From cc198dfdef2b493fe54ac60aaa3113c9d1daad5c Mon Sep 17 00:00:00 2001
From: lightpacerabbit <lightpacerabbit@gmail.com>
Date: Tue, 23 Jul 2019 18:44:36 +0800
Subject: [PATCH 1/3] Add edge test case. That makes unit test for
 `string.indexOf` failure.

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

diff --git a/test/unit/string.spec.ts b/test/unit/string.spec.ts
index 8768818cf..9590c478d 100644
--- a/test/unit/string.spec.ts
+++ b/test/unit/string.spec.ts
@@ -132,6 +132,7 @@ test.each([
     { inp: "hello test", searchValue: "t" },
     { inp: "hello test", searchValue: "h" },
     { inp: "hello test", searchValue: "invalid" },
+    { inp: "hello.test", searchValue: "." },
 ])("string.indexOf (%p)", ({ inp, searchValue }) => {
     const result = util.transpileAndExecute(`return "${inp}".indexOf("${searchValue}")`);
 

From 81bc21d5b68979abf558de3ff9826ef17d1d098b Mon Sep 17 00:00:00 2001
From: lightpacerabbit <lightpacerabbit@gmail.com>
Date: Tue, 23 Jul 2019 18:47:40 +0800
Subject: [PATCH 2/3] Fix transform `string.indexOf` with out `plain`
 parameter.

---
 src/LuaTransformer.ts | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/LuaTransformer.ts b/src/LuaTransformer.ts
index 4138f2af2..e6b771f03 100644
--- a/src/LuaTransformer.ts
+++ b/src/LuaTransformer.ts
@@ -4352,7 +4352,14 @@ export class LuaTransformer {
             case "indexOf":
                 const stringExpression =
                     node.arguments.length === 1
-                        ? this.createStringCall("find", node, caller, params[0])
+                        ? this.createStringCall(
+                              "find",
+                              node,
+                              caller,
+                              params[0],
+                              tstl.createNilLiteral(),
+                              tstl.createBooleanLiteral(true)
+                          )
                         : this.createStringCall(
                               "find",
                               node,

From 24825a18c9ee8e954938b53a8c941687b30766e6 Mon Sep 17 00:00:00 2001
From: lightpacerabbit <lightpacerabbit@gmail.com>
Date: Wed, 24 Jul 2019 11:14:14 +0800
Subject: [PATCH 3/3] Fix make two expressions collapsed to a single call

---
 src/LuaTransformer.ts | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/src/LuaTransformer.ts b/src/LuaTransformer.ts
index e6b771f03..ac8f49578 100644
--- a/src/LuaTransformer.ts
+++ b/src/LuaTransformer.ts
@@ -4350,24 +4350,14 @@ export class LuaTransformer {
             case "concat":
                 return this.transformLuaLibFunction(LuaLibFeature.StringConcat, node, caller, ...params);
             case "indexOf":
-                const stringExpression =
-                    node.arguments.length === 1
-                        ? this.createStringCall(
-                              "find",
-                              node,
-                              caller,
-                              params[0],
-                              tstl.createNilLiteral(),
-                              tstl.createBooleanLiteral(true)
-                          )
-                        : this.createStringCall(
-                              "find",
-                              node,
-                              caller,
-                              params[0],
-                              this.expressionPlusOne(params[1]),
-                              tstl.createBooleanLiteral(true)
-                          );
+                const stringExpression = this.createStringCall(
+                    "find",
+                    node,
+                    caller,
+                    params[0],
+                    params[1] ? this.expressionPlusOne(params[1]) : tstl.createNilLiteral(),
+                    tstl.createBooleanLiteral(true)
+                );
 
                 return tstl.createParenthesizedExpression(
                     tstl.createBinaryExpression(