Fix handling of literal patterns

Wrap them in a LiteralPat node so they can be distinguished from literal
expressions.

crates/ra_syntax/src/ast/generated.rs

@@ -1821,6 +1821,38 @@ impl LiteralExpr {
 
 impl LiteralExpr {}
 
+// LiteralPat
+#[derive(Debug, PartialEq, Eq, Hash)]
+#[repr(transparent)]
+pub struct LiteralPat {
+    pub(crate) syntax: SyntaxNode,
+}
+unsafe impl TransparentNewType for LiteralPat {
+    type Repr = rowan::SyntaxNode<RaTypes>;
+}
+
+impl AstNode for LiteralPat {
+    fn cast(syntax: &SyntaxNode) -> Option<&Self> {
+        match syntax.kind() {
+            LITERAL_PAT => Some(LiteralPat::from_repr(syntax.into_repr())),
+            _ => None,
+        }
+    }
+    fn syntax(&self) -> &SyntaxNode { &self.syntax }
+}
+
+impl ToOwned for LiteralPat {
+    type Owned = TreeArc<LiteralPat>;
+    fn to_owned(&self) -> TreeArc<LiteralPat> { TreeArc::cast(self.syntax.to_owned()) }
+}
+
+
+impl LiteralPat {
+    pub fn literal(&self) -> Option<&Literal> {
+        super::child_opt(self)
+    }
+}
+
 // LoopExpr
 #[derive(Debug, PartialEq, Eq, Hash)]
 #[repr(transparent)]
@@ -2594,6 +2626,7 @@ pub enum PatKind<'a> {
     TuplePat(&'a TuplePat),
     SlicePat(&'a SlicePat),
     RangePat(&'a RangePat),
+    LiteralPat(&'a LiteralPat),
 }
 
 impl AstNode for Pat {
@@ -2607,7 +2640,8 @@ impl AstNode for Pat {
             | TUPLE_STRUCT_PAT
             | TUPLE_PAT
             | SLICE_PAT
-            | RANGE_PAT => Some(Pat::from_repr(syntax.into_repr())),
+            | RANGE_PAT
+            | LITERAL_PAT => Some(Pat::from_repr(syntax.into_repr())),
             _ => None,
         }
     }
@@ -2631,6 +2665,7 @@ impl Pat {
             TUPLE_PAT => PatKind::TuplePat(TuplePat::cast(&self.syntax).unwrap()),
             SLICE_PAT => PatKind::SlicePat(SlicePat::cast(&self.syntax).unwrap()),
             RANGE_PAT => PatKind::RangePat(RangePat::cast(&self.syntax).unwrap()),
+            LITERAL_PAT => PatKind::LiteralPat(LiteralPat::cast(&self.syntax).unwrap()),
             _ => unreachable!(),
         }
     }

crates/ra_syntax/src/grammar.ron

@@ -161,6 +161,7 @@ Grammar(
         "TUPLE_PAT",
         "SLICE_PAT",
         "RANGE_PAT",
+        "LITERAL_PAT",
 
         // atoms
         "TUPLE_EXPR",
@@ -524,6 +525,7 @@ Grammar(
         "TuplePat": ( collections: [["args", "Pat"]] ),
         "SlicePat": (),
         "RangePat": (),
+        "LiteralPat": (options: ["Literal"]),
 
         "Pat": (
             enum: [
@@ -536,6 +538,7 @@ Grammar(
                 "TuplePat",
                 "SlicePat",
                 "RangePat",
+                "LiteralPat",
             ],
         ),
 

crates/ra_syntax/src/grammar/patterns.rs

@@ -43,21 +43,8 @@ fn atom_pat(p: &mut Parser, recovery_set: TokenSet) -> Option<CompletedMarker> {
         return Some(path_pat(p));
     }
 
-    // test literal_pattern
-    // fn main() {
-    //     match () {
-    //         -1 => (),
-    //         92 => (),
-    //         'c' => (),
-    //         "hello" => (),
-    //     }
-    // }
-    if p.at(MINUS) && (p.nth(1) == INT_NUMBER || p.nth(1) == FLOAT_NUMBER) {
-        p.bump();
-    }
-
-    if let Some(m) = expressions::literal(p) {
-        return Some(m);
+    if is_literal_pat_start(p) {
+        return Some(literal_pat(p));
     }
 
     let m = match la0 {
@@ -73,6 +60,30 @@ fn atom_pat(p: &mut Parser, recovery_set: TokenSet) -> Option<CompletedMarker> {
     Some(m)
 }
 
+fn is_literal_pat_start(p: &mut Parser) -> bool {
+    p.at(MINUS) && (p.nth(1) == INT_NUMBER || p.nth(1) == FLOAT_NUMBER)
+        || p.at_ts(expressions::LITERAL_FIRST)
+}
+
+// test literal_pattern
+// fn main() {
+//     match () {
+//         -1 => (),
+//         92 => (),
+//         'c' => (),
+//         "hello" => (),
+//     }
+// }
+fn literal_pat(p: &mut Parser) -> CompletedMarker {
+    assert!(is_literal_pat_start(p));
+    let m = p.start();
+    if p.at(MINUS) {
+        p.bump();
+    }
+    expressions::literal(p);
+    m.complete(p, LITERAL_PAT)
+}
+
 // test path_part
 // fn foo() {
 //     let foo::Bar = ();

crates/ra_syntax/src/syntax_kinds/generated.rs

@@ -157,6 +157,7 @@ pub enum SyntaxKind {
     TUPLE_PAT,
     SLICE_PAT,
     RANGE_PAT,
+    LITERAL_PAT,
     TUPLE_EXPR,
     ARRAY_EXPR,
     PAREN_EXPR,
@@ -493,6 +494,7 @@ impl SyntaxKind {
             TUPLE_PAT => &SyntaxInfo { name: "TUPLE_PAT" },
             SLICE_PAT => &SyntaxInfo { name: "SLICE_PAT" },
             RANGE_PAT => &SyntaxInfo { name: "RANGE_PAT" },
+            LITERAL_PAT => &SyntaxInfo { name: "LITERAL_PAT" },
             TUPLE_EXPR => &SyntaxInfo { name: "TUPLE_EXPR" },
             ARRAY_EXPR => &SyntaxInfo { name: "ARRAY_EXPR" },
             PAREN_EXPR => &SyntaxInfo { name: "PAREN_EXPR" },