Disable some clang conversion warnings in cpp2util.h and cppfront i…

…tself (#1212)

* Disable clang conversion warnings when compiling with -Wconversion

cppfront and cpp2util.h use signed integer types for indices and container sizes so disable signed-to-unsigned conversion warnings.

cppfront also uses implicit conversions from string literal to bool for:
`assert(!"message")`
so disable those warnings too.

* Update regression tests caused by line number changes in `cpp2util.h`

* Removed dependency on `!"string literal"`

* Address `.size()` narrowing warnings

Using the answer we recommend for everyone else, so model the right behavior here

---------

Co-authored-by: Herb Sutter <herb.sutter@gmail.com>

include/cpp2util.h

@@ -302,6 +302,12 @@
     #include <vector>
 #endif
 
+//  cpp2util.h uses signed integer types for indices and container sizes
+//  so disable clang signed-to-unsigned conversion warnings in this header.
+#ifdef __clang__
+    #pragma clang diagnostic push
+    #pragma clang diagnostic ignored "-Wsign-conversion"
+#endif
 
 //-----------------------------------------------------------------------
 //
@@ -2833,4 +2839,9 @@ using cpp2::cpp2_new;
     #define CPP2_REQUIRES_(...) requires (__VA_ARGS__)
 #endif
 
+//  Restore clang signed-to-unsigned conversion warnings
+#ifdef __clang__
+    #pragma clang diagnostic pop
 #endif
+
+#endif // CPP2_CPP2UTIL_H

regression-tests/test-results/apple-clang-15-c++2b/mixed-bounds-check.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(964) decltype(auto) cpp2::impl::assert_in_bounds(auto &&, std::source_location) [arg = 5, x:auto = std::vector<int>]: Bounds safety violation: out of bounds access attempt detected - attempted access at index 5, [min,max] range is [0,4]
+../../../include/cpp2util.h(970) decltype(auto) cpp2::impl::assert_in_bounds(auto &&, std::source_location) [arg = 5, x:auto = std::vector<int>]: Bounds safety violation: out of bounds access attempt detected - attempted access at index 5, [min,max] range is [0,4]

regression-tests/test-results/apple-clang-15-c++2b/mixed-bounds-safety-with-assert.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(776) : Bounds safety violation
+../../../include/cpp2util.h(782) : Bounds safety violation

regression-tests/test-results/apple-clang-15-c++2b/mixed-initialization-safety-3-contract-violation.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(776) : Contract violation: fill: value must contain at least count elements
+../../../include/cpp2util.h(782) : Contract violation: fill: value must contain at least count elements

regression-tests/test-results/apple-clang-15-c++2b/mixed-lifetime-safety-and-null-contracts.cpp.execution

@@ -1,2 +1,2 @@
 sending error to my framework... [dynamic null dereference attempt detected]
-from source location: ../../../include/cpp2util.h(855) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = int *&]
+from source location: ../../../include/cpp2util.h(861) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = int *&]

regression-tests/test-results/apple-clang-15-c++2b/pure2-assert-expected-not-null.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(855) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::expected<int, bool>]: Null safety violation: std::expected has an unexpected value
+../../../include/cpp2util.h(861) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::expected<int, bool>]: Null safety violation: std::expected has an unexpected value

regression-tests/test-results/apple-clang-15-c++2b/pure2-assert-optional-not-null.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(855) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::optional<int>]: Null safety violation: std::optional does not contain a value
+../../../include/cpp2util.h(861) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::optional<int>]: Null safety violation: std::optional does not contain a value

regression-tests/test-results/apple-clang-15-c++2b/pure2-assert-shared-ptr-not-null.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(855) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::shared_ptr<int>]: Null safety violation: std::shared_ptr is empty
+../../../include/cpp2util.h(861) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::shared_ptr<int>]: Null safety violation: std::shared_ptr is empty

regression-tests/test-results/apple-clang-15-c++2b/pure2-assert-unique-ptr-not-null.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(855) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::unique_ptr<int>]: Null safety violation: std::unique_ptr is empty
+../../../include/cpp2util.h(861) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::unique_ptr<int>]: Null safety violation: std::unique_ptr is empty

