Remove Expr::MatchPattern (#11367)

# Description
Following from #11356, it looks like `Expr::MatchPattern` is no longer
used in any way. This PR removes `Expr::MatchPattern` alongside
`Type::MatchPattern` and `SyntaxShape::MatchPattern`.

# User-Facing Changes
Breaking API change for `nu_protocol`.

crates/nu-protocol/src/ast/expr.rs

@@ -44,7 +44,6 @@ pub enum Expr {
     Overlay(Option<BlockId>), // block ID of the overlay's origin module
     Signature(Box<Signature>),
     StringInterpolation(Vec<Expression>),
-    MatchPattern(Box<MatchPattern>),
     Spread(Box<Expression>),
     Nothing,
     Garbage,

crates/nu-protocol/src/ast/expression.rs

@@ -221,7 +221,6 @@ impl Expression {
                 }
                 false
             }
-            Expr::MatchPattern(_) => false,
             Expr::Operator(_) => false,
             Expr::MatchBlock(_) => false,
             Expr::Range(left, middle, right, ..) => {
@@ -407,7 +406,6 @@ impl Expression {
             Expr::Nothing => {}
             Expr::GlobPattern(_) => {}
             Expr::Int(_) => {}
-            Expr::MatchPattern(_) => {}
             Expr::MatchBlock(_) => {}
             Expr::Keyword(_, _, expr) => expr.replace_in_variable(working_set, new_var_id),
             Expr::List(list) => {
@@ -576,7 +574,6 @@ impl Expression {
             Expr::Garbage => {}
             Expr::Nothing => {}
             Expr::GlobPattern(_) => {}
-            Expr::MatchPattern(_) => {}
             Expr::MatchBlock(_) => {}
             Expr::Int(_) => {}
             Expr::Keyword(_, _, expr) => expr.replace_span(working_set, replaced, new_span),

crates/nu-protocol/src/eval_base.rs

@@ -277,8 +277,7 @@ pub trait Eval {
             Expr::GlobPattern(pattern) => {
                 Self::eval_glob_pattern(state, mut_state, pattern.clone(), expr.span)
             }
-            Expr::MatchPattern(_) // match patterns are handled directly by commands
-            | Expr::MatchBlock(_) // match blocks are handled by `match`
+            Expr::MatchBlock(_) // match blocks are handled by `match`
             | Expr::VarDecl(_)
             | Expr::ImportPattern(_)
             | Expr::Signature(_)

crates/nu-protocol/src/syntax_shape.rs

@@ -82,9 +82,6 @@ pub enum SyntaxShape {
     /// A block of matches, used by `match`
     MatchBlock,
 
-    /// A match pattern, eg `{a: $foo}`
-    MatchPattern,
-
     /// Nothing
     Nothing,
 
@@ -163,7 +160,6 @@ impl SyntaxShape {
             }
             SyntaxShape::Keyword(_, expr) => expr.to_type(),
             SyntaxShape::MatchBlock => Type::Any,
-            SyntaxShape::MatchPattern => Type::Any,
             SyntaxShape::MathExpression => Type::Any,
             SyntaxShape::Nothing => Type::Nothing,
             SyntaxShape::Number => Type::Number,
@@ -240,7 +236,6 @@ impl Display for SyntaxShape {
             SyntaxShape::MathExpression => write!(f, "variable"),
             SyntaxShape::VarWithOptType => write!(f, "vardecl"),
             SyntaxShape::Signature => write!(f, "signature"),
-            SyntaxShape::MatchPattern => write!(f, "match-pattern"),
             SyntaxShape::MatchBlock => write!(f, "match-block"),
             SyntaxShape::Expression => write!(f, "expression"),
             SyntaxShape::Boolean => write!(f, "bool"),

crates/nu-protocol/src/ty.rs

@@ -24,7 +24,6 @@ pub enum Type {
     Int,
     List(Box<Type>),
     ListStream,
-    MatchPattern,
     #[default]
     Nothing,
     Number,
@@ -110,7 +109,6 @@ impl Type {
             Type::Binary => SyntaxShape::Binary,
             Type::Custom(_) => SyntaxShape::Any,
             Type::Signature => SyntaxShape::Signature,
-            Type::MatchPattern => SyntaxShape::MatchPattern,
         }
     }
 
@@ -131,7 +129,6 @@ impl Type {
             Type::Record(_) => String::from("record"),
             Type::Table(_) => String::from("table"),
             Type::List(_) => String::from("list"),
-            Type::MatchPattern => String::from("match-pattern"),
             Type::Nothing => String::from("nothing"),
             Type::Number => String::from("number"),
             Type::String => String::from("string"),
@@ -198,7 +195,6 @@ impl Display for Type {
             Type::Binary => write!(f, "binary"),
             Type::Custom(custom) => write!(f, "{custom}"),
             Type::Signature => write!(f, "signature"),
-            Type::MatchPattern => write!(f, "match-pattern"),
         }
     }
 }