Auto merge of rust-lang#129359 - matthiaskrgr:rollup-nyre44t, r=matth…

…iaskrgr

Rollup of 10 pull requests

Successful merges:

 - rust-lang#128627 (Special case DUMMY_SP to emit line 0/column 0 locations on DWARF platforms.)
 - rust-lang#128843 (Minor Refactor: Remove a Redundant Conditional Check)
 - rust-lang#129179 (CFI: Erase regions when projecting ADT to its transparent non-1zst field)
 - rust-lang#129281 (Tweak unreachable lint wording)
 - rust-lang#129312 (Fix stability attribute of `impl !Error for &str`)
 - rust-lang#129332 (Avoid extra `cast()`s after `CStr::as_ptr()`)
 - rust-lang#129339 (Make `ArgAbi::make_indirect_force` more specific)
 - rust-lang#129344 (Use `bool` in favor of `Option<()>` for diagnostics)
 - rust-lang#129345 (Use shorthand field initialization syntax more aggressively in the compiler)
 - rust-lang#129355 (fix comment on PlaceMention semantics)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_ast_lowering/src/asm.rs

@@ -86,9 +86,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                                 // Multiple different abi names may actually be the same ABI
                                 // If the specified ABIs are not the same name, alert the user that they resolve to the same ABI
                                 let source_map = self.tcx.sess.source_map();
-                                let equivalent = (source_map.span_to_snippet(*prev_sp)
-                                    != source_map.span_to_snippet(*abi_span))
-                                .then_some(());
+                                let equivalent = source_map.span_to_snippet(*prev_sp)
+                                    != source_map.span_to_snippet(*abi_span);
 
                                 self.dcx().emit_err(AbiSpecifiedMultipleTimes {
                                     abi_span: *abi_span,

compiler/rustc_ast_lowering/src/errors.rs

@@ -184,7 +184,7 @@ pub struct AbiSpecifiedMultipleTimes {
     #[label]
     pub prev_span: Span,
     #[note]
-    pub equivalent: Option<()>,
+    pub equivalent: bool,
 }
 
 #[derive(Diagnostic)]

compiler/rustc_ast_lowering/src/item.rs

@@ -1421,7 +1421,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         };
         hir::FnHeader {
             safety: self.lower_safety(h.safety, default_safety),
-            asyncness: asyncness,
+            asyncness,
             constness: self.lower_constness(h.constness),
             abi: self.lower_extern(h.ext),
         }

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -562,10 +562,8 @@ impl<'a> AstValidator<'a> {
         FnHeader { safety: _, coroutine_kind, constness, ext }: FnHeader,
     ) {
         let report_err = |span| {
-            self.dcx().emit_err(errors::FnQualifierInExtern {
-                span: span,
-                block: self.current_extern_span(),
-            });
+            self.dcx()
+                .emit_err(errors::FnQualifierInExtern { span, block: self.current_extern_span() });
         };
         match coroutine_kind {
             Some(knd) => report_err(knd.span()),
@@ -963,14 +961,13 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 self_ty,
                 items,
             }) => {
-                let error =
-                    |annotation_span, annotation, only_trait: bool| errors::InherentImplCannot {
-                        span: self_ty.span,
-                        annotation_span,
-                        annotation,
-                        self_ty: self_ty.span,
-                        only_trait: only_trait.then_some(()),
-                    };
+                let error = |annotation_span, annotation, only_trait| errors::InherentImplCannot {
+                    span: self_ty.span,
+                    annotation_span,
+                    annotation,
+                    self_ty: self_ty.span,
+                    only_trait,
+                };
 
                 self.with_in_trait_impl(None, |this| {
                     this.visibility_not_permitted(
@@ -1195,7 +1192,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 } else if where_clauses.after.has_where_token {
                     self.dcx().emit_err(errors::WhereClauseAfterTypeAlias {
                         span: where_clauses.after.span,
-                        help: self.session.is_nightly_build().then_some(()),
+                        help: self.session.is_nightly_build(),
                     });
                 }
             }

compiler/rustc_ast_passes/src/errors.rs

@@ -484,7 +484,7 @@ pub struct InherentImplCannot<'a> {
     #[label(ast_passes_type)]
     pub self_ty: Span,
     #[note(ast_passes_only_trait)]
-    pub only_trait: Option<()>,
+    pub only_trait: bool,
 }
 
 #[derive(Diagnostic)]
@@ -528,7 +528,7 @@ pub struct WhereClauseAfterTypeAlias {
     #[primary_span]
     pub span: Span,
     #[help]
-    pub help: Option<()>,
+    pub help: bool,
 }
 
