11 files changed, 224 insertions, 15 deletions

diff --git a/src/grammar.ron b/src/grammar.ron
index 960838c97..f1c3502bc 100644
--- a/src/grammar.ron
+++ b/src/grammar.ron
@@ -142,6 +142,7 @@ Grammar(
         "STRUCT_PAT",
         "TUPLE_STRUCT_PAT",
         "TUPLE_PAT",
+        "SLICE_PAT",
 
         // atoms
         "TUPLE_EXPR",
diff --git a/src/grammar/expressions/atom.rs b/src/grammar/expressions/atom.rs
index 524a69a8c..af9f47c5e 100644
--- a/src/grammar/expressions/atom.rs
+++ b/src/grammar/expressions/atom.rs
@@ -262,7 +262,7 @@ fn match_arm(p: &mut Parser) -> BlockLike {
         expr_no_struct(p);
     }
     p.expect(FAT_ARROW);
-    let ret = expr(p);
+    let ret = expr_stmt(p);
     m.complete(p, MATCH_ARM);
     ret
 }
@@ -295,7 +295,7 @@ pub(super) fn block_expr(p: &mut Parser) -> CompletedMarker {
                     // test pub_expr
                     // fn foo() { pub 92; } //FIXME
                     items::MaybeItem::None => {
-                        let is_blocklike = expressions::expr(p) == BlockLike::Block;
+                        let is_blocklike = expressions::expr_stmt(p) == BlockLike::Block;
                         if p.eat(SEMI) || (is_blocklike && !p.at(R_CURLY)) {
                             m.complete(p, EXPR_STMT);
                         } else {
diff --git a/src/grammar/expressions/mod.rs b/src/grammar/expressions/mod.rs
index ce709dbb2..dcbb1e2a8 100644
--- a/src/grammar/expressions/mod.rs
+++ b/src/grammar/expressions/mod.rs
@@ -6,12 +6,17 @@ pub(super) use self::atom::literal;
 const EXPR_FIRST: TokenSet = LHS_FIRST;
 
 pub(super) fn expr(p: &mut Parser) -> BlockLike {
-    let r = Restrictions { forbid_structs: false };
+    let r = Restrictions { forbid_structs: false, prefer_stmt: false };
+    expr_bp(p, r, 1)
+}
+
+pub(super) fn expr_stmt(p: &mut Parser) -> BlockLike {
+    let r = Restrictions { forbid_structs: false, prefer_stmt: true };
     expr_bp(p, r, 1)
 }
 
 fn expr_no_struct(p: &mut Parser) {
-    let r = Restrictions { forbid_structs: true };
+    let r = Restrictions { forbid_structs: true, prefer_stmt: false };
     expr_bp(p, r, 1);
 }
 
@@ -30,7 +35,8 @@ pub(super) fn block(p: &mut Parser) {
 
 #[derive(Clone, Copy)]
 struct Restrictions {
-    forbid_structs: bool
+    forbid_structs: bool,
+    prefer_stmt: bool,
 }
 
 enum Op {
@@ -86,12 +92,18 @@ fn current_op(p: &Parser) -> (u8, Op) {
 
 // Parses expression with binding power of at least bp.
 fn expr_bp(p: &mut Parser, r: Restrictions, bp: u8) -> BlockLike {
-    let mut block: bool;
     let mut lhs = match lhs(p, r) {
         Some(lhs) => {
-            block = is_block(lhs.kind());
+            // test stmt_bin_expr_ambiguity
+            // fn foo() {
+            //     let _ = {1} & 2;
+            //     {1} &2;
+            // }
+            if r.prefer_stmt && is_block(lhs.kind()) {
+                return BlockLike::Block;
+            }
             lhs
-        },
+        }
         None => return BlockLike::NotBlock,
     };
 
@@ -101,7 +113,6 @@ fn expr_bp(p: &mut Parser, r: Restrictions, bp: u8) -> BlockLike {
         if op_bp < bp {
             break;
         }
-        block = false;
         let m = lhs.precede(p);
         match op {
             Op::Simple => p.bump(),
@@ -112,7 +123,7 @@ fn expr_bp(p: &mut Parser, r: Restrictions, bp: u8) -> BlockLike {
         expr_bp(p, r, op_bp + 1);
         lhs = m.complete(p, if is_range { RANGE_EXPR } else { BIN_EXPR });
     }
-    if block { BlockLike::Block } else { BlockLike::NotBlock }
+    BlockLike::NotBlock
 }
 
