Rollup merge of #67119 - RalfJung:miri-test-libstd, r=alexcrichton

libstd miri tests: avoid warnings

Ignore tests in a way that all the code still gets compiled, to get rid of all the "unused" warnings that otherwise show up when running the test suite in Miri.

7 files changed, 25 insertions, 18 deletions

diff --git a/src/libcore/tests/hash/mod.rs b/src/libcore/tests/hash/mod.rs
index 348245e24f6..ba0220f0d92 100644
--- a/src/libcore/tests/hash/mod.rs
+++ b/src/libcore/tests/hash/mod.rs
@@ -71,14 +71,16 @@ fn test_writer_hasher() {
     let ptr = 5_usize as *mut i32;
     assert_eq!(hash(&ptr), 5);
 
+    if cfg!(miri) { // Miri cannot hash pointers
+        return;
+    }
+
     let cs: &mut [u8] = &mut [1, 2, 3];
     let ptr = cs.as_ptr();
     let slice_ptr = cs as *const [u8];
-    #[cfg(not(miri))] // Miri cannot hash pointers
     assert_eq!(hash(&slice_ptr), hash(&ptr) + cs.len() as u64);
 
     let slice_ptr = cs as *mut [u8];
-    #[cfg(not(miri))] // Miri cannot hash pointers
     assert_eq!(hash(&slice_ptr), hash(&ptr) + cs.len() as u64);
 }
 
diff --git a/src/libcore/tests/num/dec2flt/mod.rs b/src/libcore/tests/num/dec2flt/mod.rs
index 4b772e12b6c..6bb348fd752 100644
--- a/src/libcore/tests/num/dec2flt/mod.rs
+++ b/src/libcore/tests/num/dec2flt/mod.rs
@@ -31,7 +31,11 @@ fn ordinary() {
     test_literal!(0.1);
     test_literal!(12345.);
     test_literal!(0.9999999);
-    #[cfg(not(miri))] // Miri is too slow
+
+    if cfg!(miri) { // Miri is too slow
+        return;
+    }
+
     test_literal!(2.2250738585072014e-308);
 }
 
@@ -53,7 +57,7 @@ fn large() {
 }
 
 #[test]
-#[cfg(not(miri))] // Miri is too slow
+#[cfg_attr(miri, ignore)] // Miri is too slow
 fn subnormals() {
     test_literal!(5e-324);
     test_literal!(91e-324);
@@ -65,7 +69,7 @@ fn subnormals() {
 }
 
 #[test]
-#[cfg(not(miri))] // Miri is too slow
+#[cfg_attr(miri, ignore)] // Miri is too slow
 fn infinity() {
     test_literal!(1e400);
     test_literal!(1e309);
@@ -77,9 +81,12 @@ fn infinity() {
 fn zero() {
     test_literal!(0.0);
     test_literal!(1e-325);
-    #[cfg(not(miri))] // Miri is too slow
+
+    if cfg!(miri) { // Miri is too slow
+        return;
+    }
+
     test_literal!(1e-326);
-    #[cfg(not(miri))] // Miri is too slow
     test_literal!(1e-500);
 }
 
diff --git a/src/libcore/tests/num/flt2dec/mod.rs b/src/libcore/tests/num/flt2dec/mod.rs
index f85369ce40b..2f94ea2fc4b 100644
--- a/src/libcore/tests/num/flt2dec/mod.rs
+++ b/src/libcore/tests/num/flt2dec/mod.rs
@@ -256,7 +256,6 @@ pub fn f32_shortest_sanity_test<F>(mut f: F) where F: FnMut(&Decoded, &mut [u8])
     check_shortest!(f(minf32) => b"1", -44);
 }
 
-#[cfg(not(miri))] // Miri is too slow
 pub fn f32_exact_sanity_test<F>(mut f: F)
         where F: FnMut(&Decoded, &mut [u8], i16) -> (usize, i16) {
     let minf32 = ldexp_f32(1.0, -149);
@@ -362,7 +361,6 @@ pub fn f64_shortest_sanity_test<F>(mut f: F) where F: FnMut(&Decoded, &mut [u8])
     check_shortest!(f(minf64) => b"5", -323);
 }
 
-#[cfg(not(miri))] // Miri is too slow
 pub fn f64_exact_sanity_test<F>(mut f: F)
         where F: FnMut(&Decoded, &mut [u8], i16) -> (usize, i16) {
     let minf64 = ldexp_f64(1.0, -1074);
diff --git a/src/libcore/tests/num/flt2dec/strategy/dragon.rs b/src/libcore/tests/num/flt2dec/strategy/dragon.rs
index 0c545b4d887..3d985c6796b 100644
--- a/src/libcore/tests/num/flt2dec/strategy/dragon.rs
+++ b/src/libcore/tests/num/flt2dec/strategy/dragon.rs
@@ -22,7 +22,7 @@ fn shortest_sanity_test() {
 }
 
