diff --git a/src/attributes.md b/src/attributes.md
index d6cbed613..887d184c9 100644
--- a/src/attributes.md
+++ b/src/attributes.md
@@ -116,9 +116,10 @@ attributes]. It has the following grammar:
 r[attributes.meta.syntax]
 ```grammar,attributes
 MetaItem ->
-      SimplePath
-    | SimplePath `=` Expression
-    | SimplePath `(` MetaSeq? `)`
+    SimplePath (
+        `=` Expression
+      | `(` MetaSeq? `)`
+    )?
 
 MetaSeq ->
     MetaItemInner ( `,` MetaItemInner )* `,`?
diff --git a/src/comments.md b/src/comments.md
index 8ffa56551..c77e8b1d4 100644
--- a/src/comments.md
+++ b/src/comments.md
@@ -4,8 +4,7 @@ r[comments]
 r[comments.syntax]
 ```grammar,lexer
 @root LINE_COMMENT ->
-      `//` (~[`/` `!` LF] | `//`) ~LF*
-    | `//`
+    `//` ( ( ~[`/` `!` LF] | `//` ) ~LF* )?
 
 BLOCK_COMMENT ->
       `/*`
diff --git a/src/expressions/array-expr.md b/src/expressions/array-expr.md
index 04374f3f3..622505f1a 100644
--- a/src/expressions/array-expr.md
+++ b/src/expressions/array-expr.md
@@ -8,8 +8,10 @@ r[expr.array.syntax]
 ArrayExpression -> `[` ArrayElements? `]`
 
 ArrayElements ->
-      Expression ( `,` Expression )* `,`?
-    | Expression `;` Expression
+    Expression (
+        ( `,` Expression )* `,`?
+      | `;` Expression
+    )
 ```
 
 r[expr.array.constructor]
diff --git a/src/expressions/block-expr.md b/src/expressions/block-expr.md
index da0f93b36..489d177c7 100644
--- a/src/expressions/block-expr.md
+++ b/src/expressions/block-expr.md
@@ -10,8 +10,7 @@ BlockExpression ->
     `}`
 
 Statements ->
-      Statement+
-    | Statement+ ExpressionWithoutBlock
+      Statement+ ExpressionWithoutBlock?
     | ExpressionWithoutBlock
 ```
 
diff --git a/src/expressions/operator-expr.md b/src/expressions/operator-expr.md
index 5151bd2c6..88d714918 100644
--- a/src/expressions/operator-expr.md
+++ b/src/expressions/operator-expr.md
@@ -58,10 +58,9 @@ r[expr.operator.borrow]
 r[expr.operator.borrow.syntax]
 ```grammar,expressions
 BorrowExpression ->
-      (`&`|`&&`) Expression
-    | (`&`|`&&`) `mut` Expression
-    | (`&`|`&&`) `raw` `const` Expression
-    | (`&`|`&&`) `raw` `mut` Expression
+    ( `&` | `&&` )
+    ( `mut` | `raw` ( `const` | `mut` ) )?
+    Expression
 ```
 
 r[expr.operator.borrow.intro]
@@ -257,8 +256,7 @@ r[expr.negate]
 r[expr.negate.syntax]
 ```grammar,expressions
 NegationExpression ->
-      `-` Expression
-    | `!` Expression
+    ( `-` | `!`)  Expression
 ```
 
 r[expr.negate.intro]
@@ -291,16 +289,9 @@ r[expr.arith-logic]
 r[expr.arith-logic.syntax]
 ```grammar,expressions
 ArithmeticOrLogicalExpression ->
-      Expression `+` Expression
-    | Expression `-` Expression
-    | Expression `*` Expression
-    | Expression `/` Expression
-    | Expression `%` Expression
-    | Expression `&` Expression
-    | Expression `|` Expression
-    | Expression `^` Expression
-    | Expression `<<` Expression
-    | Expression `>>` Expression
+    Expression (
+        `+` | `-` | `*` | `/` | `%` | `&` | `|` | `^` | `<<` | `>>`
+    ) Expression
 ```
 