 // test no_semi_after_block
@@ -171,18 +182,27 @@ fn lhs(p: &mut Parser, r: Restrictions) -> Option<CompletedMarker> {
         }
         _ => {
             let lhs = atom::atom_expr(p, r)?;
-            return Some(postfix_expr(p, lhs));
+            return Some(postfix_expr(p, r, lhs));
         }
     };
     expr_bp(p, r, 255);
     Some(m.complete(p, kind))
 }
 
-fn postfix_expr(p: &mut Parser, mut lhs: CompletedMarker) -> CompletedMarker {
+fn postfix_expr(p: &mut Parser, r: Restrictions, mut lhs: CompletedMarker) -> CompletedMarker {
+    let mut allow_calls = !r.prefer_stmt || !is_block(lhs.kind());
     loop {
         lhs = match p.current() {
-            L_PAREN => call_expr(p, lhs),
-            L_BRACK => index_expr(p, lhs),
+            // test stmt_postfix_expr_ambiguity
+            // fn foo() {
+            //     match () {
+            //         _ => {}
+            //         () => {}
+            //         [] => {}
+            //     }
+            // }
+            L_PAREN if allow_calls => call_expr(p, lhs),
+            L_BRACK if allow_calls => index_expr(p, lhs),
             DOT if p.nth(1) == IDENT => if p.nth(2) == L_PAREN || p.nth(2) == COLONCOLON {
                 method_call_expr(p, lhs)
             } else {
@@ -199,7 +219,8 @@ fn postfix_expr(p: &mut Parser, mut lhs: CompletedMarker) -> CompletedMarker {
             QUESTION => try_expr(p, lhs),
             AS_KW => cast_expr(p, lhs),
             _ => break,
-        }
+        };
+        allow_calls = true
     }
     lhs
 }
diff --git a/src/grammar/patterns.rs b/src/grammar/patterns.rs
index f1d48b5fa..36ead7561 100644
--- a/src/grammar/patterns.rs
+++ b/src/grammar/patterns.rs
@@ -17,6 +17,7 @@ pub(super) fn pattern(p: &mut Parser) {
         UNDERSCORE => placeholder_pat(p),
         AMP => ref_pat(p),
         L_PAREN => tuple_pat(p),
+        L_BRACK => slice_pat(p),
         _ => p.err_and_bump("expected pattern"),
     }
 }
@@ -128,6 +129,28 @@ fn tuple_pat(p: &mut Parser) {
     m.complete(p, TUPLE_PAT);
 }
 