 #[test]
-#[cfg(not(miri))] // Miri is too slow
+#[cfg_attr(miri, ignore)] // Miri is too slow
 fn exact_sanity_test() {
     // This test ends up running what I can only assume is some corner-ish case
     // of the `exp2` library function, defined in whatever C runtime we're
diff --git a/src/libcore/tests/num/flt2dec/strategy/grisu.rs b/src/libcore/tests/num/flt2dec/strategy/grisu.rs
index 13396646463..ff8373c6455 100644
--- a/src/libcore/tests/num/flt2dec/strategy/grisu.rs
+++ b/src/libcore/tests/num/flt2dec/strategy/grisu.rs
@@ -41,7 +41,7 @@ fn shortest_sanity_test() {
 }
 
 #[test]
-#[cfg(not(miri))] // Miri is too slow
+#[cfg_attr(miri, ignore)] // Miri is too slow
 fn exact_sanity_test() {
     // See comments in dragon.rs's exact_sanity_test for why this test is
     // ignored on MSVC
diff --git a/src/libcore/tests/ptr.rs b/src/libcore/tests/ptr.rs
index 4f5a9be579e..eea736bc88f 100644
--- a/src/libcore/tests/ptr.rs
+++ b/src/libcore/tests/ptr.rs
@@ -289,7 +289,7 @@ fn write_unaligned_drop() {
 }
 
 #[test]
-#[cfg(not(miri))] // Miri does not compute a maximal `mid` for `align_offset`
+#[cfg_attr(miri, ignore)] // Miri does not compute a maximal `mid` for `align_offset`
 fn align_offset_zst() {
     // For pointers of stride = 0, the pointer is already aligned or it cannot be aligned at
     // all, because no amount of elements will align the pointer.
@@ -304,7 +304,7 @@ fn align_offset_zst() {
 }
 
 #[test]
-#[cfg(not(miri))] // Miri does not compute a maximal `mid` for `align_offset`
+#[cfg_attr(miri, ignore)] // Miri does not compute a maximal `mid` for `align_offset`
 fn align_offset_stride1() {
     // For pointers of stride = 1, the pointer can always be aligned. The offset is equal to
     // number of bytes.
@@ -326,7 +326,7 @@ fn align_offset_stride1() {
 }
 
 #[test]
-#[cfg(not(miri))] // Miri is too slow
+#[cfg_attr(miri, ignore)] // Miri is too slow
 fn align_offset_weird_strides() {
     #[repr(packed)]
     struct A3(u16, u8);
diff --git a/src/libcore/tests/slice.rs b/src/libcore/tests/slice.rs
index eac18e93ab6..cc274b4aecf 100644
--- a/src/libcore/tests/slice.rs
+++ b/src/libcore/tests/slice.rs
@@ -1183,7 +1183,7 @@ fn test_rotate_right() {
 }
 
 #[test]
-#[cfg(not(miri))] // Miri is too slow
+#[cfg_attr(miri, ignore)] // Miri is too slow
 fn brute_force_rotate_test_0() {
     // In case of edge cases involving multiple algorithms
     let n = 300;
@@ -1302,7 +1302,7 @@ fn sort_unstable() {
 
 #[test]
 #[cfg(not(target_arch = "wasm32"))]
-#[cfg(not(miri))] // Miri is too slow
+#[cfg_attr(miri, ignore)] // Miri is too slow
 fn partition_at_index() {
     use core::cmp::Ordering::{Equal, Greater, Less};
     use rand::rngs::StdRng;
@@ -1505,7 +1505,7 @@ pub mod memchr {
 }
 
 #[test]
-#[cfg(not(miri))] // Miri does not compute a maximal `mid` for `align_offset`
+#[cfg_attr(miri, ignore)] // Miri does not compute a maximal `mid` for `align_offset`
 fn test_align_to_simple() {
     let bytes = [1u8, 2, 3, 4, 5, 6, 7];
     let (prefix, aligned, suffix) = unsafe { bytes.align_to::<u16>() };
@@ -1535,7 +1535,7 @@ fn test_align_to_zst() {
 }
 
 #[test]
-#[cfg(not(miri))] // Miri does not compute a maximal `mid` for `align_offset`
+#[cfg_attr(miri, ignore)] // Miri does not compute a maximal `mid` for `align_offset`
 fn test_align_to_non_trivial() {
     #[repr(align(8))]
     struct U64(u64, u64);