 #[derive(Diagnostic)]

compiler/rustc_attr/src/builtin.rs

@@ -846,7 +846,7 @@ pub fn find_deprecation(
                                     sess.dcx().emit_err(
                                         session_diagnostics::DeprecatedItemSuggestion {
                                             span: mi.span,
-                                            is_nightly: sess.is_nightly_build().then_some(()),
+                                            is_nightly: sess.is_nightly_build(),
                                             details: (),
                                         },
                                     );

compiler/rustc_attr/src/session_diagnostics.rs

@@ -342,7 +342,7 @@ pub(crate) struct DeprecatedItemSuggestion {
     pub span: Span,
 
     #[help]
-    pub is_nightly: Option<()>,
+    pub is_nightly: bool,
 
     #[note]
     pub details: (),

compiler/rustc_codegen_llvm/src/allocator.rs

@@ -149,7 +149,7 @@ fn create_wrapper_function(
         }
         llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden);
 
-        let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, c"entry".as_ptr().cast());
+        let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, c"entry".as_ptr());
 
         let llbuilder = llvm::LLVMCreateBuilderInContext(llcx);
         llvm::LLVMPositionBuilderAtEnd(llbuilder, llbb);

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -616,7 +616,7 @@ pub(crate) fn run_pass_manager(
             llvm::LLVMRustAddModuleFlagU32(
                 module.module_llvm.llmod(),
                 llvm::LLVMModFlagBehavior::Error,
-                c"LTOPostLink".as_ptr().cast(),
+                c"LTOPostLink".as_ptr(),
                 1,
             );
         }

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -1031,7 +1031,7 @@ unsafe fn embed_bitcode(
             let llglobal = llvm::LLVMAddGlobal(
                 llmod,
                 common::val_ty(llconst),
-                c"rustc.embedded.module".as_ptr().cast(),
+                c"rustc.embedded.module".as_ptr(),
             );
             llvm::LLVMSetInitializer(llglobal, llconst);
 
@@ -1044,7 +1044,7 @@ unsafe fn embed_bitcode(
             let llglobal = llvm::LLVMAddGlobal(
                 llmod,
                 common::val_ty(llconst),
-                c"rustc.embedded.cmdline".as_ptr().cast(),
+                c"rustc.embedded.cmdline".as_ptr(),
             );
             llvm::LLVMSetInitializer(llglobal, llconst);
             let section = if is_apple {
@@ -1054,7 +1054,7 @@ unsafe fn embed_bitcode(
             } else {
                 c".llvmcmd"
             };
-            llvm::LLVMSetSection(llglobal, section.as_ptr().cast());
+            llvm::LLVMSetSection(llglobal, section.as_ptr());
             llvm::LLVMRustSetLinkage(llglobal, llvm::Linkage::PrivateLinkage);
         } else {
             // We need custom section flags, so emit module-level inline assembly.
@@ -1107,7 +1107,7 @@ fn create_msvc_imps(
             .collect::<Vec<_>>();
 
         for (imp_name, val) in globals {
-            let imp = llvm::LLVMAddGlobal(llmod, ptr_ty, imp_name.as_ptr().cast());
+            let imp = llvm::LLVMAddGlobal(llmod, ptr_ty, imp_name.as_ptr());
             llvm::LLVMSetInitializer(imp, val);
             llvm::LLVMRustSetLinkage(imp, llvm::Linkage::ExternalLinkage);
         }

compiler/rustc_codegen_llvm/src/consts.rs

@@ -525,7 +525,7 @@ impl<'ll> CodegenCx<'ll, '_> {
                     let val = llvm::LLVMMetadataAsValue(self.llcx, meta);
                     llvm::LLVMAddNamedMetadataOperand(
                         self.llmod,
-                        c"wasm.custom_sections".as_ptr().cast(),
+                        c"wasm.custom_sections".as_ptr(),
                         val,
                     );
                 }

compiler/rustc_codegen_llvm/src/context.rs

@@ -207,15 +207,15 @@ pub unsafe fn create_module<'ll>(
     // If skipping the PLT is enabled, we need to add some module metadata
     // to ensure intrinsic calls don't use it.
     if !sess.needs_plt() {
-        let avoid_plt = c"RtLibUseGOT".as_ptr().cast();
+        let avoid_plt = c"RtLibUseGOT".as_ptr();
         unsafe {
             llvm::LLVMRustAddModuleFlagU32(llmod, llvm::LLVMModFlagBehavior::Warning, avoid_plt, 1);
         }
     }
 