+// test slice_pat
+// fn main() {
+//     let [a, b, ..] = [];
+// }
+fn slice_pat(p: &mut Parser) {
+    assert!(p.at(L_BRACK));
+    let m = p.start();
+    p.bump();
+    while !p.at(EOF) && !p.at(R_BRACK) {
+        match p.current() {
+            DOTDOT => p.bump(),
+            _ => pattern(p),
+        }
+        if !p.at(R_BRACK) {
+            p.expect(COMMA);
+        }
+    }
+    p.expect(R_BRACK);
+
+    m.complete(p, SLICE_PAT);
+}
+
 // test bind_pat
 // fn main() {
 //     let a = ();
diff --git a/src/syntax_kinds/generated.rs b/src/syntax_kinds/generated.rs
index cf286a0f1..0c6a1f8e7 100644
--- a/src/syntax_kinds/generated.rs
+++ b/src/syntax_kinds/generated.rs
@@ -134,6 +134,7 @@ pub enum SyntaxKind {
     STRUCT_PAT,
     TUPLE_STRUCT_PAT,
     TUPLE_PAT,
+    SLICE_PAT,
     TUPLE_EXPR,
     ARRAY_EXPR,
     PAREN_EXPR,
@@ -372,6 +373,7 @@ impl SyntaxKind {
             STRUCT_PAT => &SyntaxInfo { name: "STRUCT_PAT" },
             TUPLE_STRUCT_PAT => &SyntaxInfo { name: "TUPLE_STRUCT_PAT" },
             TUPLE_PAT => &SyntaxInfo { name: "TUPLE_PAT" },
+            SLICE_PAT => &SyntaxInfo { name: "SLICE_PAT" },
             TUPLE_EXPR => &SyntaxInfo { name: "TUPLE_EXPR" },
             ARRAY_EXPR => &SyntaxInfo { name: "ARRAY_EXPR" },
             PAREN_EXPR => &SyntaxInfo { name: "PAREN_EXPR" },
diff --git a/tests/data/parser/inline/0087_stmt_postfix_expr_ambiguity.rs b/tests/data/parser/inline/0087_stmt_postfix_expr_ambiguity.rs
new file mode 100644
index 000000000..2edd578f9
--- /dev/null
+++ b/tests/data/parser/inline/0087_stmt_postfix_expr_ambiguity.rs
@@ -0,0 +1,7 @@
+fn foo() {
+    match () {
+        _ => {}
+        () => {}
+        [] => {}
+    }
+}
diff --git a/tests/data/parser/inline/0087_stmt_postfix_expr_ambiguity.txt b/tests/data/parser/inline/0087_stmt_postfix_expr_ambiguity.txt
new file mode 100644
index 000000000..47b4d4481
--- /dev/null
+++ b/tests/data/parser/inline/0087_stmt_postfix_expr_ambiguity.txt
@@ -0,0 +1,58 @@
+FILE@[0; 84)
+  FN_ITEM@[0; 83)
+    FN_KW@[0; 2)
+    WHITESPACE@[2; 3)
+    NAME@[3; 6)
+      IDENT@[3; 6) "foo"
+    PARAM_LIST@[6; 8)
+      L_PAREN@[6; 7)
+      R_PAREN@[7; 8)
+    WHITESPACE@[8; 9)
+    BLOCK_EXPR@[9; 83)
+      L_CURLY@[9; 10)
+      WHITESPACE@[10; 15)
+      MATCH_EXPR@[15; 81)
+        MATCH_KW@[15; 20)
+        WHITESPACE@[20; 21)
+        TUPLE_EXPR@[21; 23)
+          L_PAREN@[21; 22)
+          R_PAREN@[22; 23)
+        WHITESPACE@[23; 24)
+        L_CURLY@[24; 25)
+        WHITESPACE@[25; 34)
+        MATCH_ARM@[34; 41)
+          PLACEHOLDER_PAT@[34; 35)
+            UNDERSCORE@[34; 35)
+          WHITESPACE@[35; 36)
+          FAT_ARROW@[36; 38)
+          WHITESPACE@[38; 39)
+          BLOCK_EXPR@[39; 41)
+            L_CURLY@[39; 40)
+            R_CURLY@[40; 41)
+        WHITESPACE@[41; 50)
+        MATCH_ARM@[50; 58)
+          TUPLE_PAT@[50; 52)
+            L_PAREN@[50; 51)
+            R_PAREN@[51; 52)
+          WHITESPACE@[52; 53)
+          FAT_ARROW@[53; 55)
+          WHITESPACE@[55; 56)
+          BLOCK_EXPR@[56; 58)
+            L_CURLY@[56; 57)
+            R_CURLY@[57; 58)
+        WHITESPACE@[58; 67)
+        MATCH_ARM@[67; 75)
+          SLICE_PAT@[67; 69)
+            L_BRACK@[67; 68)
+            R_BRACK@[68; 69)
+          WHITESPACE@[69; 70)
+          FAT_ARROW@[70; 72)
+          WHITESPACE@[72; 73)
+          BLOCK_EXPR@[73; 75)
+            L_CURLY@[73; 74)
+            R_CURLY@[74; 75)
+        WHITESPACE@[75; 80)
+        R_CURLY@[80; 81)
