Don't crash on non-literal computed property names during getPropertyAssignment (#48079)

Author: jakebailey

src/compiler/utilities.ts

@@ -987,7 +987,7 @@ namespace ts {
         return name.kind === SyntaxKind.ComputedPropertyName && !isStringOrNumericLiteralLike(name.expression);
     }
 
-    export function getTextOfPropertyName(name: PropertyName | NoSubstitutionTemplateLiteral): __String {
+    export function tryGetTextOfPropertyName(name: PropertyName | NoSubstitutionTemplateLiteral): __String | undefined {
         switch (name.kind) {
             case SyntaxKind.Identifier:
             case SyntaxKind.PrivateIdentifier:
@@ -998,12 +998,16 @@ namespace ts {
                 return escapeLeadingUnderscores(name.text);
             case SyntaxKind.ComputedPropertyName:
                 if (isStringOrNumericLiteralLike(name.expression)) return escapeLeadingUnderscores(name.expression.text);
-                return Debug.fail("Text of property name cannot be read from non-literal-valued ComputedPropertyNames");
+                return undefined;
             default:
                 return Debug.assertNever(name);
         }
     }
 
+    export function getTextOfPropertyName(name: PropertyName | NoSubstitutionTemplateLiteral): __String {
+        return Debug.checkDefined(tryGetTextOfPropertyName(name));
+    }
+
     export function entityNameToString(name: EntityNameOrEntityNameExpression | JSDocMemberName | JsxTagNameExpression | PrivateIdentifier): string {
         switch (name.kind) {
             case SyntaxKind.ThisKeyword:
@@ -1573,7 +1577,7 @@ namespace ts {
     export function getPropertyAssignment(objectLiteral: ObjectLiteralExpression, key: string, key2?: string): readonly PropertyAssignment[] {
         return objectLiteral.properties.filter((property): property is PropertyAssignment => {
             if (property.kind === SyntaxKind.PropertyAssignment) {
-                const propName = getTextOfPropertyName(property.name);
+                const propName = tryGetTextOfPropertyName(property.name);
                 return key === propName || (!!key2 && key2 === propName);
             }
             return false;

src/harness/client.ts

@@ -110,14 +110,12 @@ namespace ts.server {
                 }
             }
 
-            // verify the sequence numbers
-            Debug.assert(response.request_seq === request.seq, "Malformed response: response sequence number did not match request sequence number.");
-
             // unmarshal errors
             if (!response.success) {
                 throw new Error("Error " + response.message);
             }
 
+            Debug.assert(response.request_seq === request.seq, "Malformed response: response sequence number did not match request sequence number.");
             Debug.assert(expectEmptyBody || !!response.body, "Malformed response: Unexpected empty response body.");
             Debug.assert(!expectEmptyBody || !response.body, "Malformed response: Unexpected non-empty response body.");
 

tests/cases/fourslash/server/tsconfigComputedPropertyError.ts

@@ -0,0 +1,12 @@
+/// <reference path="../fourslash.ts"/>
+
+// @filename: tsconfig.json
+////{
+////    ["oops!" + 42]: "true",
+////    "files": [
+////        "nonexistentfile.ts"
+////    ],
+////    "compileOnSave": true
+////}
+
+verify.getSemanticDiagnostics([]);