Auto merge of #52381 - oli-obk:ty_to_def_id, r=eddyb

Remove `ty_to_def_id`

fixes https://github.com/rust-lang/rust/issues/52341

The uses were mostly convenience and generally "too powerful" (would also have worked for types that weren't interesting at the use site)

r? @eddyb

src/librustc/middle/dead.rs

@@ -469,13 +469,9 @@ fn should_warn_about_item(&mut self, item: &hir::Item) -> bool {
 
     fn should_warn_about_field(&mut self, field: &hir::StructField) -> bool {
         let field_type = self.tcx.type_of(self.tcx.hir.local_def_id(field.id));
-        let is_marker_field = match field_type.ty_to_def_id() {
-            Some(def_id) => self.tcx.lang_items().items().iter().any(|item| *item == Some(def_id)),
-            _ => false
-        };
         !field.is_positional()
             && !self.symbol_is_live(field.id, None)
-            && !is_marker_field
+            && !field_type.is_phantom_data()
             && !has_allow_dead_code_or_lang_attr(self.tcx, field.id, &field.attrs)
     }
 

src/librustc/traits/error_reporting.rs

@@ -391,7 +391,7 @@ fn on_unimplemented_note(
             flags.push((name, Some(value)));
         }
 
-        if let Some(true) = self_ty.ty_to_def_id().map(|def_id| def_id.is_local()) {
+        if let Some(true) = self_ty.ty_adt_def().map(|def| def.did.is_local()) {
             flags.push(("crate_local".to_string(), None));
         }
 
@@ -775,7 +775,13 @@ pub fn report_selection_error(&self,
                 }
                 let found_trait_ty = found_trait_ref.self_ty();
 
-                let found_did = found_trait_ty.ty_to_def_id();
+                let found_did = match found_trait_ty.sty {
+                    ty::TyClosure(did, _) |
+                    ty::TyForeign(did) |
+                    ty::TyFnDef(did, _) => Some(did),
+                    ty::TyAdt(def, _) => Some(def.did),
+                    _ => None,
+                };
                 let found_span = found_did.and_then(|did| {
                     self.tcx.hir.span_if_local(did)
                 }).map(|sp| self.tcx.sess.codemap().def_span(sp)); // the sp could be an fn def

src/librustc/ty/sty.rs

@@ -1767,17 +1767,6 @@ pub fn is_impl_trait(&self) -> bool {
         }
     }
 
-    pub fn ty_to_def_id(&self) -> Option<DefId> {
-        match self.sty {
-            TyDynamic(ref tt, ..) => tt.principal().map(|p| p.def_id()),
-            TyAdt(def, _) => Some(def.did),
-            TyForeign(did) => Some(did),
-            TyClosure(id, _) => Some(id),
-            TyFnDef(id, _) => Some(id),
-            _ => None,
-        }
-    }
-
     pub fn ty_adt_def(&self) -> Option<&'tcx AdtDef> {
         match self.sty {
             TyAdt(adt, _) => Some(adt),

src/librustc_codegen_llvm/back/write.rs

@@ -399,7 +399,7 @@ pub(crate) fn save_temp_bitcode(&self, module: &ModuleCodegen, name: &str) {
 }
 
 struct DiagnosticHandlers<'a> {
-    inner: Box<(&'a CodegenContext, &'a Handler)>,
+    data: *mut (&'a CodegenContext, &'a Handler),
     llcx: ContextRef,
 }
 
@@ -407,24 +407,22 @@ impl<'a> DiagnosticHandlers<'a> {
     fn new(cgcx: &'a CodegenContext,
            handler: &'a Handler,
            llcx: ContextRef) -> DiagnosticHandlers<'a> {
-        let data = Box::new((cgcx, handler));
+        let data = Box::into_raw(Box::new((cgcx, handler)));
         unsafe {
-            let arg = &*data as &(_, _) as *const _ as *mut _;
-            llvm::LLVMRustSetInlineAsmDiagnosticHandler(llcx, inline_asm_handler, arg);
-            llvm::LLVMContextSetDiagnosticHandler(llcx, diagnostic_handler, arg);
-        }
-        DiagnosticHandlers {
-            inner: data,
-            llcx: llcx,
+            llvm::LLVMRustSetInlineAsmDiagnosticHandler(llcx, inline_asm_handler, data as *mut _);
+            llvm::LLVMContextSetDiagnosticHandler(llcx, diagnostic_handler, data as *mut _);
         }
+        DiagnosticHandlers { data, llcx }
     }
 }
 
 impl<'a> Drop for DiagnosticHandlers<'a> {
     fn drop(&mut self) {
+        use std::ptr::null_mut;
         unsafe {
-            llvm::LLVMRustSetInlineAsmDiagnosticHandler(self.llcx, inline_asm_handler, 0 as *mut _);
-            llvm::LLVMContextSetDiagnosticHandler(self.llcx, diagnostic_handler, 0 as *mut _);
+            llvm::LLVMRustSetInlineAsmDiagnosticHandler(self.llcx, inline_asm_handler, null_mut());
+            llvm::LLVMContextSetDiagnosticHandler(self.llcx, diagnostic_handler, null_mut());
+            drop(Box::from_raw(self.data));
         }
     }
 }

src/librustc_lint/builtin.rs

@@ -591,8 +591,8 @@ fn check_item(&mut self, cx: &LateContext, item: &hir::Item) {
         if self.impling_types.is_none() {
             let mut impls = NodeSet();
             cx.tcx.for_each_impl(debug, |d| {
-                if let Some(ty_def) = cx.tcx.type_of(d).ty_to_def_id() {
-                    if let Some(node_id) = cx.tcx.hir.as_local_node_id(ty_def) {
+                if let Some(ty_def) = cx.tcx.type_of(d).ty_adt_def() {
+                    if let Some(node_id) = cx.tcx.hir.as_local_node_id(ty_def.did) {
                         impls.insert(node_id);
                     }
                 }