     // Enable canonical jump tables if CFI is enabled. (See https://reviews.llvm.org/D65629.)
     if sess.is_sanitizer_cfi_canonical_jump_tables_enabled() && sess.is_sanitizer_cfi_enabled() {
-        let canonical_jump_tables = c"CFI Canonical Jump Tables".as_ptr().cast();
+        let canonical_jump_tables = c"CFI Canonical Jump Tables".as_ptr();
         unsafe {
             llvm::LLVMRustAddModuleFlagU32(
                 llmod,
@@ -228,7 +228,7 @@ pub unsafe fn create_module<'ll>(
 
     // Enable LTO unit splitting if specified or if CFI is enabled. (See https://reviews.llvm.org/D53891.)
     if sess.is_split_lto_unit_enabled() || sess.is_sanitizer_cfi_enabled() {
-        let enable_split_lto_unit = c"EnableSplitLTOUnit".as_ptr().cast();
+        let enable_split_lto_unit = c"EnableSplitLTOUnit".as_ptr();
         unsafe {
             llvm::LLVMRustAddModuleFlagU32(
                 llmod,
@@ -241,7 +241,7 @@ pub unsafe fn create_module<'ll>(
 
     // Add "kcfi" module flag if KCFI is enabled. (See https://reviews.llvm.org/D119296.)
     if sess.is_sanitizer_kcfi_enabled() {
-        let kcfi = c"kcfi".as_ptr().cast();
+        let kcfi = c"kcfi".as_ptr();
         unsafe {
             llvm::LLVMRustAddModuleFlagU32(llmod, llvm::LLVMModFlagBehavior::Override, kcfi, 1);
         }
@@ -280,26 +280,26 @@ pub unsafe fn create_module<'ll>(
                 llvm::LLVMRustAddModuleFlagU32(
                     llmod,
                     llvm::LLVMModFlagBehavior::Min,
-                    c"branch-target-enforcement".as_ptr().cast(),
+                    c"branch-target-enforcement".as_ptr(),
                     bti.into(),
                 );
                 llvm::LLVMRustAddModuleFlagU32(
                     llmod,
                     llvm::LLVMModFlagBehavior::Min,
-                    c"sign-return-address".as_ptr().cast(),
+                    c"sign-return-address".as_ptr(),
                     pac_ret.is_some().into(),
                 );
                 let pac_opts = pac_ret.unwrap_or(PacRet { leaf: false, key: PAuthKey::A });
                 llvm::LLVMRustAddModuleFlagU32(
                     llmod,
                     llvm::LLVMModFlagBehavior::Min,
-                    c"sign-return-address-all".as_ptr().cast(),
+                    c"sign-return-address-all".as_ptr(),
                     pac_opts.leaf.into(),
                 );
                 llvm::LLVMRustAddModuleFlagU32(
                     llmod,
                     llvm::LLVMModFlagBehavior::Min,
-                    c"sign-return-address-with-bkey".as_ptr().cast(),
+                    c"sign-return-address-with-bkey".as_ptr(),
                     u32::from(pac_opts.key == PAuthKey::B),
                 );
             }
@@ -317,7 +317,7 @@ pub unsafe fn create_module<'ll>(
             llvm::LLVMRustAddModuleFlagU32(
                 llmod,
                 llvm::LLVMModFlagBehavior::Override,
-                c"cf-protection-branch".as_ptr().cast(),
+                c"cf-protection-branch".as_ptr(),
                 1,
             );
         }
@@ -327,7 +327,7 @@ pub unsafe fn create_module<'ll>(
             llvm::LLVMRustAddModuleFlagU32(
                 llmod,
                 llvm::LLVMModFlagBehavior::Override,
-                c"cf-protection-return".as_ptr().cast(),
+                c"cf-protection-return".as_ptr(),
                 1,
             );
         }
@@ -338,7 +338,7 @@ pub unsafe fn create_module<'ll>(
             llvm::LLVMRustAddModuleFlagU32(
                 llmod,
                 llvm::LLVMModFlagBehavior::Error,
-                c"Virtual Function Elim".as_ptr().cast(),
+                c"Virtual Function Elim".as_ptr(),
                 1,
             );
         }

compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs

@@ -34,8 +34,7 @@ pub fn get_or_insert_gdb_debug_scripts_section_global<'ll>(cx: &CodegenCx<'ll, '
     let c_section_var_name = c"__rustc_debug_gdb_scripts_section__";
     let section_var_name = c_section_var_name.to_str().unwrap();
 
