maint(clang-tidy): Enable cpp-coreguideline slicing checks (#3210)

* maint(clang-tidy): add a clang-tidy slicing check

* Add self + touch up readme

* Fix typo

.clang-tidy

@@ -3,6 +3,7 @@ FormatStyle: file
 Checks: '
 Checks: '
 *bugprone*,
 *bugprone*,
 cppcoreguidelines-init-variables,
 cppcoreguidelines-init-variables,
+cppcoreguidelines-slicing,
 clang-analyzer-optin.cplusplus.VirtualCall,
 clang-analyzer-optin.cplusplus.VirtualCall,
 llvm-namespace-comment,
 llvm-namespace-comment,
 misc-misplaced-const,
 misc-misplaced-const,

README.rst

@@ -134,9 +134,9 @@ About
 This project was created by `Wenzel
 This project was created by `Wenzel
 Jakob <http://rgl.epfl.ch/people/wjakob>`_. Significant features and/or
 Jakob <http://rgl.epfl.ch/people/wjakob>`_. Significant features and/or
 improvements to the code were contributed by Jonas Adler, Lori A. Burns,
 improvements to the code were contributed by Jonas Adler, Lori A. Burns,
-Sylvain Corlay, Eric Cousineau, Ralf Grosse-Kunstleve, Trent Houliston, Axel
+Sylvain Corlay, Eric Cousineau, Aaron Gokaslan, Ralf Grosse-Kunstleve, Trent Houliston, Axel
 Huebl, @hulucc, Yannick Jadoul, Sergey Lyskov Johan Mabille, Tomasz Miąsko,
 Huebl, @hulucc, Yannick Jadoul, Sergey Lyskov Johan Mabille, Tomasz Miąsko,
-Dean Moldovan, Ben Pritchard, Jason Rhinelander, Boris Schäling,  Pim
+Dean Moldovan, Ben Pritchard, Jason Rhinelander, Boris Schäling, Pim
 Schellart, Henry Schreiner, Ivan Smirnov, Boris Staletic, and Patrick Stewart.
 Schellart, Henry Schreiner, Ivan Smirnov, Boris Staletic, and Patrick Stewart.
 
 
 We thank Google for a generous financial contribution to the continuous
 We thank Google for a generous financial contribution to the continuous

include/pybind11/pybind11.h

@@ -1664,7 +1664,7 @@ inline str enum_name(handle arg) {
 }
 }
 
 
 struct enum_base {
 struct enum_base {
-    enum_base(handle base, handle parent) : m_base(base), m_parent(parent) { }
+    enum_base(const handle &base, const handle &parent) : m_base(base), m_parent(parent) { }
 
 
     PYBIND11_NOINLINE void init(bool is_arithmetic, bool is_convertible) {
     PYBIND11_NOINLINE void init(bool is_arithmetic, bool is_convertible) {
         m_base.attr("__entries") = dict();
         m_base.attr("__entries") = dict();