Auto merge of #129359 - matthiaskrgr:rollup-nyre44t, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

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

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

3 files changed, 17 insertions, 8 deletions

diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs b/compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs
index 5a08f2f00e5..e91bcea16a2 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs
+++ b/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);
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
index 87bea22d8dd..30f90bada9a 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
+++ b/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
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
index b23e05182ca..eb446d2d7b2 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
@@ -109,7 +109,7 @@ 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 {
@@ -117,7 +117,7 @@ impl<'ll, 'tcx> CodegenUnitDebugContext<'ll, 'tcx> {
                 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) }
     }