Fix a bunch of crashes discovered by fuzzing cppfront

include/cpp2util.h

@@ -561,7 +561,7 @@ class contract_group {
         std::cerr << ": " << msg;
     }
     std::cerr << "\n";
-    std::terminate();
+    std::exit(EXIT_FAILURE);
 }
 
 auto inline cpp2_default = contract_group(

regression-tests/mixed-bugfix-for-double-pound-else-error.cpp2

@@ -0,0 +1,2 @@
+#else
+#else

regression-tests/pure2-bugfix-for-assert-capture-error.cpp2

@@ -0,0 +1,3 @@
+crash_10: (foo: i32) = {
+  assert( 10LL as i32 == foo$);
+}

regression-tests/pure2-bugfix-for-bad-capture-error.cpp2

@@ -0,0 +1,3 @@
+crash_10: (foo: i32) = {
+  assert( 10LL as i32 == foo$);
+}

regression-tests/pure2-bugfix-for-bad-decltype-error.cpp2

@@ -0,0 +1,4 @@
+crash_89: () = {
+    f := new<int>(0);
+    _ = f is decltype.f); 
+}

regression-tests/pure2-bugfix-for-bad-parameter-error.cpp2

@@ -0,0 +1 @@
+print: <T: type> (inout out: std::ostream=args: T) requires true = {}

regression-tests/pure2-bugfix-for-functions-before-superclasses-error.cpp2

@@ -0,0 +1,8 @@
+crash_m0b: type = {
+}
+
+crash_m0c: type = {
+  name: i32;
+  get_name: (this) -> i32 = { return name; }
+  this: crash_m0b;
+}

regression-tests/pure2-bugfix-for-invalid-alias-error.cpp2

@@ -0,0 +1,3 @@
+outer: type = {
+    x: requires true == 42;
+}

regression-tests/pure2-bugfix-for-late-comments.cpp2

@@ -0,0 +1,11 @@
+
+main: () -> int = {
+  x := crash_m0();
+  _ = x;
+}
+
+crash_m0: type = {
+  operator-: (this, _) -> int = 0;/* Comment starts here
+And continues here
+*/
+}

regression-tests/pure2-bugfix-for-naked-unsigned-char-error.cpp2

@@ -0,0 +1,3 @@
+main: () = {
+    e: unsigned char
+}

regression-tests/pure2-bugfix-for-namespace-error.cpp2

@@ -0,0 +1,9 @@
+crash_96: @print type = {
+    namespace_alias: namespace = type_alias: type == array<int,10>;
+}
+
+crash_96a: @print type = {
+    test: () = {
+        namespace_alias: namespace = type_alias: type == array<int,10>;
+    }
+}

