Fix macro expansion for statements w/o semicolon

Cargo.lock

@@ -1811,9 +1811,9 @@ checksum = "56dee185309b50d1f11bfedef0fe6d036842e3fb77413abef29f8f8d1c5d4c1c"
 
 [[package]]
 name = "ungrammar"
-version = "1.11.0"
+version = "1.12.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "84c629795d377049f2a1dc5f42cf505dc5ba8b28a5df0a03f4183a24480e4a6a"
+checksum = "df6586a7c530704efe803d49a0b4132dcbdb4063163df39110548e6b5f2373ba"
 
 [[package]]
 name = "unicase"

crates/hir_def/src/body/lower.rs

@@ -519,7 +519,7 @@ impl ExprCollector<'_> {
             }
             ast::Expr::MacroCall(e) => {
                 let mut ids = vec![];
-                self.collect_macro_call(e, syntax_ptr.clone(), |this, expansion| {
+                self.collect_macro_call(e, syntax_ptr.clone(), true, |this, expansion| {
                     ids.push(match expansion {
                         Some(it) => this.collect_expr(it),
                         None => this.alloc_expr(Expr::Missing, syntax_ptr.clone()),
@@ -527,6 +527,17 @@ impl ExprCollector<'_> {
                 });
                 ids[0]
             }
+            ast::Expr::MacroStmts(e) => {
+                // FIXME:  these statements should be held by some hir containter
+                for stmt in e.statements() {
+                    self.collect_stmt(stmt);
+                }
+                if let Some(expr) = e.expr() {
+                    self.collect_expr(expr)
+                } else {
+                    self.alloc_expr(Expr::Missing, syntax_ptr)
+                }
+            }
         }
     }
 
@@ -534,6 +545,7 @@ impl ExprCollector<'_> {
         &mut self,
         e: ast::MacroCall,
         syntax_ptr: AstPtr<ast::Expr>,
+        is_error_recoverable: bool,
         mut collector: F,
     ) {
         // File containing the macro call. Expansion errors will be attached here.
@@ -567,7 +579,7 @@ impl ExprCollector<'_> {
             Some((mark, expansion)) => {
                 // FIXME: Statements are too complicated to recover from error for now.
                 // It is because we don't have any hygiene for local variable expansion right now.
-                if T::can_cast(syntax::SyntaxKind::MACRO_STMTS) && res.err.is_some() {
+                if !is_error_recoverable && res.err.is_some() {
                     self.expander.exit(self.db, mark);
                     collector(self, None);
                 } else {
@@ -591,8 +603,7 @@ impl ExprCollector<'_> {
     }
 
     fn collect_stmt(&mut self, s: ast::Stmt) -> Option<Vec<Statement>> {
-        let stmt =
+        let stmt = match s {
-            match s {
             ast::Stmt::LetStmt(stmt) => {
                 self.check_cfg(&stmt)?;
 
@@ -609,7 +620,7 @@ impl ExprCollector<'_> {
                     let syntax_ptr = AstPtr::new(&stmt.expr().unwrap());
                     let mut stmts = vec![];
 
-                        self.collect_macro_call(m, syntax_ptr.clone(), |this, expansion| {
+                    self.collect_macro_call(m, syntax_ptr.clone(), false, |this, expansion| {
                         match expansion {
                             Some(expansion) => {
                                 let statements: ast::MacroStmts = expansion;

crates/hir_def/src/item_tree.rs

@@ -110,6 +110,11 @@ impl ItemTree {
                     // still need to collect inner items.
                     ctx.lower_inner_items(e.syntax())
                 },
+                ast::ExprStmt(stmt) => {
+                    // Macros can expand to stmt. We return an empty item tree in this case, but
+                    // still need to collect inner items.
+                    ctx.lower_inner_items(stmt.syntax())
+                },
                 _ => {
                     panic!("cannot create item tree from {:?} {}", syntax, syntax);
                 },

crates/hir_expand/src/db.rs

@@ -401,13 +401,14 @@ fn to_fragment_kind(db: &dyn AstDatabase, id: MacroCallId) -> FragmentKind {
 
