From def0a95d357f334b7329c3ee9e7da3c30563321c Mon Sep 17 00:00:00 2001
From: DJMcNab <36049421+DJMcNab@users.noreply.github.com>
Date: Wed, 19 Dec 2018 20:02:37 +0000
Subject: Revert "Revert to f6f7c5"

This approach is correct, but it needs an addition to Restrictions too

This reverts commit ad00d0c8a5f64142e6636e8b048204c8f8982f4a.
---
 crates/ra_syntax/src/grammar/expressions.rs | 39 +++++++++++++++++++----------
 1 file changed, 26 insertions(+), 13 deletions(-)

(limited to 'crates/ra_syntax/src/grammar/expressions.rs')

diff --git a/crates/ra_syntax/src/grammar/expressions.rs b/crates/ra_syntax/src/grammar/expressions.rs
index 512823ddf..9d75bfb90 100644
--- a/crates/ra_syntax/src/grammar/expressions.rs
+++ b/crates/ra_syntax/src/grammar/expressions.rs
@@ -158,18 +158,19 @@ 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 lhs = match lhs(p, r) {
-        Some(lhs) => {
+        (Some(lhs), macro_blocklike) => {
             // test stmt_bin_expr_ambiguity
             // fn foo() {
             //     let _ = {1} & 2;
             //     {1} &2;
             // }
-            if r.prefer_stmt && is_block(lhs.kind()) {
+            if r.prefer_stmt && (is_block(lhs.kind()) || macro_blocklike == Some(BlockLike::Block))
+            {
                 return BlockLike::Block;
             }
             lhs
         }
-        None => return BlockLike::NotBlock,
+        (None, _) => return BlockLike::NotBlock,
     };
 
     loop {
@@ -213,7 +214,7 @@ const LHS_FIRST: TokenSet = token_set_union![
     atom::ATOM_EXPR_FIRST,
 ];
 
-fn lhs(p: &mut Parser, r: Restrictions) -> Option<CompletedMarker> {
+fn lhs(p: &mut Parser, r: Restrictions) -> (Option<CompletedMarker>, Option<BlockLike>) {
     let m;
     let kind = match p.current() {
         // test ref_expr
@@ -246,18 +247,29 @@ fn lhs(p: &mut Parser, r: Restrictions) -> Option<CompletedMarker> {
             if p.at_ts(EXPR_FIRST) {
                 expr_bp(p, r, 2);
             }
-            return Some(m.complete(p, RANGE_EXPR));
+            return (Some(m.complete(p, RANGE_EXPR)), None);
         }
         _ => {
-            let lhs = atom::atom_expr(p, r)?;
-            return Some(postfix_expr(p, r, lhs));
+            let (lhs_marker, macro_block_like) = atom::atom_expr(p, r);
+
+            if macro_block_like == Some(BlockLike::Block) {
+                return (lhs_marker, macro_block_like);
+            }
+            if let Some(lhs_marker) = lhs_marker {
+                return (Some(postfix_expr(p, r, lhs_marker)), macro_block_like);
+            } else {
+                return (None, None);
+            }
         }
     };
     expr_bp(p, r, 255);
-    Some(m.complete(p, kind))
+    (Some(m.complete(p, kind)), None)
 }
 
 fn postfix_expr(p: &mut Parser, r: Restrictions, mut lhs: CompletedMarker) -> CompletedMarker {
+    // Calls are disallowed if the type is a block and we prefer statements because the call cannot be disambiguated from a tuple
+    // E.g. `while true {break}();` is parsed as
+    // `while true {break}; ();`
     let mut allow_calls = !r.prefer_stmt || !is_block(lhs.kind());
     loop {
         lhs = match p.current() {
@@ -406,21 +418,22 @@ fn arg_list(p: &mut Parser) {
 //     let _ = ::a::<b>;
 //     let _ = format!();
 // }
-fn path_expr(p: &mut Parser, r: Restrictions) -> CompletedMarker {
+fn path_expr(p: &mut Parser, r: Restrictions) -> (CompletedMarker, Option<BlockLike>) {
     assert!(paths::is_path_start(p) || p.at(L_ANGLE));
     let m = p.start();
     paths::expr_path(p);
-    match p.current() {
+    let res = match p.current() {
         L_CURLY if !r.forbid_structs => {
             named_field_list(p);
             m.complete(p, STRUCT_LIT)
         }
         EXCL => {
-            items::macro_call_after_excl(p); // TODO: Use return type (BlockLike)
-            m.complete(p, MACRO_CALL)
+            let block_like = items::macro_call_after_excl(p); // TODO: Use return type (BlockLike)
+            return (m.complete(p, MACRO_CALL), Some(block_like));
         }
         _ => m.complete(p, PATH_EXPR),
-    }
+    };
+    (res, None)
 }
 
 // test struct_lit
-- 
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