regression-tests/test-results/clang-12-c++20/pure2-expected-is-as.cpp.output

@@ -80,56 +80,56 @@ In file included from pure2-expected-is-as.cpp:7:
 ../../../include/cpp2util.h:469:72: error: invalid application of 'sizeof' to a function type
     (std::is_floating_point_v<From> && std::is_floating_point_v<To> && sizeof(From) > sizeof(To)) || // NOLINT(misc-redundant-expression)
                                                                        ^~~~~~~~~~~~
-../../../include/cpp2util.h:2923:19: note: in instantiation of variable template specialization 'cpp2::impl::is_narrowing_v' requested here
+../../../include/cpp2util.h:2924:19: note: in instantiation of variable template specialization 'cpp2::impl::is_narrowing_v' requested here
     if constexpr (is_narrowing_v<C, CPP2_TYPEOF(x)>) {
                   ^
 pure2-expected-is-as.cpp2:39:28: note: in instantiation of function template specialization 'cpp2::impl::as_<int, double (&)(double) noexcept>' requested here
     auto val1 {cpp2::impl::as_<int>(ex1)}; 
                            ^
 In file included from pure2-expected-is-as.cpp:7:
-../../../include/cpp2util.h:2943:12: error: no matching function for call to 'as'
+../../../include/cpp2util.h:2944:12: error: no matching function for call to 'as'
     return as<C>(CPP2_FORWARD(x));
            ^~~~~
 pure2-expected-is-as.cpp2:39:28: note: in instantiation of function template specialization 'cpp2::impl::as_<int, double (&)(double) noexcept>' requested here
     auto val1 {cpp2::impl::as_<int>(ex1)}; 
                            ^
-../../../include/cpp2util.h:1901:16: note: candidate template ignored: constraints not satisfied [with C = int, x:auto = double (&)(double) noexcept]
+../../../include/cpp2util.h:1902:16: note: candidate template ignored: constraints not satisfied [with C = int, x:auto = double (&)(double) noexcept]
 constexpr auto as(auto&& x CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAULT_AS) -> decltype(auto)
                ^
-../../../include/cpp2util.h:1907:18: note: because 'std::is_scalar_v<std::remove_cvref_t<decltype(x)> >' evaluated to false
+../../../include/cpp2util.h:1908:18: note: because 'std::is_scalar_v<std::remove_cvref_t<decltype(x)> >' evaluated to false
                 (std::is_scalar_v<CPP2_TYPEOF(x)> && !std::is_enum_v<CPP2_TYPEOF(x)>)
                  ^
-../../../include/cpp2util.h:1908:17: note: and 'std::is_floating_point_v<std::remove_cvref_t<decltype(x)> >' evaluated to false
+../../../include/cpp2util.h:1909:17: note: and 'std::is_floating_point_v<std::remove_cvref_t<decltype(x)> >' evaluated to false
             ||  std::is_floating_point_v<CPP2_TYPEOF(x)>
                 ^
-../../../include/cpp2util.h:1909:17: note: and 'std::is_base_of_v<int, std::remove_cvref_t<decltype(x)> >' evaluated to false
+../../../include/cpp2util.h:1910:17: note: and 'std::is_base_of_v<int, std::remove_cvref_t<decltype(x)> >' evaluated to false
             ||  std::is_base_of_v<C, CPP2_TYPEOF(x)>
                 ^
-../../../include/cpp2util.h:1910:17: note: and 'std::is_base_of_v<std::remove_cvref_t<decltype(x)>, int>' evaluated to false
+../../../include/cpp2util.h:1911:17: note: and 'std::is_base_of_v<std::remove_cvref_t<decltype(x)>, int>' evaluated to false
             ||  std::is_base_of_v<CPP2_TYPEOF(x), C>
                 ^
-../../../include/cpp2util.h:1911:30: note: and 'C({std::forward<decltype(x)>(x)})' would be invalid: cannot initialize a value of type 'int' with an lvalue of type 'double (double) noexcept'
+../../../include/cpp2util.h:1912:30: note: and 'C({std::forward<decltype(x)>(x)})' would be invalid: cannot initialize a value of type 'int' with an lvalue of type 'double (double) noexcept'
             ||  requires { C{CPP2_FORWARD(x)}; }
                              ^
 ../../../include/cpp2util.h:327:37: note: expanded from macro 'CPP2_FORWARD'
 #define CPP2_FORWARD(x)             std::forward<decltype(x)>(x)
                                     ^
-../../../include/cpp2util.h:2040:6: note: candidate template ignored: constraints not satisfied [with C = int, X = double (&)(double) noexcept]
+../../../include/cpp2util.h:2041:6: note: candidate template ignored: constraints not satisfied [with C = int, X = double (&)(double) noexcept]
 auto as(X&& x CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAULT_AS) -> decltype(auto)
      ^
