one-line: avoid crash on parse error

src/rules/oneLineRule.ts

@@ -97,7 +97,10 @@ class OneLineWalker extends Lint.AbstractWalker<Options> {
                 case ts.SyntaxKind.InterfaceDeclaration:
                 case ts.SyntaxKind.ClassDeclaration:
                 case ts.SyntaxKind.ClassExpression: {
-                    this.check(getChildOfKind(node, ts.SyntaxKind.OpenBraceToken, sourceFile)!);
+                    const openBrace = getChildOfKind(node, ts.SyntaxKind.OpenBraceToken, sourceFile);
+                    if (openBrace !== undefined) {
+                        this.check(openBrace);
+                    }
                     break;
                 }
                 case ts.SyntaxKind.IfStatement: {

test/rules/one-line/all/test.ts.fix

@@ -136,3 +136,16 @@ if (true) {
 } else {
     false;
 }
+
+// don't crash on parse error
+interface InvalidInterface = {
+  foo: string,
+}
+
+class InvalidClass = {
+  foo: string,
+}
+
+foo = class InvalidClassExpression = {
+  foo: string,
+}

test/rules/one-line/all/test.ts.lint

@@ -179,3 +179,16 @@ if (true) {
  ~~~~   [missing whitespace]
     false;
 }
+
+// don't crash on parse error
+interface InvalidInterface = {
+  foo: string,
+}
+
+class InvalidClass = {
+  foo: string,
+}
+
+foo = class InvalidClassExpression = {
+  foo: string,
+}