Add workaround for rust-lang/rust#52478.

Author: AltSysrq

.travis.yml

@@ -17,6 +17,7 @@ script:
   - |
       (cd proptest && travis-cargo build) &&
       (cd proptest && travis-cargo test) &&
+      (cd proptest && env RUST_FLAGS='-C link-dead-code' travis-cargo --only stable build -- --no-default-features --features default-code-coverage) &&
       (cd proptest && travis-cargo --only stable build -- --no-default-features --features fork) &&
       (cd proptest && travis-cargo --only stable build -- --lib --no-default-features --features std) &&
       (cd proptest && travis-cargo --only nightly build -- --no-default-features --features "alloc unstable") &&

proptest/CHANGELOG.md

@@ -30,6 +30,11 @@ makes it possible to use an external source of entropy with Proptest.
 - `TestRunner` now has a `deterministic()` constructor which uses the same RNG
   every time, to facilitate doing statistical tests on strategy outputs.
 
+- There is now a work-around for a [compiler
+  bug](https://github.com/rust-lang/rust/issues/52478) which prevents building
+  with `-C link-dead-code`. Please see this issue for details:
+  https://github.com/AltSysrq/proptest/issues/124
+
 ### Deprecations
 
 - The `load_persisted_failures` and `save_persisted_failure` methods on the

proptest/Cargo.toml

@@ -25,7 +25,9 @@ service = "github"
 
 [features]
 
-default = ["std", "fork", "timeout", "bit-set"]
+default = ["std", "fork", "timeout", "bit-set", "break-dead-code"]
+# Everything in `default` that doesn't break code coverage builds
+default-code-coverage = ["std", "fork", "timeout", "bit-set"]
 
 # Enables unstable features of Rust.
 unstable = []
@@ -53,6 +55,10 @@ timeout = ["fork", "rusty-fork/timeout"]
 # need it excluded, however.
 atomic64bit = []
 
+# Include features which break the Rust compiler when `-C link-dead-code` is
+# passed (see https://github.com/AltSysrq/proptest/issues/124).
+break-dead-code = []
+
 [dependencies]
 bitflags = "1.0.1"
 

proptest/src/arbitrary/_alloc/char.rs

@@ -43,6 +43,7 @@ impl_wrap_char!(ToLowercase, char::to_lowercase);
 #[cfg(feature = "unstable")]
 impl_wrap_char!(ToUppercase, char::to_uppercase);
 
+#[cfg(feature = "break-dead-code")]
 arbitrary!(DecodeUtf16<<Vec<u16> as IntoIterator>::IntoIter>,
     SMapped<Vec<u16>, Self>;
     static_map(vec(any::<u16>(), ..VEC_MAX), decode_utf16)
@@ -71,10 +72,14 @@ mod test {
         escape_default => EscapeDefault,
         escape_unicode => EscapeUnicode,
         parse_char_error => ParseCharError,
-        decode_utf16 => DecodeUtf16<<Vec<u16> as IntoIterator>::IntoIter>,
         decode_utf16_error => DecodeUtf16Error
     );
 
+    #[cfg(feature = "break-dead-code")]
+    no_panic_test!(
+        decode_utf16 => DecodeUtf16<<Vec<u16> as IntoIterator>::IntoIter>
+    );
+
     #[cfg(feature = "unstable")]
     no_panic_test!(
         to_lowercase => ToLowercase,