Merge #4221

4221: Special-case try macro to better support 2015 edition r=matklad a=matklad



bors r+
🤖

Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>

Author: bors[bot]

crates/ra_parser/src/grammar/expressions/atom.rs

@@ -535,6 +535,22 @@ fn break_expr(p: &mut Parser, r: Restrictions) -> CompletedMarker {
 fn try_block_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
     assert!(p.at(T![try]));
     let m = m.unwrap_or_else(|| p.start());
+    // Special-case `try!` as macro.
+    // This is a hack until we do proper edition support
+    if p.nth_at(1, T![!]) {
+        // test try_macro_fallback
+        // fn foo() { try!(Ok(())); }
+        let path = p.start();
+        let path_segment = p.start();
+        let name_ref = p.start();
+        p.bump_remap(IDENT);
+        name_ref.complete(p, NAME_REF);
+        path_segment.complete(p, PATH_SEGMENT);
+        path.complete(p, PATH);
+        let _block_like = items::macro_call_after_excl(p);
+        return m.complete(p, MACRO_CALL);
+    }
+
     p.bump(T![try]);
     block(p);
     m.complete(p, TRY_EXPR)

crates/ra_syntax/test_data/parser/inline/ok/0159_try_macro_fallback.rast

@@ -0,0 +1,35 @@
+SOURCE_FILE@0..27
+  FN_DEF@0..26
+    FN_KW@0..2 "fn"
+    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..26
+      BLOCK@9..26
+        L_CURLY@9..10 "{"
+        WHITESPACE@10..11 " "
+        EXPR_STMT@11..24
+          MACRO_CALL@11..23
+            PATH@11..14
+              PATH_SEGMENT@11..14
+                NAME_REF@11..14
+                  IDENT@11..14 "try"
+            BANG@14..15 "!"
+            TOKEN_TREE@15..23
+              L_PAREN@15..16 "("
+              IDENT@16..18 "Ok"
+              TOKEN_TREE@18..22
+                L_PAREN@18..19 "("
+                TOKEN_TREE@19..21
+                  L_PAREN@19..20 "("
+                  R_PAREN@20..21 ")"
+                R_PAREN@21..22 ")"
+              R_PAREN@22..23 ")"
+          SEMICOLON@23..24 ";"
+        WHITESPACE@24..25 " "
+        R_CURLY@25..26 "}"
+  WHITESPACE@26..27 "\n"

crates/ra_syntax/test_data/parser/inline/ok/0159_try_macro_fallback.rs

@@ -0,0 +1 @@
+fn foo() { try!(Ok(())); }