-    let section_var =
-        unsafe { llvm::LLVMGetNamedGlobal(cx.llmod, c_section_var_name.as_ptr().cast()) };
+    let section_var = unsafe { llvm::LLVMGetNamedGlobal(cx.llmod, c_section_var_name.as_ptr()) };
 
     section_var.unwrap_or_else(|| {
         let mut section_contents = Vec::new();
@@ -70,7 +69,7 @@ pub fn get_or_insert_gdb_debug_scripts_section_global<'ll>(cx: &CodegenCx<'ll, '
             let section_var = cx
                 .define_global(section_var_name, llvm_type)
                 .unwrap_or_else(|| bug!("symbol `{}` is already defined", section_var_name));
-            llvm::LLVMSetSection(section_var, c".debug_gdb_scripts".as_ptr().cast());
+            llvm::LLVMSetSection(section_var, c".debug_gdb_scripts".as_ptr());
             llvm::LLVMSetInitializer(section_var, cx.const_bytes(section_contents));
             llvm::LLVMSetGlobalConstant(section_var, llvm::True);
             llvm::LLVMSetUnnamedAddress(section_var, llvm::UnnamedAddr::Global);

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -952,7 +952,7 @@ pub fn build_compile_unit_di_node<'ll, 'tcx>(
             producer.as_ptr().cast(),
             producer.len(),
             tcx.sess.opts.optimize != config::OptLevel::No,
-            c"".as_ptr().cast(),
+            c"".as_ptr(),
             0,
             // NB: this doesn't actually have any perceptible effect, it seems. LLVM will instead
             // put the path supplied to `MCSplitDwarfFile` into the debug info of the final

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -109,15 +109,15 @@ impl<'ll, 'tcx> CodegenUnitDebugContext<'ll, 'tcx> {
                 llvm::LLVMRustAddModuleFlagU32(
                     self.llmod,
                     llvm::LLVMModFlagBehavior::Warning,
-                    c"Dwarf Version".as_ptr().cast(),
+                    c"Dwarf Version".as_ptr(),
                     dwarf_version,
                 );
             } else {
                 // Indicate that we want CodeView debug information on MSVC
                 llvm::LLVMRustAddModuleFlagU32(
                     self.llmod,
                     llvm::LLVMModFlagBehavior::Warning,
-                    c"CodeView".as_ptr().cast(),
+                    c"CodeView".as_ptr(),
                     1,
                 )
             }
@@ -126,7 +126,7 @@ impl<'ll, 'tcx> CodegenUnitDebugContext<'ll, 'tcx> {
             llvm::LLVMRustAddModuleFlagU32(
                 self.llmod,
                 llvm::LLVMModFlagBehavior::Warning,
-                c"Debug Info Version".as_ptr().cast(),
+                c"Debug Info Version".as_ptr(),
                 llvm::LLVMRustDebugMetadataVersion(),
             );
         }
@@ -570,7 +570,17 @@ impl<'ll, 'tcx> DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         inlined_at: Option<&'ll DILocation>,
         span: Span,
     ) -> &'ll DILocation {
-        let DebugLoc { line, col, .. } = self.lookup_debug_loc(span.lo());
+        // When emitting debugging information, DWARF (i.e. everything but MSVC)
+        // treats line 0 as a magic value meaning that the code could not be
+        // attributed to any line in the source. That's also exactly what dummy
+        // spans are. Make that equivalence here, rather than passing dummy spans
+        // to lookup_debug_loc, which will return line 1 for them.
+        let (line, col) = if span.is_dummy() && !self.sess().target.is_like_msvc {
+            (0, 0)
+        } else {
+            let DebugLoc { line, col, .. } = self.lookup_debug_loc(span.lo());
+            (line, col)
+        };
 
         unsafe { llvm::LLVMRustDIBuilderCreateDebugLocation(line, col, scope, inlined_at) }
     }

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -1500,7 +1500,7 @@ impl<'a> Linker for L4Bender<'a> {
 
 impl<'a> L4Bender<'a> {
     pub fn new(cmd: Command, sess: &'a Session) -> L4Bender<'a> {
-        L4Bender { cmd, sess: sess, hinted_static: false }
+        L4Bender { cmd, sess, hinted_static: false }
     }
 
     fn hint_static(&mut self) {
@@ -1520,7 +1520,7 @@ pub struct AixLinker<'a> {
 
 impl<'a> AixLinker<'a> {
     pub fn new(cmd: Command, sess: &'a Session) -> AixLinker<'a> {
-        AixLinker { cmd, sess: sess, hinted_static: None }
+        AixLinker { cmd, sess, hinted_static: None }
     }
 
     fn hint_static(&mut self) {