-../../../include/cpp2util.h:2039:23: note: because 'specialization_of_template<double (&)(double) noexcept, std::variant>' evaluated to false
+../../../include/cpp2util.h:2040:23: note: because 'specialization_of_template<double (&)(double) noexcept, std::variant>' evaluated to false
 template< typename C, specialization_of_template<std::variant> X >
                       ^
-../../../include/cpp2util.h:891:7: note: because 'specialization_of_template_helper<C>(std::forward<X>(x))' would be invalid: no matching function for call to 'specialization_of_template_helper'
+../../../include/cpp2util.h:892:7: note: because 'specialization_of_template_helper<C>(std::forward<X>(x))' would be invalid: no matching function for call to 'specialization_of_template_helper'
     { specialization_of_template_helper<C>(std::forward<X>(x)) } -> std::same_as<std::true_type>;
       ^
-../../../include/cpp2util.h:2087:16: note: candidate template ignored: constraints not satisfied [with T = int, X = double (&)(double) noexcept]
+../../../include/cpp2util.h:2088:16: note: candidate template ignored: constraints not satisfied [with T = int, X = double (&)(double) noexcept]
 constexpr auto as( X && x ) -> decltype(auto) {
                ^
-../../../include/cpp2util.h:2086:22: note: because 'same_type_as<double (&)(double) noexcept, std::any>' evaluated to false
+../../../include/cpp2util.h:2087:22: note: because 'same_type_as<double (&)(double) noexcept, std::any>' evaluated to false
 template<typename T, same_type_as<std::any> X>
                      ^
-../../../include/cpp2util.h:921:29: note: because 'std::same_as<std::remove_cvref_t<double (&)(double) noexcept>, std::remove_cvref_t<any> >' evaluated to false
+../../../include/cpp2util.h:922:29: note: because 'std::same_as<std::remove_cvref_t<double (&)(double) noexcept>, std::remove_cvref_t<any> >' evaluated to false
 concept same_type_as = std::same_as<std::remove_cvref_t<X>, std::remove_cvref_t<C>>;
                             ^
 /usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/concepts:63:19: note: because '__detail::__same_as<double (double) noexcept, std::any>' evaluated to false
@@ -138,19 +138,19 @@ concept same_type_as = std::same_as<std::remove_cvref_t<X>, std::remove_cvref_t<
 /usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/concepts:57:27: note: because 'std::is_same_v<double (double) noexcept, std::any>' evaluated to false
       concept __same_as = std::is_same_v<_Tp, _Up>;
                           ^
-../../../include/cpp2util.h:2130:16: note: candidate template ignored: constraints not satisfied [with T = int, X = double (&)(double) noexcept]
+../../../include/cpp2util.h:2131:16: note: candidate template ignored: constraints not satisfied [with T = int, X = double (&)(double) noexcept]
 constexpr auto as( X&& x ) -> decltype(auto) { 
                ^
-../../../include/cpp2util.h:2129:22: note: because 'specialization_of_template<double (&)(double) noexcept, std::optional>' evaluated to false
+../../../include/cpp2util.h:2130:22: note: because 'specialization_of_template<double (&)(double) noexcept, std::optional>' evaluated to false
 template<typename T, specialization_of_template<std::optional> X>
                      ^
-../../../include/cpp2util.h:891:7: note: because 'specialization_of_template_helper<C>(std::forward<X>(x))' would be invalid: no matching function for call to 'specialization_of_template_helper'
+../../../include/cpp2util.h:892:7: note: because 'specialization_of_template_helper<C>(std::forward<X>(x))' would be invalid: no matching function for call to 'specialization_of_template_helper'
     { specialization_of_template_helper<C>(std::forward<X>(x)) } -> std::same_as<std::true_type>;
       ^
-../../../include/cpp2util.h:1876:16: note: candidate function template not viable: requires 0 arguments, but 1 was provided
+../../../include/cpp2util.h:1877:16: note: candidate function template not viable: requires 0 arguments, but 1 was provided
 constexpr auto as() -> auto
                ^
-../../../include/cpp2util.h:1887:16: note: candidate function template not viable: requires 0 arguments, but 1 was provided
+../../../include/cpp2util.h:1888:16: note: candidate function template not viable: requires 0 arguments, but 1 was provided
 constexpr auto as() -> auto
                ^
 pure2-expected-is-as.cpp2:39:37: error: use of undeclared identifier 'ex1'

