Rollup merge of #130235 - compiler-errors:nested-if, r=michaelwoerister

Simplify some nested `if` statements

Applies some but not all instances of `clippy::collapsible_if`. Some ended up looking worse afterwards, though, so I left those out. Also applies instances of `clippy::collapsible_else_if`

Review with whitespace disabled please.

Author: Zalathar

compiler/rustc_ast/src/entry.rs

@@ -45,18 +45,16 @@ pub fn entry_point_type(
         EntryPointType::Start
     } else if attr::contains_name(attrs, sym::rustc_main) {
         EntryPointType::RustcMainAttr
-    } else {
-        if let Some(name) = name
-            && name == sym::main
-        {
-            if at_root {
-                // This is a top-level function so it can be `main`.
-                EntryPointType::MainNamed
-            } else {
-                EntryPointType::OtherMain
-            }
+    } else if let Some(name) = name
+        && name == sym::main
+    {
+        if at_root {
+            // This is a top-level function so it can be `main`.
+            EntryPointType::MainNamed
         } else {
-            EntryPointType::None
+            EntryPointType::OtherMain
         }
+    } else {
+        EntryPointType::None
     }
 }

compiler/rustc_ast_lowering/src/index.rs

@@ -78,26 +78,24 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
 
         // Make sure that the DepNode of some node coincides with the HirId
         // owner of that node.
-        if cfg!(debug_assertions) {
-            if hir_id.owner != self.owner {
-                span_bug!(
-                    span,
-                    "inconsistent HirId at `{:?}` for `{:?}`: \
+        if cfg!(debug_assertions) && hir_id.owner != self.owner {
+            span_bug!(
+                span,
+                "inconsistent HirId at `{:?}` for `{:?}`: \
                      current_dep_node_owner={} ({:?}), hir_id.owner={} ({:?})",
-                    self.tcx.sess.source_map().span_to_diagnostic_string(span),
-                    node,
-                    self.tcx
-                        .definitions_untracked()
-                        .def_path(self.owner.def_id)
-                        .to_string_no_crate_verbose(),
-                    self.owner,
-                    self.tcx
-                        .definitions_untracked()
-                        .def_path(hir_id.owner.def_id)
-                        .to_string_no_crate_verbose(),
-                    hir_id.owner,
-                )
-            }
+                self.tcx.sess.source_map().span_to_diagnostic_string(span),
+                node,
+                self.tcx
+                    .definitions_untracked()
+                    .def_path(self.owner.def_id)
+                    .to_string_no_crate_verbose(),
+                self.owner,
+                self.tcx
+                    .definitions_untracked()
+                    .def_path(hir_id.owner.def_id)
+                    .to_string_no_crate_verbose(),
+                hir_id.owner,
+            )
         }
 
         self.nodes[hir_id.local_id] = ParentedNode { parent: self.parent_node, node };