Update with slice pattern restrictions

Author: workingjubilee

src/patterns.md

@@ -10,7 +10,6 @@
 >    | [_IdentifierPattern_]\
 >    | [_WildcardPattern_]\
 >    | [_RestPattern_]\
->    | [_ObsoleteRangePattern_]\
 >    | [_ReferencePattern_]\
 >    | [_StructPattern_]\
 >    | [_TupleStructPattern_]\
@@ -401,7 +400,14 @@ match tuple {
 
 > **<sup>Syntax</sup>**\
 > _RangePattern_ :\
-> &nbsp;&nbsp; &nbsp;&nbsp; _RangePatternBound_ `..=` _RangePatternBound_\
+> &nbsp;&nbsp; &nbsp;&nbsp; _InclusiveRangePattern_\
+> &nbsp;&nbsp; | _HalfOpenRangePattern_\
+> &nbsp;&nbsp; | _ObsoleteRangePattern_
+
+> _InclusiveRangePattern_ :\
+> &nbsp;&nbsp; &nbsp;&nbsp; _RangePatternBound_ `..=` _RangePatternBound_
+>
+> _HalfOpenRangePattern_ :\
 > &nbsp;&nbsp; | _RangePatternBound_ `..`
 >
 > _ObsoleteRangePattern_ :\
@@ -421,12 +427,14 @@ it matches all the values between and including both of its bounds. A range patt
 half-open is written with a lower bound but not an upper bound, and matches any value equal to
 or greater than the specified lower bound.
 
-For example, a pattern `'m'..='p'` will match only the values `'m'`, `'n'`, `'o'`, and `'p'`. The
+For example, a pattern `'m'..='p'` will match only the values `'m'`, `'n'`, `'o'`, and `'p'`. For an integer the
 pattern `1..` will match 9, or 9001, or 9007199254740991 (if it is of an appropriate size), but
-not 0 or negative numbers for signed integers. The bounds can be literals or paths that point
+not 0, and not negative numbers for signed integers. The bounds can be literals or paths that point
 to constant values.
 
-A pattern a `..=` b must always have a &le; b. It is an error to have a range pattern
+A half-open range pattern in the style `a..` cannot be used to match within the context of a slice.
+
+A pattern `a..=b` must always have a &le; b. It is an error to have a range pattern
 `10..=0`, for example.
 
 The `...` syntax is kept for backwards compatibility.
@@ -708,7 +716,11 @@ match int_reference {
 > &nbsp;&nbsp; `[` _SlicePatternItems_<sup>?</sup> `]`
 >
 > _SlicePatternItems_ :\
-> &nbsp;&nbsp; [_Pattern_] \(`,` [_Pattern_])<sup>\*</sup> `,`<sup>?</sup>
+> &nbsp;&nbsp; [_InSlicePattern_] \(`,` [_InSlicePattern_])<sup>\*</sup> `,`<sup>?</sup>
+>
+> _InSlicePattern_ :\
+> &nbsp;&nbsp; &nbsp;&nbsp; _PatternWithoutRange_\
+> &nbsp;&nbsp; | [_ClosedRangePattern_]
 
 Slice patterns can match both arrays of fixed size and slices of dynamic size.
 ```rust
@@ -762,6 +774,7 @@ refer to refutable constants or enum variants for enums with multiple variants.
 
 [_GroupedPattern_]: #grouped-patterns
 [_IdentifierPattern_]: #identifier-patterns
+[_InSlicePattern_]: #slice-patterns
 [_LiteralPattern_]: #literal-patterns
 [_MacroInvocation_]: macros.md#macro-invocation
 [_ObsoleteRangePattern_]: #range-patterns
@@ -771,6 +784,7 @@ refer to refutable constants or enum variants for enums with multiple variants.
 [_PatternWithoutRange_]: #patterns
 [_QualifiedPathInExpression_]: paths.md#qualified-paths
 [_RangePattern_]: #range-patterns
+[_ClosedRangePattern_]: #range-patterns
 [_ReferencePattern_]: #reference-patterns
 [_RestPattern_]: #rest-patterns
 [_SlicePattern_]: #slice-patterns