Crate qed

Compile time assertions.

This crate contains compile time assertion macros used for maintaining safety invariants or limiting platform support. If the assertion is false, a compiler error is emitted.

Examples

qed::const_assert!(usize::BITS >= u32::BITS);
qed::const_assert_eq!("Veni, vidi, vici".len(), 16);
qed::const_assert_ne!('∎'.len_utf8(), 1);
qed::const_assert_matches!(NonZeroU8::new(42), Some(nz) if nz.get() == 42);

Assertion failures will result in a compile error:

qed::const_assert!("non-empty string".is_empty());

Macros

const_assert

Asserts that a boolean expression is true at compile time.

const_assert_bytes_has_no_nul

Asserts that a byte slice does not contain any NUL (\0) bytes.

const_assert_eq

Asserts that two expressions are equal to each other (using PartialEq) at compile time.

const_assert_matches

Asserts that an expression matches any of the given patterns at compile time.

const_assert_ne

Asserts that two expressions are not equal to each other (using PartialEq) at compile time.

const_assert_size_eq

Asserts that two types have the same size at compile time.

const_cstr_from_bytes

Construct a const CStr from the given bytes at compile time and assert that the given bytes are a valid CStr (NUL terminated with no interior NUL bytes).

const_cstr_from_str

Construct a const CStr from the given str at compile time and assert that the given str bytes are a valid CStr (NUL terminated with no interior NUL bytes).

lossless_cast_u32_to_usize

Cast a u32 to usize at runtime with a compile time assert that the cast is lossless and will not overflow.