8 files changed, 120 insertions, 7 deletions

diff --git a/src/grammar.ron b/src/grammar.ron
index a9a3847c9..9912f9698 100644
--- a/src/grammar.ron
+++ b/src/grammar.ron
@@ -60,6 +60,7 @@ Grammar(
         "loop",
         "while",
         "if",
+        "else",
         "match",
         "const",
         "static",
@@ -134,6 +135,7 @@ Grammar(
         "LAMBDA_EXPR",
         "STRUCT_LIT",
         "STRUCT_LIT_FIELD",
+        "IF_EXPR",
 
         "EXTERN_BLOCK",
         "ENUM_VARIANT",
diff --git a/src/grammar/expressions.rs b/src/grammar/expressions.rs
index e2be13a77..ed9236b02 100644
--- a/src/grammar/expressions.rs
+++ b/src/grammar/expressions.rs
@@ -145,14 +145,16 @@ fn atom_expr(p: &mut Parser) -> Option<CompletedMarker> {
         return Some(path_expr(p));
     }
 
-    match p.current() {
-        L_PAREN => Some(tuple_expr(p)),
-        PIPE => Some(lambda_expr(p)),
+    let done = match p.current() {
+        L_PAREN => tuple_expr(p),
+        PIPE => lambda_expr(p),
+        IF_KW => if_expr(p),
         _ => {
             p.err_and_bump("expected expression");
-            None
+            return None;
         }
-    }
+    };
+    Some(done)
 }
 
 fn tuple_expr(p: &mut Parser) -> CompletedMarker {
@@ -182,6 +184,29 @@ fn lambda_expr(p: &mut Parser) -> CompletedMarker {
     m.complete(p, LAMBDA_EXPR)
 }
 