regression-tests/test-results/mixed-bugfix-for-double-pound-else-error.cpp2.output

@@ -0,0 +1,5 @@
+mixed-bugfix-for-double-pound-else-error.cpp2...
+mixed-bugfix-for-double-pound-else-error.cpp2(2,1): error: #else does not match a prior #if
+mixed-bugfix-for-double-pound-else-error.cpp2(3,1): error: #else does not match a prior #if
+mixed-bugfix-for-double-pound-else-error.cpp2(3,1): error: #else already encountered for this #if
+

regression-tests/test-results/msvc-2022-c++latest/pure2-bugfix-for-late-comments.cpp.output

@@ -0,0 +1 @@
+pure2-bugfix-for-late-comments.cpp

regression-tests/test-results/pure2-bugfix-for-assert-capture-error.cpp2.output

@@ -0,0 +1,4 @@
+pure2-bugfix-for-assert-capture-error.cpp2...
+pure2-bugfix-for-assert-capture-error.cpp2(2,29): error: $ (capture) cannot appear here - it must appear in an anonymous expression function, a postcondition, or an interpolated string literal (at '$')
+pure2-bugfix-for-assert-capture-error.cpp2(2,23): error: expected ')' at the end of the contract (at '==')
+

regression-tests/test-results/pure2-bugfix-for-bad-capture-error.cpp2.output

@@ -0,0 +1,4 @@
+pure2-bugfix-for-bad-capture-error.cpp2...
+pure2-bugfix-for-bad-capture-error.cpp2(2,29): error: $ (capture) cannot appear here - it must appear in an anonymous expression function, a postcondition, or an interpolated string literal (at '$')
+pure2-bugfix-for-bad-capture-error.cpp2(2,23): error: expected ')' at the end of the contract (at '==')
+

regression-tests/test-results/pure2-bugfix-for-bad-decltype-error.cpp2.output

@@ -0,0 +1,6 @@
+pure2-bugfix-for-bad-decltype-error.cpp2...
+pure2-bugfix-for-bad-decltype-error.cpp2(3,14): error: 'decltype' must be followed by a single parenthesized expression
+pure2-bugfix-for-bad-decltype-error.cpp2(3,24): error: 'is' must be followed by a type-id or an expression
+pure2-bugfix-for-bad-decltype-error.cpp2(3,14): error: 'decltype' must be followed by a single parenthesized expression
+pure2-bugfix-for-bad-decltype-error.cpp2(3,24): error: 'is' must be followed by a type-id or an expression
+

regression-tests/test-results/pure2-bugfix-for-bad-parameter-error.cpp2.output

@@ -0,0 +1,3 @@
+pure2-bugfix-for-bad-parameter-error.cpp2...
+pure2-bugfix-for-bad-parameter-error.cpp2(1,50): error: parameter must be initialized with an expression (at ')')
+

regression-tests/test-results/pure2-bugfix-for-functions-before-superclasses-error.cpp2.output

@@ -0,0 +1,3 @@
+pure2-bugfix-for-functions-before-superclasses-error.cpp2...
+pure2-bugfix-for-functions-before-superclasses-error.cpp2(7,3): error: a type cannot declare a parent after defining a function
+

regression-tests/test-results/pure2-bugfix-for-invalid-alias-error.cpp2.output

@@ -0,0 +1,3 @@
+pure2-bugfix-for-invalid-alias-error.cpp2...
+pure2-bugfix-for-invalid-alias-error.cpp2(2,25): error: invalid alias declaration - expected 'type', 'namespace', or a type-id after ':'
+

regression-tests/test-results/pure2-bugfix-for-late-comments.cpp

@@ -0,0 +1,47 @@
+
+#define CPP2_IMPORT_STD          Yes
+
+//=== Cpp2 type declarations ====================================================
+
+
+#include "cpp2util.h"
+
+#line 1 "pure2-bugfix-for-late-comments.cpp2"
+
+#line 7 "pure2-bugfix-for-late-comments.cpp2"
+class crash_m0;
+
+
+//=== Cpp2 type definitions and function declarations ===========================
+
+#line 1 "pure2-bugfix-for-late-comments.cpp2"
+
+#line 2 "pure2-bugfix-for-late-comments.cpp2"
+[[nodiscard]] auto main() -> int;
+
+#line 7 "pure2-bugfix-for-late-comments.cpp2"
+class crash_m0 {
+  public: [[nodiscard]] auto operator-([[maybe_unused]] auto const& unnamed_param_2) const& -> int;
+  public: crash_m0() = default;
+  public: crash_m0(crash_m0 const&) = delete; /* No 'that' constructor, suppress copy */
+  public: auto operator=(crash_m0 const&) -> void = delete;
+
+
+#line 11 "pure2-bugfix-for-late-comments.cpp2"
+};
+
+
+//=== Cpp2 function definitions =================================================
+
+#line 1 "pure2-bugfix-for-late-comments.cpp2"
+
+#line 2 "pure2-bugfix-for-late-comments.cpp2"
+[[nodiscard]] auto main() -> int{
+  auto x {crash_m0()}; 
+  static_cast<void>(cpp2::move(x));
+}
+
+#line 8 "pure2-bugfix-for-late-comments.cpp2"
+  [[nodiscard]] auto crash_m0::operator-([[maybe_unused]] auto const& unnamed_param_2) const& -> int { return 0;  }/* Comment starts here
+And continues here
+*/