 r[expr.arith-logic.intro]
@@ -354,12 +345,9 @@ r[expr.cmp]
 r[expr.cmp.syntax]
 ```grammar,expressions
 ComparisonExpression ->
-      Expression `==` Expression
-    | Expression `!=` Expression
-    | Expression `>` Expression
-    | Expression `<` Expression
-    | Expression `>=` Expression
-    | Expression `<=` Expression
+    Expression (
+        `==` | `!=` | `>` | `<` | `>=` | `<=`
+    ) Expression
 ```
 
 r[expr.cmp.intro]
@@ -413,8 +401,7 @@ r[expr.bool-logic]
 r[expr.bool-logic.syntax]
 ```grammar,expressions
 LazyBooleanExpression ->
-      Expression `||` Expression
-    | Expression `&&` Expression
+    Expression (`||` | `&&`) Expression
 ```
 
 r[expr.bool-logic.intro]
@@ -809,16 +796,11 @@ r[expr.compound-assign]
 r[expr.compound-assign.syntax]
 ```grammar,expressions
 CompoundAssignmentExpression ->
-      Expression `+=` Expression
-    | Expression `-=` Expression
-    | Expression `*=` Expression
-    | Expression `/=` Expression
-    | Expression `%=` Expression
-    | Expression `&=` Expression
-    | Expression `|=` Expression
-    | Expression `^=` Expression
-    | Expression `<<=` Expression
-    | Expression `>>=` Expression
+    Expression (
+        `+=` | `-=` | `*=` | `/=` | `%=`
+      | `&=` | `|=` | `^=`
+      | `<<=` | `>>=`
+    ) Expression
 ```
 
 r[expr.compound-assign.intro]
diff --git a/src/inline-assembly.md b/src/inline-assembly.md
index f1d19974b..33a8bfcce 100644
--- a/src/inline-assembly.md
+++ b/src/inline-assembly.md
@@ -73,20 +73,21 @@ AsmOption ->
     | `att_syntax`
     | `raw`
 
-RegOperand -> (ParamName `=`)?
-    (
-          DirSpec `(` RegSpec `)` Expression
-        | DualDirSpec `(` RegSpec `)` DualDirSpecExpression
-        | `sym` PathExpression
-        | `const` Expression
-        | `label` `{` Statements? `}`
+RegOperand ->
+    (ParamName `=`)? (
+        (
+            DirSpec `(` RegSpec `)`
+          | `const`
+        ) Expression
+      | DualDirSpec `(` RegSpec `)` DualDirSpecExpression
+      | `sym` PathExpression
+      | `label` `{` Statements? `}`
     )
 
 ParamName -> IDENTIFIER_OR_KEYWORD | RAW_IDENTIFIER
 
 DualDirSpecExpression ->
-      Expression
-    | Expression `=>` Expression
+    Expression ( `=>` Expression )?
 
 RegSpec -> RegisterClass | ExplicitRegister
 
diff --git a/src/items/external-blocks.md b/src/items/external-blocks.md
index 0053969a1..4bd9e0150 100644
--- a/src/items/external-blocks.md
+++ b/src/items/external-blocks.md
@@ -11,9 +11,8 @@ ExternBlock ->
 