regression-tests/test-results/clang-15-c++20/mixed-bounds-check.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(964) decltype(auto) cpp2::impl::assert_in_bounds(auto &&, std::source_location) [arg = 5, x:auto = std::vector<int>]: Bounds safety violation: out of bounds access attempt detected - attempted access at index 5, [min,max] range is [0,4]
+../../../include/cpp2util.h(970) decltype(auto) cpp2::impl::assert_in_bounds(auto &&, std::source_location) [arg = 5, x:auto = std::vector<int>]: Bounds safety violation: out of bounds access attempt detected - attempted access at index 5, [min,max] range is [0,4]

regression-tests/test-results/clang-15-c++20/mixed-bounds-safety-with-assert.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(776) : Bounds safety violation
+../../../include/cpp2util.h(782) : Bounds safety violation

regression-tests/test-results/clang-15-c++20/mixed-initialization-safety-3-contract-violation.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(776) : Contract violation: fill: value must contain at least count elements
+../../../include/cpp2util.h(782) : Contract violation: fill: value must contain at least count elements

regression-tests/test-results/clang-15-c++20/mixed-lifetime-safety-and-null-contracts.cpp.execution

@@ -1,2 +1,2 @@
 sending error to my framework... [dynamic null dereference attempt detected]
-from source location: ../../../include/cpp2util.h(855) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = int *&]
+from source location: ../../../include/cpp2util.h(861) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = int *&]

regression-tests/test-results/clang-15-c++20/pure2-assert-optional-not-null.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(855) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::optional<int>]: Null safety violation: std::optional does not contain a value
+../../../include/cpp2util.h(861) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::optional<int>]: Null safety violation: std::optional does not contain a value

regression-tests/test-results/clang-15-c++20/pure2-assert-shared-ptr-not-null.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(855) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::shared_ptr<int>]: Null safety violation: std::shared_ptr is empty
+../../../include/cpp2util.h(861) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::shared_ptr<int>]: Null safety violation: std::shared_ptr is empty

regression-tests/test-results/clang-15-c++20/pure2-assert-unique-ptr-not-null.cpp.execution

@@ -1 +1 @@
-../../../include/cpp2util.h(855) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::unique_ptr<int>]: Null safety violation: std::unique_ptr is empty
+../../../include/cpp2util.h(861) decltype(auto) cpp2::impl::assert_not_null(auto &&, std::source_location) [arg:auto = std::unique_ptr<int>]: Null safety violation: std::unique_ptr is empty

regression-tests/test-results/gcc-13-c++2b/mixed-bugfix-for-ufcs-non-local.cpp.output

