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Error out when repr(align) exceeds COFF limit
The PE-COFF binary format limits section alignment to 8192 bytes. Emit error when alignment exceeds this limit to avoid crash in llvm.
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-19
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8 files changed

+221
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‎compiler/rustc_error_codes/src/error_codes/E0806.md

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The value of `N` that was specified for `repr(align(N))` was greater than the
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PE-COFF limit (8192 bytes).
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Erroneous code example:
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```compile_fail,E0806
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#[repr(align(16384))] // error: alignment must not be greater than 8192 bytes
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// for COFF targets
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enum Foo {
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Bar(u64),
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}
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```

‎compiler/rustc_error_codes/src/lib.rs

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@@ -548,6 +548,7 @@ E0802: 0802,
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E0803: 0803,
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E0804: 0804,
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E0805: 0805,
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E0806: 0806,
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);
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)
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}

‎compiler/rustc_passes/messages.ftl

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@@ -583,6 +583,9 @@ passes_remove_fields =
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*[other] fields
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}
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passes_repr_align_greater_than_coff_max =
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alignment must not be greater than 8192 bytes for COFF targets
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passes_repr_align_greater_than_target_max =
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alignment must not be greater than `isize::MAX` bytes
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.note = `isize::MAX` is {$size} for the current target

‎compiler/rustc_passes/src/check_attr.rs

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@@ -36,13 +36,18 @@ use rustc_session::lint::builtin::{
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};
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use rustc_session::parse::feature_err;
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use rustc_span::{BytePos, DUMMY_SP, Span, Symbol, edition, kw, sym};
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use rustc_target::spec::BinaryFormat;
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use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
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use rustc_trait_selection::infer::{TyCtxtInferExt, ValuePairs};
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use rustc_trait_selection::traits::ObligationCtxt;
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use tracing::debug;
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use crate::{errors, fluent_generated as fluent};
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// Max alignment supported for PE-COFF binary format.
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// See https://learn.microsoft.com/en-us/cpp/cpp/align-cpp?view=msvc-170
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const COFF_MAX_ALIGN_BYTES: u64 = 0x2000;
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#[derive(LintDiagnostic)]
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#[diag(passes_diagnostic_diagnostic_on_unimplemented_only_for_traits)]
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struct DiagnosticOnUnimplementedOnlyForTraits;
@@ -2171,6 +2176,12 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
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}
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fn check_align_value(&self, align: Align, span: Span) {
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if self.tcx.sess.target.binary_format == BinaryFormat::Coff {
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if align.bytes() > COFF_MAX_ALIGN_BYTES {
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self.dcx().emit_err(errors::InvalidReprAlignForCoff { span });
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}
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}
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if align.bytes() > 2_u64.pow(29) {
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// for values greater than 2^29, a different error will be emitted, make sure that happens
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self.dcx().span_delayed_bug(

‎compiler/rustc_passes/src/errors.rs

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@@ -597,6 +597,13 @@ pub(crate) struct InvalidReprAlignForTarget {
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pub size: u64,
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}
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#[derive(Diagnostic)]
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#[diag(passes_repr_align_greater_than_coff_max, code = E0806)]
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pub(crate) struct InvalidReprAlignForCoff {
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#[primary_span]
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pub span: Span,
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}
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#[derive(LintDiagnostic)]
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#[diag(passes_repr_conflicting, code = E0566)]
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pub(crate) struct ReprConflictingLint;

‎tests/ui/repr/repr-align.stderr renamed to ‎tests/ui/repr/repr-align.notwin.stderr

