Remove tagging in grammar. See msg.

Turns out Pest has a bug (see
pest-parser/pest#875) where it fails to detect
left-recursion when tags are used.

If we remove all the tags, then it is able to successfully detect left
recursion better.

This commit removes the tags, and also fixes up one instance of
left-recursion.

We still have the badly left-recursive `bin_expr` to fix up, but that is
left for another commit.

src/verus.pest

@@ -237,8 +237,8 @@ macro_rules = {
 
 macro_def = {
     attr* ~ visibility? ~
-    "macro" ~ name ~ #args=token_tree? ~
-    #body=token_tree
+    "macro" ~ name ~ token_tree? ~
+    token_tree
 }
 
 module = {
@@ -376,13 +376,13 @@ const = {
     attr* ~ visibility? ~
     "default"? ~
     "const" ~ (name | "_") ~ ":" ~ type ~
-    ("=" ~ #body=expr)? ~ ";"
+    ("=" ~ expr)? ~ ";"
 }
 
 static = {
     attr* ~ visibility? ~
     "static" ~ "mut"? ~ name ~ ":" ~ type ~
-    ("=" ~ #body=expr)? ~ ";"
+    ("=" ~ expr)? ~ ";"
 }
 
 trait = {
@@ -411,7 +411,7 @@ assoc_item = {
 impl = {
     attr* ~ visibility? ~
     "default"? ~ "unsafe"? ~
-    "impl" ~ generic_param_list? ~ ("const"? ~ "!"? ~ #trait=type ~ "for")? ~ #self_ty=type ~ where_clause? ~
+    "impl" ~ generic_param_list? ~ ("const"? ~ "!"? ~ type ~ "for")? ~ type ~ where_clause? ~
     assoc_item_list
 }
 
@@ -442,12 +442,12 @@ generic_param = {
 
 type_param = {
     attr* ~ name ~ (":" ~ type_bound_list)? ~
-    ("=" ~ #default_type=type)?
+    ("=" ~ type)?
 }
 
 const_param = {
     attr* ~ "const" ~ name ~ ":" ~ type ~
-    ("=" ~ #default_val=expr)?
+    ("=" ~ expr)?
 }
 
 lifetime_param = {
@@ -487,7 +487,7 @@ stmt = {
 
 let_stmt = {
     attr* ~ "let" ~ "ghost"? ~ "tracked"? ~ pat ~ (":" ~ type)? ~
-    "=" ~ #initializer=expr ~
+    "=" ~ expr ~
     let_else? ~
     ";"
 }
@@ -515,6 +515,8 @@ expr = {
       | "@"
         // index_expr
       | "[" ~ expr ~ "]"
+        // method_call_expr
+      | "." ~ name_ref ~ generic_arg_list? ~ arg_list
     )*
 }
 
@@ -532,7 +534,6 @@ expr_inner = {
   | loop_expr
   | macro_call
   | match_expr
-  | method_call_expr
   | paren_expr
   | path_expr
   | prefix_expr
@@ -556,7 +557,7 @@ macro_expr = {
 }
 
 literal = {
-    attr* ~ #value=(
+    attr* ~ (
         int_number
       | float_number
       | string
@@ -577,8 +578,8 @@ path_expr = {
 stmt_list = {
     "{" ~
     attr* ~
-    #statements=stmt* ~
-    #tail_expr=expr? ~
+    stmt* ~
+    expr? ~
     "}"
 }
 
@@ -591,20 +592,20 @@ block_expr = {
 }
 
 prefix_expr = {
-    attr* ~ #op=("-" | "!" | "*" | "&&&" | "|||") ~ expr
+    attr* ~ ("-" | "!" | "*" | "&&&" | "|||") ~ expr
 }
 
 bin_expr = {
     attr* ~
-    #lhs=expr ~
-    #op=(
+    expr ~
+    (
         "||" | "&&"
       | "==" | "!=" | "<=" | ">=" | "<" | ">"
       | "+" | "*" | "-" | "/" | "%" | "<<" | ">>" | "^" | "|" | "&"
       | "=" | "+=" | "/=" | "*=" | "%=" | ">>=" | "<<=" | "-=" | "|=" | "&=" | "^="
       | "==>"
     ) ~
-    #rhs=expr
+    expr
 }
 