@@ -1,41 +1,41 @@
 In file included from mixed-bugfix-for-ufcs-non-local.cpp:6:
 ../../../include/cpp2util.h:2100:1: error: lambda-expression in template parameter type
- 2100 | constexpr auto is( X const& x ) -> bool
+ 2100 |     requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any> && !std::is_same_v<T,empty>)
       | ^
 ../../../include/cpp2util.h:2137:59: note: in expansion of macro ‘CPP2_UFCS_’
- 2137 | 
+ 2137 |     { return std::any_cast<T>( x ); }
       |                                                           ^         
 mixed-bugfix-for-ufcs-non-local.cpp2:13:12: note: in expansion of macro ‘CPP2_UFCS_NONLOCAL’
 mixed-bugfix-for-ufcs-non-local.cpp2:13:36: error: template argument 1 is invalid
 ../../../include/cpp2util.h:2100:1: error: lambda-expression in template parameter type
- 2100 | constexpr auto is( X const& x ) -> bool
+ 2100 |     requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any> && !std::is_same_v<T,empty>)
       | ^
 ../../../include/cpp2util.h:2137:59: note: in expansion of macro ‘CPP2_UFCS_’
- 2137 | 
+ 2137 |     { return std::any_cast<T>( x ); }
       |                                                           ^         
 mixed-bugfix-for-ufcs-non-local.cpp2:21:12: note: in expansion of macro ‘CPP2_UFCS_NONLOCAL’
 mixed-bugfix-for-ufcs-non-local.cpp2:21:36: error: template argument 1 is invalid
 ../../../include/cpp2util.h:2100:1: error: lambda-expression in template parameter type
- 2100 | constexpr auto is( X const& x ) -> bool
+ 2100 |     requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any> && !std::is_same_v<T,empty>)
       | ^
 ../../../include/cpp2util.h:2137:59: note: in expansion of macro ‘CPP2_UFCS_’
- 2137 | 
+ 2137 |     { return std::any_cast<T>( x ); }
       |                                                           ^         
 mixed-bugfix-for-ufcs-non-local.cpp2:31:12: note: in expansion of macro ‘CPP2_UFCS_NONLOCAL’
 mixed-bugfix-for-ufcs-non-local.cpp2:31:36: error: template argument 1 is invalid
 ../../../include/cpp2util.h:2100:1: error: lambda-expression in template parameter type
- 2100 | constexpr auto is( X const& x ) -> bool
+ 2100 |     requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any> && !std::is_same_v<T,empty>)
       | ^
 ../../../include/cpp2util.h:2137:59: note: in expansion of macro ‘CPP2_UFCS_’
- 2137 | 
+ 2137 |     { return std::any_cast<T>( x ); }
       |                                                           ^         
 mixed-bugfix-for-ufcs-non-local.cpp2:33:12: note: in expansion of macro ‘CPP2_UFCS_NONLOCAL’
 mixed-bugfix-for-ufcs-non-local.cpp2:33:36: error: template argument 1 is invalid
 ../../../include/cpp2util.h:2100:1: error: lambda-expression in template parameter type
- 2100 | constexpr auto is( X const& x ) -> bool
+ 2100 |     requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any> && !std::is_same_v<T,empty>)
       | ^
 ../../../include/cpp2util.h:2137:59: note: in expansion of macro ‘CPP2_UFCS_’
- 2137 | 
+ 2137 |     { return std::any_cast<T>( x ); }
       |                                                           ^         
 mixed-bugfix-for-ufcs-non-local.cpp2:21:12: note: in expansion of macro ‘CPP2_UFCS_NONLOCAL’
 mixed-bugfix-for-ufcs-non-local.cpp2:21:36: error: template argument 1 is invalid

regression-tests/test-results/gcc-14-c++2b/mixed-bugfix-for-ufcs-non-local.cpp.output

@@ -1,41 +1,41 @@
 In file included from mixed-bugfix-for-ufcs-non-local.cpp:6:
 ../../../include/cpp2util.h:2100:1: error: lambda-expression in template parameter type
- 2100 | constexpr auto is( X const& x ) -> bool
+ 2100 |     requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any> && !std::is_same_v<T,empty>)
       | ^
 ../../../include/cpp2util.h:2137:59: note: in expansion of macro ‘CPP2_UFCS_’
- 2137 | 
+ 2137 |     { return std::any_cast<T>( x ); }
       |                                                           ^         
 mixed-bugfix-for-ufcs-non-local.cpp2:13:12: note: in expansion of macro ‘CPP2_UFCS_NONLOCAL’
 mixed-bugfix-for-ufcs-non-local.cpp2:13:36: error: template argument 1 is invalid
 ../../../include/cpp2util.h:2100:1: error: lambda-expression in template parameter type
- 2100 | constexpr auto is( X const& x ) -> bool
+ 2100 |     requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any> && !std::is_same_v<T,empty>)
       | ^
 ../../../include/cpp2util.h:2137:59: note: in expansion of macro ‘CPP2_UFCS_’
- 2137 | 
+ 2137 |     { return std::any_cast<T>( x ); }
       |                                                           ^         
 mixed-bugfix-for-ufcs-non-local.cpp2:21:12: note: in expansion of macro ‘CPP2_UFCS_NONLOCAL’
 mixed-bugfix-for-ufcs-non-local.cpp2:21:36: error: template argument 1 is invalid
 ../../../include/cpp2util.h:2100:1: error: lambda-expression in template parameter type
- 2100 | constexpr auto is( X const& x ) -> bool
+ 2100 |     requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any> && !std::is_same_v<T,empty>)
       | ^
 ../../../include/cpp2util.h:2137:59: note: in expansion of macro ‘CPP2_UFCS_’
- 2137 | 
+ 2137 |     { return std::any_cast<T>( x ); }
       |                                                           ^         
 mixed-bugfix-for-ufcs-non-local.cpp2:31:12: note: in expansion of macro ‘CPP2_UFCS_NONLOCAL’
 mixed-bugfix-for-ufcs-non-local.cpp2:31:36: error: template argument 1 is invalid
 ../../../include/cpp2util.h:2100:1: error: lambda-expression in template parameter type
- 2100 | constexpr auto is( X const& x ) -> bool
+ 2100 |     requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any> && !std::is_same_v<T,empty>)
       | ^
 ../../../include/cpp2util.h:2137:59: note: in expansion of macro ‘CPP2_UFCS_’
- 2137 | 
+ 2137 |     { return std::any_cast<T>( x ); }
       |                                                           ^         
 mixed-bugfix-for-ufcs-non-local.cpp2:33:12: note: in expansion of macro ‘CPP2_UFCS_NONLOCAL’
 mixed-bugfix-for-ufcs-non-local.cpp2:33:36: error: template argument 1 is invalid
 ../../../include/cpp2util.h:2100:1: error: lambda-expression in template parameter type
- 2100 | constexpr auto is( X const& x ) -> bool
+ 2100 |     requires (std::is_same_v<X,std::any> && !std::is_same_v<T,std::any> && !std::is_same_v<T,empty>)
       | ^
 ../../../include/cpp2util.h:2137:59: note: in expansion of macro ‘CPP2_UFCS_’
- 2137 | 
+ 2137 |     { return std::any_cast<T>( x ); }
       |                                                           ^         
 mixed-bugfix-for-ufcs-non-local.cpp2:21:12: note: in expansion of macro ‘CPP2_UFCS_NONLOCAL’
 mixed-bugfix-for-ufcs-non-local.cpp2:21:36: error: template argument 1 is invalid

