Auto merge of #139309 - RalfJung:abi_unsupported_vector_types, r=fee1-dead,traviscross

make abi_unsupported_vector_types a hard error

Fixes https://github.com/rust-lang/rust/issues/116558 by completing the transition; see that issue for context. The lint was introduced with Rust 1.84 and this has been shown in cargo's future breakage reports since Rust 1.85, released 6 weeks ago, and so far we got 0 complaints by users. There's not even a backlink on the tracking issue. We did a [crater run](https://github.com/rust-lang/rust/pull/127731#issuecomment-2286736295) when the lint was originally added and found no breakage. So I don't think we need another crater run now, but I can do one if the team prefers that.

https://github.com/rust-lang/rust/issues/131800 is done, so for most current targets (in particular, all tier 1 and tier 2 targets) we have the information to implement this check (modulo the targets where we don't properly support SIMD vectors yet, see the sub-issues of https://github.com/rust-lang/rust/issues/116558). If a new target gets added in the future, it will default to reject all SIMD vector types until proper information is added, which is the default we want.

This will need approval by for `@rust-lang/lang.` Cc `@workingjubilee` `@veluca93`

try-job: test-various
try-job: armhf-gnu
try-job: dist-i586-gnu-i586-i686-musl

2 files changed, 16 insertions, 24 deletions

diff --git a/compiler/rustc_monomorphize/src/errors.rs b/compiler/rustc_monomorphize/src/errors.rs
index adfe096f0cd..0dd20bbb35f 100644
--- a/compiler/rustc_monomorphize/src/errors.rs
+++ b/compiler/rustc_monomorphize/src/errors.rs
@@ -70,10 +70,11 @@ pub(crate) struct UnknownCguCollectionMode<'a> {
     pub mode: &'a str,
 }
 
-#[derive(LintDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(monomorphize_abi_error_disabled_vector_type)]
 #[help]
 pub(crate) struct AbiErrorDisabledVectorType<'a> {
+    #[primary_span]
     #[label]
     pub span: Span,
     pub required_feature: &'a str,
@@ -82,9 +83,10 @@ pub(crate) struct AbiErrorDisabledVectorType<'a> {
     pub is_call: bool,
 }
 
-#[derive(LintDiagnostic)]
+#[derive(Diagnostic)]
 #[diag(monomorphize_abi_error_unsupported_vector_type)]
 pub(crate) struct AbiErrorUnsupportedVectorType<'a> {
+    #[primary_span]
     #[label]
     pub span: Span,
     pub ty: Ty<'a>,
diff --git a/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs b/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs
index 94ee34c8b7b..2ef23d7a21d 100644
--- a/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs
+++ b/compiler/rustc_monomorphize/src/mono_checks/abi_check.rs
@@ -5,7 +5,7 @@ use rustc_hir::{CRATE_HIR_ID, HirId};
 use rustc_middle::mir::{self, Location, traversal};
 use rustc_middle::ty::layout::LayoutCx;
 use rustc_middle::ty::{self, Instance, InstanceKind, Ty, TyCtxt, TypingEnv};
-use rustc_session::lint::builtin::{ABI_UNSUPPORTED_VECTOR_TYPES, WASM_C_ABI};
+use rustc_session::lint::builtin::WASM_C_ABI;
 use rustc_span::def_id::DefId;
 use rustc_span::{DUMMY_SP, Span, Symbol, sym};
 use rustc_target::callconv::{ArgAbi, Conv, FnAbi, PassMode};
@@ -50,34 +50,24 @@ fn do_check_simd_vector_abi<'tcx>(
             let feature = match feature_def.iter().find(|(bits, _)| size.bits() <= *bits) {
                 Some((_, feature)) => feature,
                 None => {
-                    let (span, hir_id) = loc();
-                    tcx.emit_node_span_lint(
-                        ABI_UNSUPPORTED_VECTOR_TYPES,
-                        hir_id,
+                    let (span, _hir_id) = loc();
+                    tcx.dcx().emit_err(errors::AbiErrorUnsupportedVectorType {
                         span,
-                        errors::AbiErrorUnsupportedVectorType {
-                            span,
-                            ty: arg_abi.layout.ty,
-                            is_call,
-                        },
-                    );
+                        ty: arg_abi.layout.ty,
+                        is_call,
+                    });
                     continue;
                 }
             };
             if !have_feature(Symbol::intern(feature)) {
                 // Emit error.
-                let (span, hir_id) = loc();
-                tcx.emit_node_span_lint(
-                    ABI_UNSUPPORTED_VECTOR_TYPES,
-                    hir_id,
+                let (span, _hir_id) = loc();
+                tcx.dcx().emit_err(errors::AbiErrorDisabledVectorType {
                     span,
-                    errors::AbiErrorDisabledVectorType {
-                        span,
-                        required_feature: feature,
-                        ty: arg_abi.layout.ty,
-                        is_call,
-                    },
-                );
+                    required_feature: feature,
+                    ty: arg_abi.layout.ty,
+                    is_call,
+                });
             }
         }
     }