 ExternalItem ->
     OuterAttribute* (
-        MacroInvocationSemi
-      | Visibility? StaticItem
-      | Visibility? Function
+        Visibility? ( StaticItem | Function )
+      | MacroInvocationSemi
     )
 ```
 
diff --git a/src/items/functions.md b/src/items/functions.md
index 806cacf04..873e2a2a2 100644
--- a/src/items/functions.md
+++ b/src/items/functions.md
@@ -16,15 +16,17 @@ ItemSafety -> `safe`[^extern-safe] | `unsafe`
 Abi -> STRING_LITERAL | RAW_STRING_LITERAL
 
 FunctionParameters ->
-      SelfParam `,`?
-    | (SelfParam `,`)? FunctionParam (`,` FunctionParam)* `,`?
+      SelfParam ( `,` FunctionParams? )?
+    | FunctionParams
 
 SelfParam -> OuterAttribute* ( ShorthandSelf | TypedSelf )
 
-ShorthandSelf -> (`&` | `&` Lifetime)? `mut`? `self`
+ShorthandSelf -> ( `&` Lifetime? )? `mut`? `self`
 
 TypedSelf -> `mut`? `self` `:` Type
 
+FunctionParams -> FunctionParam ( `,` FunctionParam )* `,`?
+
 FunctionParam -> OuterAttribute* ( FunctionParamPattern | `...` | Type[^fn-param-2015] )
 
 FunctionParamPattern -> PatternNoTopAlt `:` ( Type | `...` )
diff --git a/src/items/modules.md b/src/items/modules.md
index 295d1d7b5..7d7d1dccb 100644
--- a/src/items/modules.md
+++ b/src/items/modules.md
@@ -4,11 +4,10 @@ r[items.mod]
 r[items.mod.syntax]
 ```grammar,items
 Module ->
-      `unsafe`? `mod` IDENTIFIER `;`
-    | `unsafe`? `mod` IDENTIFIER `{`
-        InnerAttribute*
-        Item*
-      `}`
+    `unsafe`? `mod` IDENTIFIER (
+        `{` InnerAttribute* Item* `}`
+      | `;`
+    )
 ```
 
 r[items.mod.intro]
diff --git a/src/items/use-declarations.md b/src/items/use-declarations.md
index ec993d737..c1f5dbb8d 100644
--- a/src/items/use-declarations.md
+++ b/src/items/use-declarations.md
@@ -6,8 +6,10 @@ r[items.use.syntax]
 UseDeclaration -> `use` UseTree `;`
 
 UseTree ->
-      (SimplePath? `::`)? `*`
-    | (SimplePath? `::`)? `{` (UseTree ( `,`  UseTree )* `,`?)? `}`
+      ( SimplePath? `::` )? (
+          `{` ( UseTree ( `,`  UseTree )* `,`? )? `}`
+        | `*`
+      )
     | SimplePath ( `as` ( IDENTIFIER | `_` ) )?
 ```
 
diff --git a/src/macros-by-example.md b/src/macros-by-example.md
index 9bdb93fce..f8c822d4b 100644
--- a/src/macros-by-example.md
+++ b/src/macros-by-example.md
@@ -7,8 +7,10 @@ MacroRulesDefinition ->
     `macro_rules` `!` IDENTIFIER MacroRulesDef
 
 MacroRulesDef ->
-      `(` MacroRules `)` `;`
-    | `[` MacroRules `]` `;`
+      (
+          `(` MacroRules `)`
+        | `[` MacroRules `]`
+      ) `;`
     | `{` MacroRules `}`
 
 MacroRules ->
@@ -25,8 +27,11 @@ MacroMatcher ->
 MacroMatch ->
       Token _except `$` and [delimiters][lex.token.delim]_
     | MacroMatcher
-    | `$` ( IDENTIFIER_OR_KEYWORD _except `crate`_ | RAW_IDENTIFIER | `_` ) `:` MacroFragSpec
-    | `$` `(` MacroMatch+ `)` MacroRepSep? MacroRepOp
+    | `$` (
+          ( IDENTIFIER_OR_KEYWORD _except `crate`_ | RAW_IDENTIFIER | `_` )
+          `:` MacroFragSpec
+        | `(` MacroMatch+ `)` MacroRepSep? MacroRepOp
+      )
 
 MacroFragSpec ->
       `block` | `expr` | `expr_2021` | `ident` | `item` | `lifetime` | `literal`
diff --git a/src/macros.md b/src/macros.md
index 48555fb25..1e2073ee4 100644
--- a/src/macros.md
+++ b/src/macros.md
@@ -29,9 +29,13 @@ TokenTree ->
     Token _except [delimiters][lex.token.delim]_ | DelimTokenTree
 