regression-tests/test-results/msvc-2022-c++20/pure2-assert-expected-not-null.cpp.output

@@ -6,7 +6,7 @@ pure2-assert-expected-not-null.cpp2(7): error C2143: syntax error: missing ';' b
 pure2-assert-expected-not-null.cpp2(7): error C2143: syntax error: missing ';' before '}'
 pure2-assert-expected-not-null.cpp2(9): error C2065: 'ex': undeclared identifier
 pure2-assert-expected-not-null.cpp2(9): error C2672: 'cpp2::impl::assert_not_null': no matching overloaded function found
-D:\a\cppfront\cppfront\include\cpp2util.h(855): note: could be 'decltype(auto) cpp2::impl::assert_not_null(_T0 &&,std::source_location)'
+D:\a\cppfront\cppfront\include\cpp2util.h(861): note: could be 'decltype(auto) cpp2::impl::assert_not_null(_T0 &&,std::source_location)'
 pure2-assert-expected-not-null.cpp2(14): error C2039: 'expected': is not a member of 'std'
 predefined C++ types (compiler internal)(347): note: see declaration of 'std'
 pure2-assert-expected-not-null.cpp2(14): error C2062: type 'int' unexpected
@@ -19,4 +19,4 @@ pure2-assert-expected-not-null.cpp2(14): note: while trying to match the argumen
 pure2-assert-expected-not-null.cpp2(14): error C2143: syntax error: missing ';' before '}'
 pure2-assert-expected-not-null.cpp2(15): error C2065: 'ex': undeclared identifier
 pure2-assert-expected-not-null.cpp2(15): error C2672: 'cpp2::impl::assert_not_null': no matching overloaded function found
-D:\a\cppfront\cppfront\include\cpp2util.h(855): note: could be 'decltype(auto) cpp2::impl::assert_not_null(_T0 &&,std::source_location)'
+D:\a\cppfront\cppfront\include\cpp2util.h(861): note: could be 'decltype(auto) cpp2::impl::assert_not_null(_T0 &&,std::source_location)'

regression-tests/test-results/msvc-2022-c++latest/pure2-regex_10_escapes.cpp.execution