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@@ -1,51 +1,75 @@
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error[E0589]: invalid `repr(align)` attribute: not an unsuffixed integer
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--> $DIR/repr-align.rs:3:14
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--> $DIR/repr-align.rs:8:14
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|
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LL | #[repr(align(16.0))]
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| ^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:6:14
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--> $DIR/repr-align.rs:11:14
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|
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LL | #[repr(align(15))]
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| ^^
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error[E0589]: invalid `repr(align)` attribute: larger than 2^29
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--> $DIR/repr-align.rs:9:14
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--> $DIR/repr-align.rs:14:14
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|
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LL | #[repr(align(4294967296))]
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| ^^^^^^^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:15:14
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--> $DIR/repr-align.rs:21:14
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|
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LL | #[repr(align(0))]
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| ^
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error[E0589]: invalid `repr(align)` attribute: not an unsuffixed integer
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--> $DIR/repr-align.rs:18:14
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--> $DIR/repr-align.rs:27:14
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|
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LL | #[repr(align(16.0))]
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| ^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:21:14
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--> $DIR/repr-align.rs:30:14
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|
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LL | #[repr(align(15))]
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| ^^
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error[E0589]: invalid `repr(align)` attribute: larger than 2^29
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--> $DIR/repr-align.rs:24:14
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--> $DIR/repr-align.rs:33:14
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|
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LL | #[repr(align(4294967296))]
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| ^^^^^^^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:30:14
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--> $DIR/repr-align.rs:40:14
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|
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LL | #[repr(align(0))]
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| ^
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error: aborting due to 8 previous errors
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error[E0589]: invalid alignment value: not an unsuffixed integer
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--> $DIR/repr-align.rs:46:9
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|
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LL | #[align(16.0)]
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| ^^^^
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error[E0589]: invalid alignment value: not a power of two
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--> $DIR/repr-align.rs:49:9
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|
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LL | #[align(15)]
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| ^^
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error[E0589]: invalid alignment value: larger than 2^29
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--> $DIR/repr-align.rs:52:9
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|
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LL | #[align(4294967296)]
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| ^^^^^^^^^^
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error[E0589]: invalid alignment value: not a power of two
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--> $DIR/repr-align.rs:59:9
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|
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LL | #[align(0)]
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| ^
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error: aborting due to 12 previous errors
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For more information about this error, try `rustc --explain E0589`.

‎tests/ui/repr/repr-align.rs

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@@ -1,33 +1,65 @@
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//@ revisions: win notwin
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//@[win] only-windows
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//@[notwin] ignore-windows
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#![feature(fn_align)]
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#![allow(dead_code)]
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3-
#[repr(align(16.0))] //~ ERROR: invalid `repr(align)` attribute: not an unsuffixed integer
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#[repr(align(16.0))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not an unsuffixed integer
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struct S0(i32);
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6-
#[repr(align(15))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
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#[repr(align(15))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not a power of two
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struct S1(i32);
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9-
#[repr(align(4294967296))] //~ ERROR: invalid `repr(align)` attribute: larger than 2^29
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#[repr(align(4294967296))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: larger than 2^29
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struct S2(i32);
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#[repr(align(536870912))] // ok: this is the largest accepted alignment
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#[repr(align(536870912))] //[win]~ ERROR: alignment must not be greater than 8192 bytes for COFF targets
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// notwin: this is the largest accepted alignment
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struct S3(i32);
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15-
#[repr(align(0))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
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#[repr(align(0))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not a power of two
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struct S4(i32);
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18-
#[repr(align(16.0))] //~ ERROR: invalid `repr(align)` attribute: not an unsuffixed integer
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#[repr(align(16384))] //[win]~ ERROR: alignment must not be greater than 8192 bytes for COFF targets
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struct S5(i32);
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27+
#[repr(align(16.0))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not an unsuffixed integer
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enum E0 { A, B }
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#[repr(align(15))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
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#[repr(align(15))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not a power of two
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enum E1 { A, B }
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24-
#[repr(align(4294967296))] //~ ERROR: invalid `repr(align)` attribute: larger than 2^29
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#[repr(align(4294967296))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: larger than 2^29
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enum E2 { A, B }
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27-
#[repr(align(536870912))] // ok: this is the largest accepted alignment
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#[repr(align(536870912))] //[win]~ ERROR: alignment must not be greater than 8192 bytes for COFF targets
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// notwin: this is the largest accepted alignment
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enum E3 { A, B }
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30-
#[repr(align(0))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
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#[repr(align(0))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not a power of two
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enum E4 { A, B }
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#[repr(align(16384))] //[win]~ ERROR: alignment must not be greater than 8192 bytes for COFF targets
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enum E5 { A, B }
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#[align(16.0)] //[notwin,win]~ ERROR: invalid alignment value: not an unsuffixed integer
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fn f0() {}
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#[align(15)] //[notwin,win]~ ERROR: invalid alignment value: not a power of two
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fn f1() {}
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#[align(4294967296)] //[notwin,win]~ ERROR: alignment value: larger than 2^29
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fn f2() {}
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#[align(536870912)] //[win]~ ERROR: alignment must not be greater than 8192 bytes for COFF targets
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// notwin: this is the largest accepted alignment
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fn f3() {}
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#[align(0)] //[notwin,win]~ ERROR: alignment value: not a power of two
60+
fn f4() {}
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#[align(16384)] //[win]~ ERROR: alignment must not be greater than 8192 bytes for COFF targets
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fn f5() {}
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fn main() {}