regression-tests/test-results/pure2-bugfix-for-late-comments.cpp2.output

@@ -0,0 +1,2 @@
+pure2-bugfix-for-late-comments.cpp2... ok (all Cpp2, passes safety checks)
+

regression-tests/test-results/pure2-bugfix-for-naked-unsigned-char-error.cpp2.output

@@ -0,0 +1,8 @@
+pure2-bugfix-for-naked-unsigned-char-error.cpp2...
+pure2-bugfix-for-naked-unsigned-char-error.cpp2(2,8): error: 'unsigned char' - did you mean 'u8' (usually best) or 'cpp2::_uchar'?
+pure2-bugfix-for-naked-unsigned-char-error.cpp2(2,8): error: 'unsigned char' is an old-style C/C++ multi-word keyword type
+    - most such types should be used only for interoperability with older code
+    - using those when you need them is fine, but name them with these short names instead:
+        short, ushort, int, uint, long, ulong, longlong, ulonglong, longdouble, _schar, _uchar
+    - see also cpp2util.h > "Convenience names for integer types"
+

regression-tests/test-results/pure2-bugfix-for-namespace-error.cpp2.output

@@ -0,0 +1,3 @@
+pure2-bugfix-for-namespace-error.cpp2...
+pure2-bugfix-for-namespace-error.cpp2(2,22): error: types cannot contain namespaces (at 'namespace')
+

source/io.h

@@ -362,9 +362,12 @@ class braces_tracker
             else             { --else_net_braces; }
         }
 
-        auto found_preprocessor_else() -> void {
-            assert (!found_else);
+        auto found_preprocessor_else_was_there_another() -> bool {
+            if (found_else) {
+                return true; 
+            }
             found_else = true;
+            return false;
         }
 
         //  If the "if" and "else" branches opened/closed the same net number
@@ -469,7 +472,14 @@ class braces_tracker
             );
         }
 
-        preprocessor.back().found_preprocessor_else();
+        if (preprocessor.back().found_preprocessor_else_was_there_another()) {
+            //  If this is the second or subsequent #else, it doesn't match
+            //  the prior #if, so report an error
+            errors.emplace_back(
+                lineno,
+                "#else already encountered for this #if"
+            );
+        };
     }
 
     //  Exiting an #endif

source/lex.h

@@ -713,13 +713,19 @@ auto lex_line(
             tokens.pop_back();
             ++num_merged_tokens;
         }
-
-        tokens.push_back({
-            &generated_text.back()[0],
-            std::ssize(generated_text.back()),
-            pos,
-            lexeme::Keyword
-            });
+
+        // It's an error to have more than one of these, but we require that
+        // the number of tokens has not gone down. So just push back as many
+        // tokens as we merged. This will ensure that the token count remains
+        // the same. 
+        for (auto i = 0; i < num_merged_tokens; i++) {
+            tokens.push_back({
+                &generated_text.back()[0],
+                std::ssize(generated_text.back()),
+                pos,
+                lexeme::Keyword
+                });
+        }
 
         if (num_merged_tokens > 1)
         {
@@ -750,8 +756,6 @@ auto lex_line(
                 "        short, ushort, int, uint, long, ulong, longlong, ulonglong, longdouble, _schar, _uchar\n"
                 "    - see also cpp2util.h > \"Convenience names for integer types\""
             );
-
-            return;
         }
 
         tokens.push_back(last_token);