@@ -9,26 +9,26 @@ Running tests_10_escapes:
 08_y: OK regex: foo(\h)bar parsed_regex: foo(\h)bar str: foo	bar result_expr: $1 expected_results 	
 09_y: OK regex: (\H)(\h) parsed_regex: (\H)(\h) str: foo	bar result_expr: $1-$2 expected_results o-	
 10_y: OK regex: (\h)(\H) parsed_regex: (\h)(\H) str: foo	bar result_expr: $1-$2 expected_results 	-b
-11_y: OK regex: foo(\v+)bar parsed_regex: foo(\v+)bar str: foo
+11_y: OK regex: foo(\v+)bar parsed_regex: foo(\v+)bar str: foo
+
 
+bar result_expr: $1 expected_results 
+
 
-bar result_expr: $1 expected_results 
 
+12_y: OK regex: (\V+)(\v) parsed_regex: (\V+)(\v) str: foo
+
 
+bar result_expr: $1-$2 expected_results foo-
+13_y: OK regex: (\v+)(\V) parsed_regex: (\v+)(\V) str: foo
+
 
-12_y: OK regex: (\V+)(\v) parsed_regex: (\V+)(\v) str: foo
-
-
-bar result_expr: $1-$2 expected_results foo-
-13_y: OK regex: (\v+)(\V) parsed_regex: (\v+)(\V) str: foo
-
-
-bar result_expr: $1-$2 expected_results 
-
+bar result_expr: $1-$2 expected_results 
+
 
 -b
-14_y: OK regex: foo(\v)bar parsed_regex: foo(\v)bar str: foobar result_expr: $1 expected_results 
-15_y: OK regex: (\V)(\v) parsed_regex: (\V)(\v) str: foobar result_expr: $1-$2 expected_results o-
+14_y: OK regex: foo(\v)bar parsed_regex: foo(\v)bar str: foobar result_expr: $1 expected_results 
+15_y: OK regex: (\V)(\v) parsed_regex: (\V)(\v) str: foobar result_expr: $1-$2 expected_results o-
 16_y: OK regex: (\v)(\V) parsed_regex: (\v)(\V) str: foobar result_expr: $1-$2 expected_results -b
 17_y: OK regex: foo\t\n\r\f\a\ebar parsed_regex: foo\t\n\r\f\a\ebar str: foo	
 bar result_expr: $& expected_results foo	

source/common.h

@@ -20,6 +20,15 @@
     #pragma GCC diagnostic ignored "-Wdangling-reference"
 #endif
 
+//  Disable some clang conversion warnings:
+//      cppfront uses signed integer types for indices and container sizes.
+//  Note: We don't pop the diagnostic because we want them disabled in the
+//  entire cppfront translation unit.
+#ifdef __clang__
+    #pragma clang diagnostic push
+    #pragma clang diagnostic ignored "-Wsign-conversion"
+#endif
+
 #include "cpp2util.h"
 
 
@@ -97,7 +106,7 @@ struct source_line
         break;case category::cpp1:          return "/* 1 */ ";
         break;case category::cpp2:          return "/* 2 */ ";
         break;case category::rawstring:     return "/* R */ ";
-        break;default: assert(!"illegal category"); abort();
+        break;default: assert(false && "ICE: illegal category"); abort();
         }
     }
 };

source/cppfront.cpp

@@ -113,10 +113,10 @@ auto main(
                     auto total = count.cpp1_lines + count.cpp2_lines;
                     auto total_lines = print_with_thousands(total);
                     out << "   Cpp1  "
-                        << std::right << std::setw(total_lines.size())
+                        << std::right << std::setw(unsafe_narrow<int>(total_lines.size()))
                         << print_with_thousands(count.cpp1_lines) << " line" << (count.cpp1_lines != 1 ? "s" : "");
                     out << "\n   Cpp2  "
-                        << std::right << std::setw(total_lines.size())
+                        << std::right << std::setw(unsafe_narrow<int>(total_lines.size()))
                         << print_with_thousands(count.cpp2_lines) << " line" << (count.cpp2_lines != 1 ? "s" : "");
                     if (total > 0) {
                         out << " (";
@@ -145,7 +145,7 @@ auto main(
                     for (auto [elapsed, name] : sorted_timers) {
                         std::cout
                             << "\n         "
-                            << std::right << std::setw(total_time.size())
+                            << std::right << std::setw(unsafe_narrow<int>(total_time.size()))
                             << print_with_thousands(elapsed) << " ms" << " in " << name;
                     }
                 }