+// test if_expr
+// fn foo() {
+//     if true {};
+//     if true {} else {};
+//     if true {} else if false {} else {}
+// }
+fn if_expr(p: &mut Parser) -> CompletedMarker {
+    assert!(p.at(IF_KW));
+    let m = p.start();
+    p.bump();
+    expr(p);
+    block(p);
+    if p.at(ELSE_KW) {
+        p.bump();
+        if p.at(IF_KW) {
+            if_expr(p);
+        } else {
+            block(p);
+        }
+    }
+    m.complete(p, IF_EXPR)
+}
+
 // test call_expr
 // fn foo() {
 //     let _ = f();
diff --git a/src/syntax_kinds/generated.rs b/src/syntax_kinds/generated.rs
index 2f7c29008..35d9640fa 100644
--- a/src/syntax_kinds/generated.rs
+++ b/src/syntax_kinds/generated.rs
@@ -61,6 +61,7 @@ pub enum SyntaxKind {
     LOOP_KW,
     WHILE_KW,
     IF_KW,
+    ELSE_KW,
     MATCH_KW,
     CONST_KW,
     STATIC_KW,
@@ -125,6 +126,7 @@ pub enum SyntaxKind {
     LAMBDA_EXPR,
     STRUCT_LIT,
     STRUCT_LIT_FIELD,
+    IF_EXPR,
     EXTERN_BLOCK,
     ENUM_VARIANT,
     NAMED_FIELD,
@@ -223,6 +225,7 @@ impl SyntaxKind {
             LOOP_KW => &SyntaxInfo { name: "LOOP_KW" },
             WHILE_KW => &SyntaxInfo { name: "WHILE_KW" },
             IF_KW => &SyntaxInfo { name: "IF_KW" },
+            ELSE_KW => &SyntaxInfo { name: "ELSE_KW" },
             MATCH_KW => &SyntaxInfo { name: "MATCH_KW" },
             CONST_KW => &SyntaxInfo { name: "CONST_KW" },
             STATIC_KW => &SyntaxInfo { name: "STATIC_KW" },
@@ -287,6 +290,7 @@ impl SyntaxKind {
             LAMBDA_EXPR => &SyntaxInfo { name: "LAMBDA_EXPR" },
             STRUCT_LIT => &SyntaxInfo { name: "STRUCT_LIT" },
             STRUCT_LIT_FIELD => &SyntaxInfo { name: "STRUCT_LIT_FIELD" },
+            IF_EXPR => &SyntaxInfo { name: "IF_EXPR" },
             EXTERN_BLOCK => &SyntaxInfo { name: "EXTERN_BLOCK" },
             ENUM_VARIANT => &SyntaxInfo { name: "ENUM_VARIANT" },
             NAMED_FIELD => &SyntaxInfo { name: "NAMED_FIELD" },
@@ -344,6 +348,7 @@ impl SyntaxKind {
             "loop" => LOOP_KW,
             "while" => WHILE_KW,
             "if" => IF_KW,
+            "else" => ELSE_KW,
             "match" => MATCH_KW,
             "const" => CONST_KW,
             "static" => STATIC_KW,
@@ -445,6 +450,7 @@ impl SyntaxKind {
             LOOP_KW => "loop",
             WHILE_KW => "while",
             IF_KW => "if",
+            ELSE_KW => "else",
             MATCH_KW => "match",
             CONST_KW => "const",
             STATIC_KW => "static",
diff --git a/tests/data/lexer/0011_keywords.rs b/tests/data/lexer/0011_keywords.rs
index 97ff3f954..2a78b5dd2 100644
--- a/tests/data/lexer/0011_keywords.rs
+++ b/tests/data/lexer/0011_keywords.rs
@@ -1,3 +1,3 @@
 fn use struct trait enum impl true false as extern crate
 mod pub self super in where for loop while if match const
-static mut type ref let
+static mut type ref let else
diff --git a/tests/data/lexer/0011_keywords.txt b/tests/data/lexer/0011_keywords.txt
index 851a671f5..e25d7d4b4 100644
--- a/tests/data/lexer/0011_keywords.txt
+++ b/tests/data/lexer/0011_keywords.txt
@@ -53,4 +53,6 @@ WHITESPACE 1 " "
 REF_KW 3 "ref"
 WHITESPACE 1 " "
 LET_KW 3 "let"
+WHITESPACE 1 " "
+ELSE_KW 4 "else"
 WHITESPACE 1 "\n"
diff --git a/tests/data/parser/err/0008_item_block_recovery.txt b/tests/data/parser/err/0008_item_block_recovery.txt
index 40ce2bc1a..81a5dd4c3 100644
--- a/tests/data/parser/err/0008_item_block_recovery.txt
+++ b/tests/data/parser/err/0008_item_block_recovery.txt
@@ -37,7 +37,7 @@ FILE@[0; 95)
     WHITESPACE@[45; 50)
     R_CURLY@[50; 51)
     WHITESPACE@[51; 52)
-    IDENT@[52; 56) "else"
+    ELSE_KW@[52; 56)
     WHITESPACE@[56; 57)
     L_CURLY@[57; 58)
     WHITESPACE@[58; 67)
diff --git a/tests/data/parser/inline/0065_if_expr.rs b/tests/data/parser/inline/0065_if_expr.rs
new file mode 100644
index 000000000..f1691c159
--- /dev/null
+++ b/tests/data/parser/inline/0065_if_expr.rs
@@ -0,0 +1,5 @@
+fn foo() {
+    if true {};
+    if true {} else {};
+    if true {} else if false {} else {}
+}
diff --git a/tests/data/parser/inline/0065_if_expr.txt b/tests/data/parser/inline/0065_if_expr.txt
new file mode 100644
index 000000000..5d9bdfb13
--- /dev/null
+++ b/tests/data/parser/inline/0065_if_expr.txt
@@ -0,0 +1,73 @@
+FILE@[0; 93)
+  FN_ITEM@[0; 93)
+    FN_KW@[0; 2)
+    NAME@[2; 6)
+      WHITESPACE@[2; 3)
+      IDENT@[3; 6) "foo"
+    PARAM_LIST@[6; 9)
+      L_PAREN@[6; 7)
+      R_PAREN@[7; 8)
+      WHITESPACE@[8; 9)
+    BLOCK@[9; 93)
+      L_CURLY@[9; 10)
+      EXPR_STMT@[10; 31)
+        IF_EXPR@[10; 25)
+          WHITESPACE@[10; 15)
+          IF_KW@[15; 17)
+          LITERAL@[17; 23)
+            WHITESPACE@[17; 18)
+            TRUE_KW@[18; 22)
+            WHITESPACE@[22; 23)
+          BLOCK@[23; 25)
+            L_CURLY@[23; 24)
+            R_CURLY@[24; 25)
+        SEMI@[25; 26)
+        WHITESPACE@[26; 31)
+      EXPR_STMT@[31; 55)
+        IF_EXPR@[31; 49)
+          IF_KW@[31; 33)
+          LITERAL@[33; 39)
+            WHITESPACE@[33; 34)
+            TRUE_KW@[34; 38)
+            WHITESPACE@[38; 39)
+          BLOCK@[39; 42)
+            L_CURLY@[39; 40)
+            R_CURLY@[40; 41)
+            WHITESPACE@[41; 42)
+          ELSE_KW@[42; 46)
+          BLOCK@[46; 49)
+            WHITESPACE@[46; 47)
+            L_CURLY@[47; 48)
+            R_CURLY@[48; 49)
+        SEMI@[49; 50)
+        WHITESPACE@[50; 55)
+      IF_EXPR@[55; 91)
+        IF_KW@[55; 57)
+        LITERAL@[57; 63)
+          WHITESPACE@[57; 58)
+          TRUE_KW@[58; 62)
+          WHITESPACE@[62; 63)
+        BLOCK@[63; 66)
+          L_CURLY@[63; 64)
+          R_CURLY@[64; 65)
+          WHITESPACE@[65; 66)
+        ELSE_KW@[66; 70)
+        IF_EXPR@[70; 91)
+          WHITESPACE@[70; 71)
+          IF_KW@[71; 73)
+          LITERAL@[73; 80)
+            WHITESPACE@[73; 74)
+            FALSE_KW@[74; 79)
+            WHITESPACE@[79; 80)
+          BLOCK@[80; 83)
+            L_CURLY@[80; 81)
+            R_CURLY@[81; 82)
+            WHITESPACE@[82; 83)
+          ELSE_KW@[83; 87)
+          BLOCK@[87; 91)
+            WHITESPACE@[87; 88)
+            L_CURLY@[88; 89)
+            R_CURLY@[89; 90)
+            WHITESPACE@[90; 91)
+      R_CURLY@[91; 92)
+      WHITESPACE@[92; 93)