From 96388c35abf45d6107b2783a4536003693393cf3 Mon Sep 17 00:00:00 2001
From: Perryvw <perry.wesel@gmail.com>
Date: Tue, 17 Aug 2021 15:29:23 +0200
Subject: [PATCH 1/2] Throw when a required method is not present

---
 src/lualib/OptionalMethodCall.ts    |  3 +++
 src/transformation/visitors/call.ts |  6 ++++--
 test/unit/optionalChaining.spec.ts  | 11 +++++++++--
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/src/lualib/OptionalMethodCall.ts b/src/lualib/OptionalMethodCall.ts
index 8829e4a4d..5549a1c36 100644
--- a/src/lualib/OptionalMethodCall.ts
+++ b/src/lualib/OptionalMethodCall.ts
@@ -2,12 +2,15 @@ function __TS__OptionalMethodCall<TArgs extends any[], TReturn>(
     this: void,
     table: Record<string, (...args: [...TArgs]) => TReturn>,
     methodName: string,
+    isMethodOptional: boolean,
     ...args: [...TArgs]
 ): TReturn | undefined {
     if (table) {
         const method = table[methodName];
         if (method) {
             return method.call(table, ...args);
+        } else if (!isMethodOptional) {
+            throw `${methodName} is not a function`;
         }
     }
     return undefined;
diff --git a/src/transformation/visitors/call.ts b/src/transformation/visitors/call.ts
index 7add12ddc..b8036021e 100644
--- a/src/transformation/visitors/call.ts
+++ b/src/transformation/visitors/call.ts
@@ -161,6 +161,7 @@ export function transformContextualCallExpression(
                 node,
                 table,
                 lua.createStringLiteral(left.name.text, left.name),
+                lua.createBooleanLiteral(node.questionDotToken !== undefined), // Require method is present if no ?.() call
                 ...transformArguments(context, args, signature)
             );
         } else {
@@ -331,7 +332,7 @@ function wrapIfRequired(
     shouldWrapInTable: boolean,
     shouldWrapOptional: boolean,
     call: lua.CallExpression | lua.MethodCallExpression,
-    node: ts.Node
+    node: ts.CallExpression
 ): lua.Expression {
     const wrappedOptional = shouldWrapOptional ? wrapOptionalCall(context, call, node) : call;
     return shouldWrapInTable ? wrapInTable(wrappedOptional) : wrappedOptional;
@@ -340,7 +341,7 @@ function wrapIfRequired(
 function wrapOptionalCall(
     context: TransformationContext,
     call: lua.CallExpression | lua.MethodCallExpression,
-    node: ts.Node
+    node: ts.CallExpression
 ): lua.CallExpression {
     if (lua.isMethodCallExpression(call)) {
         return transformLuaLibFunction(
@@ -349,6 +350,7 @@ function wrapOptionalCall(
             node,
             call.prefixExpression,
             lua.createStringLiteral(call.name.text),
+            lua.createBooleanLiteral(node.questionDotToken !== undefined), // Require method is present if no ?.() call
             ...call.params
         );
     } else {
diff --git a/test/unit/optionalChaining.spec.ts b/test/unit/optionalChaining.spec.ts
index cf24b6702..69ecf9379 100644
--- a/test/unit/optionalChaining.spec.ts
+++ b/test/unit/optionalChaining.spec.ts
@@ -144,8 +144,8 @@ describe("optional chaining function calls", () => {
             const objWithMethods: typeWithOptional = {};
             const objWithMethods2: typeWithOptional = { a: { b: { c: () => 4 } } };
 
-            return { 
-                expectNil: objWithMethods.a?.b.c(), 
+            return {
+                expectNil: objWithMethods.a?.b.c(),
                 expectFour: objWithMethods2.a?.b.c()
             };
         `.expectToMatchJsResult();
@@ -167,4 +167,11 @@ describe("optional chaining function calls", () => {
             return [obj.a?.().b.c?.() ?? "nil", obj2.a?.().b.c?.() ?? "nil", obj3.a?.().b.c?.() ?? "nil"];
         `.expectToMatchJsResult();
     });
+
+    test("incorrect type, method is not a function", () => {
+        util.testFunction`
+            const obj: any = {};
+            obj?.foo();
+        `.expectToEqual(new util.ExecutionError("foo is not a function"));
+    });
 });

From 764f9d16950f95f21c00370dcf314cc5e262fe77 Mon Sep 17 00:00:00 2001
From: Perryvw <perry.wesel@gmail.com>
Date: Fri, 20 Aug 2021 18:49:53 +0200
Subject: [PATCH 2/2] Add issue link to test

---
 test/unit/optionalChaining.spec.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/unit/optionalChaining.spec.ts b/test/unit/optionalChaining.spec.ts
index 69ecf9379..9763a91c6 100644
--- a/test/unit/optionalChaining.spec.ts
+++ b/test/unit/optionalChaining.spec.ts
@@ -168,6 +168,7 @@ describe("optional chaining function calls", () => {
         `.expectToMatchJsResult();
     });
 
+    // https://github.com/TypeScriptToLua/TypeScriptToLua/issues/1085
     test("incorrect type, method is not a function", () => {
         util.testFunction`
             const obj: any = {};