+      WHITESPACE@[81; 82)
+      R_CURLY@[82; 83)
+  WHITESPACE@[83; 84)
diff --git a/tests/data/parser/inline/0088_stmt_bin_expr_ambiguity.rs b/tests/data/parser/inline/0088_stmt_bin_expr_ambiguity.rs
new file mode 100644
index 000000000..37b843742
--- /dev/null
+++ b/tests/data/parser/inline/0088_stmt_bin_expr_ambiguity.rs
@@ -0,0 +1,4 @@
+fn foo() {
+    let _ = {1} & 2;
+    {1} &2;
+}
diff --git a/tests/data/parser/inline/0088_stmt_bin_expr_ambiguity.txt b/tests/data/parser/inline/0088_stmt_bin_expr_ambiguity.txt
new file mode 100644
index 000000000..df0aa44b3
--- /dev/null
+++ b/tests/data/parser/inline/0088_stmt_bin_expr_ambiguity.txt
@@ -0,0 +1,50 @@
+FILE@[0; 46)
+  FN_ITEM@[0; 45)
+    FN_KW@[0; 2)
+    WHITESPACE@[2; 3)
+    NAME@[3; 6)
+      IDENT@[3; 6) "foo"
+    PARAM_LIST@[6; 8)
+      L_PAREN@[6; 7)
+      R_PAREN@[7; 8)
+    WHITESPACE@[8; 9)
+    BLOCK_EXPR@[9; 45)
+      L_CURLY@[9; 10)
+      WHITESPACE@[10; 15)
+      LET_STMT@[15; 31)
+        LET_KW@[15; 18)
+        WHITESPACE@[18; 19)
+        PLACEHOLDER_PAT@[19; 20)
+          UNDERSCORE@[19; 20)
+        WHITESPACE@[20; 21)
+        EQ@[21; 22)
+        WHITESPACE@[22; 23)
+        BIN_EXPR@[23; 30)
+          BLOCK_EXPR@[23; 26)
+            L_CURLY@[23; 24)
+            LITERAL@[24; 25)
+              INT_NUMBER@[24; 25) "1"
+            R_CURLY@[25; 26)
+          WHITESPACE@[26; 27)
+          AMP@[27; 28)
+          WHITESPACE@[28; 29)
+          LITERAL@[29; 30)
+            INT_NUMBER@[29; 30) "2"
+        SEMI@[30; 31)
+      WHITESPACE@[31; 36)
+      EXPR_STMT@[36; 39)
+        BLOCK_EXPR@[36; 39)
+          L_CURLY@[36; 37)
+          LITERAL@[37; 38)
+            INT_NUMBER@[37; 38) "1"
+          R_CURLY@[38; 39)
+      WHITESPACE@[39; 40)
+      EXPR_STMT@[40; 43)
+        REF_EXPR@[40; 42)
+          AMP@[40; 41)
+          LITERAL@[41; 42)
+            INT_NUMBER@[41; 42) "2"
+        SEMI@[42; 43)
+      WHITESPACE@[43; 44)
+      R_CURLY@[44; 45)
+  WHITESPACE@[45; 46)
diff --git a/tests/data/parser/inline/0089_slice_pat.rs b/tests/data/parser/inline/0089_slice_pat.rs
new file mode 100644
index 000000000..7955973b9
--- /dev/null
+++ b/tests/data/parser/inline/0089_slice_pat.rs
@@ -0,0 +1,3 @@
+fn main() {
+    let [a, b, ..] = [];
+}
diff --git a/tests/data/parser/inline/0089_slice_pat.txt b/tests/data/parser/inline/0089_slice_pat.txt
new file mode 100644
index 000000000..1e7f20119
--- /dev/null
+++ b/tests/data/parser/inline/0089_slice_pat.txt
@@ -0,0 +1,40 @@
+FILE@[0; 39)
+  FN_ITEM@[0; 38)
+    FN_KW@[0; 2)
+    WHITESPACE@[2; 3)
+    NAME@[3; 7)
+      IDENT@[3; 7) "main"
+    PARAM_LIST@[7; 9)
+      L_PAREN@[7; 8)
+      R_PAREN@[8; 9)
+    WHITESPACE@[9; 10)
+    BLOCK_EXPR@[10; 38)
+      L_CURLY@[10; 11)
+      WHITESPACE@[11; 16)
+      LET_STMT@[16; 36)
+        LET_KW@[16; 19)
+        WHITESPACE@[19; 20)
+        SLICE_PAT@[20; 30)
+          L_BRACK@[20; 21)
+          BIND_PAT@[21; 22)
+            NAME@[21; 22)
+              IDENT@[21; 22) "a"
+          COMMA@[22; 23)
+          WHITESPACE@[23; 24)
+          BIND_PAT@[24; 25)
+            NAME@[24; 25)
+              IDENT@[24; 25) "b"
+          COMMA@[25; 26)
+          WHITESPACE@[26; 27)
+          DOTDOT@[27; 29)
+          R_BRACK@[29; 30)
+        WHITESPACE@[30; 31)
+        EQ@[31; 32)
+        WHITESPACE@[32; 33)
+        ARRAY_EXPR@[33; 35)
+          L_BRACK@[33; 34)
+          R_BRACK@[34; 35)
+        SEMI@[35; 36)
+      WHITESPACE@[36; 37)
+      R_CURLY@[37; 38)
+  WHITESPACE@[38; 39)