 MacroInvocationSemi ->
-      SimplePath `!` `(` TokenTree* `)` `;`
-    | SimplePath `!` `[` TokenTree* `]` `;`
-    | SimplePath `!` `{` TokenTree* `}`
+    SimplePath `!` (
+        (
+            `(` TokenTree* `)`
+          | `[` TokenTree* `]`
+        ) `;`
+      | `{` TokenTree* `}`
+    )
 ```
 
 r[macro.invocation.intro]
diff --git a/src/paths.md b/src/paths.md
index afa5b82ec..e5ef466bc 100644
--- a/src/paths.md
+++ b/src/paths.md
@@ -54,16 +54,14 @@ PathIdentSegment ->
     IDENTIFIER | `super` | `self` | `Self` | `crate` | `$crate`
 
 GenericArgs ->
-      `<` `>`
-    | `<` ( GenericArg `,` )* GenericArg `,`? `>`
+    `<` ( GenericArg ( `,` GenericArg )* `,`? )? `>`
 
 GenericArg ->
     Lifetime | Type | GenericArgsConst | GenericArgsBinding | GenericArgsBounds
 
 GenericArgsConst ->
       BlockExpression
-    | LiteralExpression
-    | `-` LiteralExpression
+    | `-`? LiteralExpression
     | SimplePathSegment
 
 GenericArgsBinding ->
diff --git a/src/patterns.md b/src/patterns.md
index 2d9ddb5ac..ef51b974d 100644
--- a/src/patterns.md
+++ b/src/patterns.md
@@ -149,8 +149,7 @@ LiteralPattern ->
     | RAW_BYTE_STRING_LITERAL
     | C_STRING_LITERAL
     | RAW_C_STRING_LITERAL
-    | `-`? INTEGER_LITERAL
-    | `-`? FLOAT_LITERAL
+    | `-`? ( INTEGER_LITERAL | FLOAT_LITERAL )
 ```
 
 r[patterns.literal.intro]
@@ -499,8 +498,7 @@ ObsoleteRangePattern ->
 RangePatternBound ->
       CHAR_LITERAL
     | BYTE_LITERAL
-    | `-`? INTEGER_LITERAL
-    | `-`? FLOAT_LITERAL
+    | `-`? ( INTEGER_LITERAL | FLOAT_LITERAL )
     | PathExpression
 ```
 
@@ -708,7 +706,7 @@ StructPattern ->
     `}`
 
 StructPatternElements ->
-      StructPatternFields (`,` | `,` StructPatternEtCetera)?
+      StructPatternFields ( `,` StructPatternEtCetera? )?
     | StructPatternEtCetera
 
 StructPatternFields ->
@@ -717,8 +715,7 @@ StructPatternFields ->
 StructPatternField ->
     OuterAttribute*
     (
-        TUPLE_INDEX `:` Pattern
-      | IDENTIFIER `:` Pattern
+        ( TUPLE_INDEX | IDENTIFIER ) `:` Pattern
       | `ref`? `mut`? IDENTIFIER
     )
 
@@ -837,9 +834,8 @@ r[patterns.tuple.syntax]
 TuplePattern -> `(` TuplePatternItems? `)`
 
 TuplePatternItems ->
-      Pattern `,`
+      Pattern ( `,` | ( `,` Pattern )+ `,`? )
     | RestPattern
-    | Pattern (`,` Pattern)+ `,`?
 ```
 
 r[patterns.tuple.intro]
diff --git a/src/statements.md b/src/statements.md
index 8b10f0971..fe0c4ce5c 100644
--- a/src/statements.md
+++ b/src/statements.md
@@ -61,8 +61,11 @@ r[statement.let.syntax]
 LetStatement ->
     OuterAttribute* `let` PatternNoTopAlt ( `:` Type )?
     (
-          `=` Expression
-        | `=` Expression _except [LazyBooleanExpression] or end with a `}`_ `else` BlockExpression
+        `=` (
+            Expression _except [LazyBooleanExpression] or end with a `}`_
+            `else` BlockExpression
+          | Expression
+        )
     )? `;`
 ```
 
diff --git a/src/tokens.md b/src/tokens.md
index 294753e69..4f0675df1 100644
--- a/src/tokens.md
+++ b/src/tokens.md
@@ -657,9 +657,11 @@ r[lex.token.literal.float]
 r[lex.token.literal.float.syntax]
 ```grammar,lexer
 FLOAT_LITERAL ->
-      DEC_LITERAL `.` _not immediately followed by `.`, `_` or an XID_Start character_
-    | DEC_LITERAL `.` DEC_LITERAL SUFFIX_NO_E?
-    | DEC_LITERAL (`.` DEC_LITERAL)? FLOAT_EXPONENT SUFFIX?
+    DEC_LITERAL (
+        `.` _not immediately followed by `.`, `_` or an XID_Start character_
+      | `.` DEC_LITERAL ( SUFFIX_NO_E? | FLOAT_EXPONENT SUFFIX? )
+      | FLOAT_EXPONENT SUFFIX?
+    )
 
