Change how AssocItem is reported.

Currently it's reported as either `TraitItem` or `ImplItem`. This commit
changes it to `AssocItem`, because having the report match the type name
is (a) consistent with other types, and (b) the trait/impl split isn't
that important here.

Author: nnethercote

compiler/rustc_passes/src/hir_stats.rs

@@ -333,11 +333,7 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
     }
 
     fn visit_assoc_item(&mut self, item: &'v ast::AssocItem, ctxt: ast_visit::AssocCtxt) {
-        let label = match ctxt {
-            ast_visit::AssocCtxt::Trait => "TraitItem",
-            ast_visit::AssocCtxt::Impl => "ImplItem",
-        };
-        self.record(label, Id::None, item);
+        self.record("AssocItem", Id::None, item);
         ast_visit::walk_assoc_item(self, item, ctxt);
     }
 

src/test/ui/stats/hir-stats.stderr

@@ -17,10 +17,9 @@ FnDecl                           200             5            40
 Variant                          240             2           120
 Block                            288             6            48
 Attribute                        304             2           152
-ImplItem                         320             2           160
-TraitItem                        320             2           160
 GenericBound                     352             4            88
 GenericParam                     520             5           104
+AssocItem                        640             4           160
 PathSegment                      720            30            24
 Expr                             832             8           104
 Pat                              840             7           120
@@ -48,11 +47,10 @@ Param                            160             4            40
 FnDecl                           200             5            40
 Variant                          240             2           120
 Block                            288             6            48
-ImplItem                         320             2           160
-TraitItem                        320             2           160
 GenericBound                     352             4            88
 GenericParam                     520             5           104
 Attribute                        608             4           152
+AssocItem                        640             4           160
 PathSegment                      792            33            24
 Pat                              840             7           120
 Expr                             936             9           104