 paren_expr = {
@@ -619,7 +620,7 @@ array_expr = {
 }
 
 tuple_expr = {
-    attr* ~ "(" ~ attr* ~ #fields=(expr ~ ("," ~ expr)* ~ ","?)? ~ ")"
+    attr* ~ "(" ~ attr* ~ (expr ~ ("," ~ expr)* ~ ","?)? ~ ")"
 }
 
 record_expr = {
@@ -629,8 +630,8 @@ record_expr = {
 record_expr_field_list = {
     "{" ~
     attr* ~
-    #fields=(record_expr_field ~ ("," ~ record_expr_field)* ~ ","?)? ~
-    (".." ~ #spread=expr)? ~
+    (record_expr_field ~ ("," ~ record_expr_field)* ~ ","?)? ~
+    (".." ~ expr)? ~
     "}"
 }
 
@@ -639,37 +640,33 @@ record_expr_field = {
 }
 
 arg_list = {
-    "(" ~ #args=(expr ~ ("," ~ expr)* ~ ","?)? ~ ")"
-}
-
-method_call_expr = {
-    attr* ~ #receiver=expr ~ "." ~ name_ref ~ generic_arg_list? ~ arg_list
+    "(" ~ (expr ~ ("," ~ expr)* ~ ","?)? ~ ")"
 }
 
 closure_expr = {
     attr* ~ ("for" ~ generic_param_list)? ~
     "const"? ~ "static"? ~ "async"? ~ "move" ~ "forall"? ~ "exists"? ~
     param_list ~ ret_type? ~ attr* ~
-    #body=expr
+    expr
 }
 
 if_expr = {
-    attr* ~ "if" ~ #condition=expr ~ #then_branch=block_expr ~
-    ("else" ~ #else_branch=(if_expr | block_expr))?
+    attr* ~ "if" ~ expr ~ block_expr ~
+    ("else" ~ (if_expr | block_expr))?
 }
 
 loop_expr = {
-    attr* ~ label? ~ "loop" ~ #loop_body=block_expr
+    attr* ~ label? ~ "loop" ~ block_expr
 }
 
 for_expr = {
-    attr* ~ label? ~ "for" ~ pat ~ "in" ~ #iterable=expr ~
-    #loop_body=block_expr
+    attr* ~ label? ~ "for" ~ pat ~ "in" ~ expr ~
+    block_expr
 }
 
 while_expr = {
-    attr* ~ label? ~ "while" ~ #condition=expr ~ invariant_clause? ~ decreases_clause? ~
-    #loop_body=block_expr
+    attr* ~ label? ~ "while" ~ expr ~ invariant_clause? ~ decreases_clause? ~
+    block_expr
 }
 
 label = {
@@ -685,7 +682,7 @@ continue_expr = {
 }
 
 range_expr = {
-    attr* ~ #start=expr? ~ #op=(".." | "..=") ~ #end=expr?
+    attr* ~ expr? ~ (".." | "..=") ~ expr?
 }
 
 match_expr = {
@@ -695,12 +692,12 @@ match_expr = {
 match_arm_list = {
     "{" ~
     attr* ~
-    #arms=match_arm* ~
+    match_arm* ~
     "}"
 }
 
 match_arm = {
-    attr* ~ pat ~ #guard=match_guard? ~ "=>" ~ expr ~ ","?
+    attr* ~ pat ~ match_guard? ~ "=>" ~ expr ~ ","?
 }
 
 match_guard = {
@@ -823,7 +820,12 @@ type_bound = {
 
 
 pat = {
-    pat_inner ~ ("|" ~ pat_inner)* ~ "|"?
+    pat_inner ~ (
+        // range_pat (for 1.. or 1..2)
+        ("..=" | "..") ~ pat?
+        // or_pat
+      | ("|" ~ pat_inner)* ~ "|"?
+    )?
 }
 
 pat_inner = {
@@ -835,7 +837,7 @@ pat_inner = {
   | paren_pat
   | path_pat
   | wildcard_pat
-  | range_pat
+  | end_only_range_pat
   | record_pat
   | ref_pat
   | slice_pat
@@ -856,13 +858,8 @@ wildcard_pat = {
     "_"
 }
 
-range_pat = {
-    // 1..
-    #start=pat ~ #op=(".." | "..=")
-    // 1..2
-  | #start=pat ~ #op=(".." | "..=") ~ #end=pat
-    // ..2
-  | #op=(".." | "..=") ~ #end=pat
+end_only_range_pat = {
+    ("..=" | "..") ~ pat
 }
 
 ref_pat = {