 FLOAT_EXPONENT ->
     (`e`|`E`) (`+`|`-`)? (DEC_DIGIT|`_`)* DEC_DIGIT (DEC_DIGIT|`_`)*
@@ -714,8 +716,11 @@ r[lex.token.literal.reserved.syntax]
 RESERVED_NUMBER ->
       BIN_LITERAL [`2`-`9`]
     | OCT_LITERAL [`8`-`9`]
-    | ( BIN_LITERAL | OCT_LITERAL | HEX_LITERAL ) `.` _not immediately followed by `.`, `_` or an XID_Start character_
-    | ( BIN_LITERAL | OCT_LITERAL ) (`e`|`E`)
+    | ( BIN_LITERAL | OCT_LITERAL ) (
+          `.` _not immediately followed by `.`, `_` or an XID_Start character_
+        | (`e`|`E`)
+      )
+    | HEX_LITERAL `.` _not immediately followed by `.`, `_` or an XID_Start character_
     | `0b` `_`* <end of input or not BIN_DIGIT>
     | `0o` `_`* <end of input or not OCT_DIGIT>
     | `0x` `_`* <end of input or not HEX_DIGIT>
diff --git a/src/trait-bounds.md b/src/trait-bounds.md
index f31265fbc..ffaa4b849 100644
--- a/src/trait-bounds.md
+++ b/src/trait-bounds.md
@@ -7,9 +7,9 @@ TypeParamBounds -> TypeParamBound ( `+` TypeParamBound )* `+`?
 
 TypeParamBound -> Lifetime | TraitBound | UseBound
 
-TraitBound ->
-      ( `?` | ForLifetimes )? TypePath
-    | `(` ( `?` | ForLifetimes )? TypePath `)`
+TraitBound -> `(` TraitBoundNoParens `)` | TraitBoundNoParens
+
+TraitBoundNoParens ->  ( `?` | ForLifetimes )? TypePath
 
 LifetimeBounds -> ( Lifetime `+` )* Lifetime?
 
@@ -21,8 +21,7 @@ Lifetime ->
 UseBound -> `use` UseBoundGenericArgs
 
 UseBoundGenericArgs ->
-      `<` `>`
-    | `<` ( UseBoundGenericArg `,`)* UseBoundGenericArg `,`? `>`
+    `<` ( UseBoundGenericArg ( `,` UseBoundGenericArg )*  `,`? )? `>`
 
 UseBoundGenericArg ->
       Lifetime
diff --git a/src/types/function-pointer.md b/src/types/function-pointer.md
index 03c879366..b69c5ed30 100644
--- a/src/types/function-pointer.md
+++ b/src/types/function-pointer.md
@@ -21,7 +21,7 @@ MaybeNamedParam ->
     OuterAttribute* ( ( IDENTIFIER | `_` ) `:` )? Type
 
 MaybeNamedFunctionParametersVariadic ->
-    ( MaybeNamedParam `,` )* MaybeNamedParam `,` OuterAttribute* `...`
+    MaybeNamedParam ( `,` MaybeNamedParam )* `,` OuterAttribute* `...`
 ```
 
 r[type.fn-pointer.intro]
diff --git a/src/types/tuple.md b/src/types/tuple.md
index a686cfb8f..51a2643b7 100644
--- a/src/types/tuple.md
+++ b/src/types/tuple.md
@@ -4,8 +4,7 @@ r[type.tuple]
 r[type.tuple.syntax]
 ```grammar,types
 TupleType ->
-      `(` `)`
-    | `(` ( Type `,` )+ Type? `)`
+    `(` ( ( Type `,` )+ Type? )? `)`
 ```
 
 r[type.tuple.intro]
diff --git a/src/visibility-and-privacy.md b/src/visibility-and-privacy.md
index 847d46977..e39ed5c81 100644
--- a/src/visibility-and-privacy.md
+++ b/src/visibility-and-privacy.md
@@ -4,11 +4,14 @@ r[vis]
 r[vis.syntax]
 ```grammar,items
 Visibility ->
-      `pub`
-    | `pub` `(` `crate` `)`
-    | `pub` `(` `self` `)`
-    | `pub` `(` `super` `)`
-    | `pub` `(` `in` SimplePath `)`
+    `pub` (
+      `(` (
+          `crate`
+        | `self`
+        | `super`
+        | `in` SimplePath
+      ) `)`
+    )?
 ```
 
 r[vis.intro]