rust-lang/rust · error

ptr_sized_integer: unknown pointer bit size {bits}

Error message

ptr_sized_integer: unknown pointer bit size {bits}

What it means

ptr_sized_integer maps the default pointer width to the matching codegen Integer (I16/I32/I64), used for ptrtoint/inttoptr and size_t-like temporaries. Widths outside 16/32/64 are unsupported and panic, since there is no wider StandardInteger to represent them.

Source

Thrown at compiler/rustc_abi/src/lib.rs:685

    /// so we adopt such a more-constrained size bound due to its technical limitations.
    #[inline]
    pub fn obj_size_bound_in(&self, address_space: AddressSpace) -> u64 {
        match self.pointer_size_in(address_space).bits() {
            16 => 1 << 15,
            32 => 1 << 31,
            64 => 1 << 61,
            bits => panic!("obj_size_bound: unknown pointer bit size {bits}"),
        }
    }

    #[inline]
    pub fn ptr_sized_integer(&self) -> Integer {
        use Integer::*;
        match self.pointer_offset().bits() {
            16 => I16,
            32 => I32,
            64 => I64,
            bits => panic!("ptr_sized_integer: unknown pointer bit size {bits}"),
        }
    }

    #[inline]
    pub fn ptr_sized_integer_in(&self, address_space: AddressSpace) -> Integer {
        use Integer::*;
        match self.pointer_offset_in(address_space).bits() {
            16 => I16,
            32 => I32,
            64 => I64,
            bits => panic!("ptr_sized_integer: unknown pointer bit size {bits}"),
        }
    }

    /// psABI-mandated alignment for a vector type, if any
    #[inline]
    fn c_vector_align(&self, vec_size: Size) -> Option<Align> {
        self.vector_align

View on GitHub (pinned to 22057b88b0)

Solutions

1. Check the target's pointer_width and data-layout 'p:size:align' token via rustc --print target-spec-json.
2. If the width is intentional, extend the match in ptr_sized_integer and ptr_sized_integer_in (and add a matching Integer variant if needed).
3. Fix the malformed target spec that produced the unsupported width.

Example fix

// before
match self.pointer_offset().bits() {
    16 => I16,
    32 => I32,
    64 => I64,
    bits => panic!("ptr_sized_integer: unknown pointer bit size {bits}"),
}

// after: add the missing width (requires an I128 variant / codegen support)
match self.pointer_offset().bits() {
    16 => I16,
    32 => I32,
    64 => I64,
    128 => I128,
    bits => panic!("ptr_sized_integer: unknown pointer bit size {bits}"),
}

// ptr_sized_integer() panics on pointer_offset bits outside {16,32,64}.
use rustc_abi::TargetDataLayout;

fn check_ptr_sized_integer(dl: &TargetDataLayout) -> Result<(), String> {
    match dl.pointer_offset().bits() {
        16 | 32 | 64 => Ok(()),
        bits => Err(format!("ptr_sized_integer: unsupported pointer bit size {bits}")),
    }
}

check_ptr_sized_integer(&dl)?;
let int = dl.ptr_sized_integer();

// Predicate: does this layout have a supported pointer-sized integer?
fn has_ptr_sized_integer(dl: &rustc_abi::TargetDataLayout) -> bool {
    matches!(dl.pointer_offset().bits(), 16 | 32 | 64)
}

When it happens

Trigger: Calling ptr_sized_integer() on a TargetDataLayout whose pointer_offset (derived from pointer_size) is not 16/32/64 bits — e.g. an experimental 128-bit-pointer target or a malformed data-layout 'p' token.

Common situations: Experimental targets (CHERI, research ISAs), hand-built layouts in miri/cg_clif, or a target spec typo producing an odd pointer width during codegen of pointer-sized integers (usize/isize).

Related errors

• obj_size_bound: unknown pointer bit size {bits}
• unsupported integer: {self:?}
• unsupported float: {self:?}
• Use of unknown address space {c:?}
• `homogeneous_aggregate` should not be called for scalable ve

AI-assisted analysis of rust-lang/rust@22057b88b0 (2026-08-03). Data as JSON: /data/errors/fe64066683565374.json. Report an issue: GitHub.