Auto merge of #67764 - Centril:rollup-ycbq3os, r=Centril

Rollup of 6 pull requests

Successful merges:

 - #67574 (Extract `rustc_ast_lowering` crate from `rustc`)
 - #67685 (Constify Result)
 - #67702 (Add symbol normalization for proc_macro_server.)
 - #67730 (Cleanup pattern type checking, fix diagnostics bugs (+ improvements))
 - #67744 (parser: reduce diversity in error handling mechanisms)
 - #67748 (Use function attribute "frame-pointer" instead of "no-frame-pointer-elim")

Failed merges:

r? @ghost

Author: bors

Cargo.lock

@@ -3358,6 +3358,22 @@ dependencies = [
  "core",
 ]
 
+[[package]]
+name = "rustc_ast_lowering"
+version = "0.0.0"
+dependencies = [
+ "log",
+ "rustc",
+ "rustc_data_structures",
+ "rustc_error_codes",
+ "rustc_errors",
+ "rustc_index",
+ "rustc_span",
+ "rustc_target",
+ "smallvec 1.0.0",
+ "syntax",
+]
+
 [[package]]
 name = "rustc_builtin_macros"
 version = "0.0.0"
@@ -3578,6 +3594,7 @@ dependencies = [
  "once_cell",
  "rustc",
  "rustc-rayon",
+ "rustc_ast_lowering",
  "rustc_builtin_macros",
  "rustc_codegen_llvm",
  "rustc_codegen_ssa",
@@ -3783,6 +3800,7 @@ dependencies = [
  "bitflags",
  "log",
  "rustc",
+ "rustc_ast_lowering",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_errors",

src/libcore/lib.rs

@@ -76,6 +76,7 @@
 #![feature(const_fn_union)]
 #![feature(const_generics)]
 #![feature(const_ptr_offset_from)]
+#![feature(const_result)]
 #![feature(const_type_name)]
 #![feature(custom_inner_attributes)]
 #![feature(decl_macro)]