Allow emission of i64::MIN integer literal (rust-lang#369)

Changelog.md

@@ -16,6 +16,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed
 - Convert `float` and `double` to `f32` and `f64` by default (#348).
 
+### Fixed
+- Allow emission of -9223372036854775808 integer literal (#375)
+
 ## [0.18.0] - 2016-06-05
 ### Breaking
 - New command line interface.

src/gen.rs

@@ -954,9 +954,17 @@ fn cunion_to_rs(ctx: &mut GenCtx,
     items
 }
 
+fn i64_abs(i: i64) -> u64 {
+    if i<0 {
+        i.wrapping_neg() as u64
+    } else {
+        i as u64
+    }
+}
+
 /// Converts a signed number to AST Expression.
 fn i64_to_int_lit(ctx: &mut GenCtx, value: i64) -> P<ast::Expr> {
-    let int_lit = ast::LitKind::Int(value.abs() as u64, ast::LitIntType::Unsuffixed);
+    let int_lit = ast::LitKind::Int(i64_abs(value), ast::LitIntType::Unsuffixed);
     let expr = ctx.ext_cx.expr_lit(ctx.span, int_lit);
     if value < 0 {
         let negated = ast::ExprKind::Unary(ast::UnOp::Neg, expr);

tests/headers/enum_explicit_type.hpp

@@ -20,3 +20,7 @@ enum MuchLong: long {
 enum MuchLongLong: unsigned long long {
     MuchHigh = 4294967296,
 };
+
+enum MostLongLong: long long {
+    MostLow = -9223372036854775808,
+};

tests/test_enum.rs

@@ -95,6 +95,10 @@ fn with_explicitly_typed_cxx_enum() {
         #[repr(u64)]
         #[derive(Debug)]
         pub enum MuchLongLong { MuchHigh = 4294967296, }
+        #[derive(Copy, Clone)]
+        #[repr(i64)]
+        #[derive(Debug)]
+        pub enum MostLongLong { MostLow = -9223372036854775808, }
     ");
     assert_bind_eq(default_without_rust_enums(), "headers/enum_explicit_type.hpp", "
         pub type Foo = u8;
@@ -110,6 +114,8 @@ fn with_explicitly_typed_cxx_enum() {
         pub const MuchLow: MuchLong = -4294967296;
         pub type MuchLongLong = u64;
         pub const MuchHigh: MuchLongLong = 4294967296;
+        pub type MostLongLong = i64;
+        pub const MostLow: MostLongLong = -9223372036854775808;
     ");
 }