ICE: invalid abi for platform should have reported an error: "efiapi"

[pmur]

Code

I think a cherry-pick into 1.89.0 (7e0eb3b) produces a valid ICE error message due to calling a function with an unsupported abi. Though, the place where the expected error should be generated is only a warning in 1.89. I think the warning will be an error in 1.90.

# Setup rust 1.89.0
git clone https://github.com/rust-osdev/uefi-rs.git
cd uefi-rs/uefi
cargo build

Generates warnings like:

warning: the calling convention "efiapi" is not supported on this target
  --> uefi-raw/src/protocol/acpi.rs:9:29
   |
9  |       pub install_acpi_table: unsafe extern "efiapi" fn(
   |  _____________________________^
10 | |         this: *const Self,
11 | |         acpi_table_buffer: *const c_void,
12 | |         acpi_table_size: usize,
13 | |         table_key: *mut usize,
14 | |     ) -> Status,
   | |_______________^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #130260 <https://github.com/rust-lang/rust/issues/130260>
   = note: `#[warn(unsupported_fn_ptr_calling_conventions)]` on by default

And if the function is called, generates an ICE:

error: internal compiler error: invalid abi for platform should have reported an error: "efiapi"
  --> uefi/src/proto/acpi.rs:53:13
   |
53 |             (self.0.install_acpi_table)(&self.0, acpi_table_ptr, acpi_table_size, &mut table_key)
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |

And a simplified reproducer:

pub struct Foo {
        x: extern "efiapi" fn(),
}

pub fn foo_func(f: Foo) {
        (f.x)();
}

Meta

rustc --version --verbose:

rustc 1.89.0 (29483883e 2025-08-04)
binary: rustc
commit-hash: 29483883eed69d5fb4db01964cdf2af4d86e9cb2
commit-date: 2025-08-04
host: powerpc64le-unknown-linux-gnu
release: 1.89.0
LLVM version: 20.1.7

Error output

note: delayed at compiler/rustc_hir_typeck/src/callee.rs:162:39 - disabled backtrace
   --> uefi/src/proto/pci/root_bridge.rs:127:13
    |
127 | /             (self.io_access.read)(
128 | |                 self.proto,
129 | |                 width_mode,
130 | |                 addr.into(),
131 | |                 data.len(),
132 | |                 data.as_mut_ptr().cast(),
133 | |             )
    | |_____________^

error: internal compiler error: invalid abi for platform should have reported an error: "efiapi"
   --> uefi/src/proto/pci/root_bridge.rs:150:13
    |
150 | /             (self.io_access.write)(
151 | |                 self.proto,
152 | |                 width_mode,
153 | |                 addr.into(),
154 | |                 data.len(),
155 | |                 data.as_ptr().cast(),
156 | |             )
    | |_____________^
    |

[apiraino]

Assigning priority (discussion on Zulip).

@rustbot label -I-prioritize +P-medium

[compiler-errors]

This is a hard error in 1.90, so I'd say it's medium priority. I don't think it's worth fixing, but could be fixed by removing the delayed span bug.