1 = __rest(_a, ["a"]);
+}

tests/baselines/reference/objectRestCatchES5.symbols

@@ -0,0 +1,9 @@
+=== tests/cases/conformance/types/rest/objectRestCatchES5.ts ===
+let a = 1, b = 2;
+>a : Symbol(a, Decl(objectRestCatchES5.ts, 0, 3))
+>b : Symbol(b, Decl(objectRestCatchES5.ts, 0, 10))
+
+try {} catch ({ a, ...b }) {}
+>a : Symbol(a, Decl(objectRestCatchES5.ts, 1, 15))
+>b : Symbol(b, Decl(objectRestCatchES5.ts, 1, 18))
+

tests/baselines/reference/objectRestCatchES5.types

@@ -0,0 +1,11 @@
+=== tests/cases/conformance/types/rest/objectRestCatchES5.ts ===
+let a = 1, b = 2;
+>a : number
+>1 : 1
+>b : number
+>2 : 2
+
+try {} catch ({ a, ...b }) {}
+>a : any
+>b : any
+

tests/cases/conformance/types/rest/objectRestCatchES5.ts

@@ -0,0 +1,2 @@
+let a = 1, b = 2;
+try {} catch ({ a, ...b }) {}