From ba82d8775984bcc7643871ab3a33832a9202ef88 Mon Sep 17 00:00:00 2001
From: Filip Sajdak <filip.sajdak@siili.com>
Date: Sat, 1 Oct 2022 18:31:21 +0200
Subject: [PATCH] Fix to_string to call cpp2::to_string

Calling std::to_string makes it impossible to use to_string
on optional that contains std::string.

The solution is to call cpp2::to_string instead of std::to_string.

Added examples of use in regression tests with results of execution.
---
 include/cpp2util.h                                  |  2 +-
 regression-tests/mixed-string-interpolation.cpp2    |  3 +++
 .../test-results/mixed-string-interpolation.cpp     |  3 +++
 .../test-results/mixed-string-interpolation.cpp2    | 13 +++++++++++++
 4 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 regression-tests/test-results/mixed-string-interpolation.cpp2

diff --git a/include/cpp2util.h b/include/cpp2util.h
index c42d59c59..dbb04e0c3 100644
--- a/include/cpp2util.h
+++ b/include/cpp2util.h
@@ -748,7 +748,7 @@ inline auto to_string(std::string const& s) -> std::string const&
 template<typename T>
 inline auto to_string(std::optional<T> const& o) -> std::string {
     if (o.has_value()) {
-        return std::to_string(o.value());
+        return cpp2::to_string(o.value());
     }
     return "(empty)";
 }
diff --git a/regression-tests/mixed-string-interpolation.cpp2 b/regression-tests/mixed-string-interpolation.cpp2
index 2cc2d64b3..992019982 100644
--- a/regression-tests/mixed-string-interpolation.cpp2
+++ b/regression-tests/mixed-string-interpolation.cpp2
@@ -7,4 +7,7 @@ main: () -> int = {
 
     b = 42;
     std::cout << "a^2 + b = (a * a + b.value())$\n";
+
+    os: std::optional<std::string> = "testing";
+    std::cout << "os = (os)$\n";
 }
diff --git a/regression-tests/test-results/mixed-string-interpolation.cpp b/regression-tests/test-results/mixed-string-interpolation.cpp
index 3f1e438d7..47537c547 100644
--- a/regression-tests/test-results/mixed-string-interpolation.cpp
+++ b/regression-tests/test-results/mixed-string-interpolation.cpp
@@ -17,4 +17,7 @@
 
     b = 42;
     std::cout << "a^2 + b = " + cpp2::to_string(a * a + b.value()) + "\n";
+
+    std::optional<std::string> os { "testing" }; 
+    std::cout << "os = " + cpp2::to_string(os) + "\n";
 }
diff --git a/regression-tests/test-results/mixed-string-interpolation.cpp2 b/regression-tests/test-results/mixed-string-interpolation.cpp2
new file mode 100644
index 000000000..992019982
--- /dev/null
+++ b/regression-tests/test-results/mixed-string-interpolation.cpp2
@@ -0,0 +1,13 @@
+#include <iostream>
+
+main: () -> int = {
+    a := 2;
+    b: std::optional<int> = ();
+    std::cout << "a = (a)$, b = (b)$\n";
+
+    b = 42;
+    std::cout << "a^2 + b = (a * a + b.value())$\n";
+
+    os: std::optional<std::string> = "testing";
+    std::cout << "os = (os)$\n";
+}