‎tests/ui/repr/repr-align.win.stderr

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error[E0589]: invalid `repr(align)` attribute: not an unsuffixed integer
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--> $DIR/repr-align.rs:8:14
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|
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LL | #[repr(align(16.0))]
5+
| ^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
8+
--> $DIR/repr-align.rs:11:14
9+
|
10+
LL | #[repr(align(15))]
11+
| ^^
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error[E0589]: invalid `repr(align)` attribute: larger than 2^29
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--> $DIR/repr-align.rs:14:14
15+
|
16+
LL | #[repr(align(4294967296))]
17+
| ^^^^^^^^^^
18+
19+
error[E0589]: invalid `repr(align)` attribute: not a power of two
20+
--> $DIR/repr-align.rs:21:14
21+
|
22+
LL | #[repr(align(0))]
23+
| ^
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25+
error[E0589]: invalid `repr(align)` attribute: not an unsuffixed integer
26+
--> $DIR/repr-align.rs:27:14
27+
|
28+
LL | #[repr(align(16.0))]
29+
| ^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
32+
--> $DIR/repr-align.rs:30:14
33+
|
34+
LL | #[repr(align(15))]
35+
| ^^
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37+
error[E0589]: invalid `repr(align)` attribute: larger than 2^29
38+
--> $DIR/repr-align.rs:33:14
39+
|
40+
LL | #[repr(align(4294967296))]
41+
| ^^^^^^^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
44+
--> $DIR/repr-align.rs:40:14
45+
|
46+
LL | #[repr(align(0))]
47+
| ^
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49+
error[E0589]: invalid alignment value: not an unsuffixed integer
50+
--> $DIR/repr-align.rs:46:9
51+
|
52+
LL | #[align(16.0)]
53+
| ^^^^
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55+
error[E0589]: invalid alignment value: not a power of two
56+
--> $DIR/repr-align.rs:49:9
57+
|
58+
LL | #[align(15)]
59+
| ^^
60+
61+
error[E0589]: invalid alignment value: larger than 2^29
62+
--> $DIR/repr-align.rs:52:9
63+
|
64+
LL | #[align(4294967296)]
65+
| ^^^^^^^^^^
66+
67+
error[E0589]: invalid alignment value: not a power of two
68+
--> $DIR/repr-align.rs:59:9
69+
|
70+
LL | #[align(0)]
71+
| ^
72+
73+
error[E0806]: alignment must not be greater than 8192 bytes for COFF targets
74+
--> $DIR/repr-align.rs:17:8
75+
|
76+
LL | #[repr(align(536870912))]
77+
| ^^^^^^^^^^^^^^^^
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79+
error[E0806]: alignment must not be greater than 8192 bytes for COFF targets
80+
--> $DIR/repr-align.rs:24:8
81+
|
82+
LL | #[repr(align(16384))]
83+
| ^^^^^^^^^^^^
84+
85+
error[E0806]: alignment must not be greater than 8192 bytes for COFF targets
86+
--> $DIR/repr-align.rs:36:8
87+
|
88+
LL | #[repr(align(536870912))]
89+
| ^^^^^^^^^^^^^^^^
90+
91+
error[E0806]: alignment must not be greater than 8192 bytes for COFF targets
92+
--> $DIR/repr-align.rs:43:8
93+
|
94+
LL | #[repr(align(16384))]
95+
| ^^^^^^^^^^^^
96+
97+
error[E0806]: alignment must not be greater than 8192 bytes for COFF targets
98+
--> $DIR/repr-align.rs:55:1
99+
|
100+
LL | #[align(536870912)]
101+
| ^^^^^^^^^^^^^^^^^^^
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103+
error[E0806]: alignment must not be greater than 8192 bytes for COFF targets
104+
--> $DIR/repr-align.rs:62:1
105+
|
106+
LL | #[align(16384)]
107+
| ^^^^^^^^^^^^^^^
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109+
error: aborting due to 18 previous errors
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Some errors have detailed explanations: E0589, E0806.
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For more information about an error, try `rustc --explain E0589`.

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