     match parent.kind() {
         MACRO_ITEMS | SOURCE_FILE => FragmentKind::Items,
+        MACRO_STMTS => FragmentKind::Statement,
         ITEM_LIST => FragmentKind::Items,
         LET_STMT => {
             // FIXME: Handle Pattern
             FragmentKind::Expr
         }
         EXPR_STMT => FragmentKind::Statements,
-        BLOCK_EXPR => FragmentKind::Expr,
+        BLOCK_EXPR => FragmentKind::Statements,
         ARG_LIST => FragmentKind::Expr,
         TRY_EXPR => FragmentKind::Expr,
         TUPLE_EXPR => FragmentKind::Expr,

crates/hir_ty/src/tests/macros.rs

@@ -215,6 +215,22 @@ fn expr_macro_expanded_in_various_places() {
     );
 }
 
+#[test]
+fn expr_macro_expanded_in_stmts() {
+    check_infer(
+        r#"
+        macro_rules! id { ($($es:tt)*) => { $($es)* } }
+        fn foo() {
+            id! { let a = (); }
+        }
+        "#,
+        expect![[r#"
+            !0..8 'leta=();': ()
+            57..84 '{     ...); } }': ()
+        "#]],
+    );
+}
+
 #[test]
 fn infer_type_value_macro_having_same_name() {
     check_infer(

crates/mbe/src/tests.rs

@@ -662,7 +662,6 @@ fn test_tt_to_stmts() {
         LITERAL@12..13
           INT_NUMBER@12..13 "1"
     SEMICOLON@13..14 ";"
-  EXPR_STMT@14..15
   PATH_EXPR@14..15
     PATH@14..15
       PATH_SEGMENT@14..15

crates/parser/src/grammar.rs

@@ -63,11 +63,11 @@ pub(crate) mod fragments {
     }
 
     pub(crate) fn stmt(p: &mut Parser) {
-        expressions::stmt(p, expressions::StmtWithSemi::No)
+        expressions::stmt(p, expressions::StmtWithSemi::No, true)
     }
 
     pub(crate) fn stmt_optional_semi(p: &mut Parser) {
-        expressions::stmt(p, expressions::StmtWithSemi::Optional)
+        expressions::stmt(p, expressions::StmtWithSemi::Optional, false)
     }
 
     pub(crate) fn opt_visibility(p: &mut Parser) {
@@ -133,7 +133,7 @@ pub(crate) mod fragments {
                 continue;
             }
 
-            expressions::stmt(p, expressions::StmtWithSemi::Optional);
+            expressions::stmt(p, expressions::StmtWithSemi::Optional, true);
         }
 
         m.complete(p, MACRO_STMTS);

crates/parser/src/grammar/expressions.rs

@@ -54,7 +54,7 @@ fn is_expr_stmt_attr_allowed(kind: SyntaxKind) -> bool {
     !forbid
 }
 
-pub(super) fn stmt(p: &mut Parser, with_semi: StmtWithSemi) {
+pub(super) fn stmt(p: &mut Parser, with_semi: StmtWithSemi, prefer_expr: bool) {
     let m = p.start();
     // test attr_on_expr_stmt
     // fn foo() {
@@ -90,7 +90,7 @@ pub(super) fn stmt(p: &mut Parser, with_semi: StmtWithSemi) {
         p.error(format!("attributes are not allowed on {:?}", kind));
     }
 
-    if p.at(T!['}']) {
+    if p.at(T!['}']) || (prefer_expr && p.at(EOF)) {
         // test attr_on_last_expr_in_block
         // fn foo() {
         //     { #[A] bar!()? }
@@ -198,7 +198,7 @@ pub(super) fn expr_block_contents(p: &mut Parser) {
             continue;
         }
 
-        stmt(p, StmtWithSemi::Yes)
+        stmt(p, StmtWithSemi::Yes, false)
     }
 }
 

crates/syntax/src/ast/generated/nodes.rs

@@ -1336,6 +1336,7 @@ pub enum Expr {
     Literal(Literal),
     LoopExpr(LoopExpr),
     MacroCall(MacroCall),
+    MacroStmts(MacroStmts),
     MatchExpr(MatchExpr),
     MethodCallExpr(MethodCallExpr),
     ParenExpr(ParenExpr),
@@ -3034,6 +3035,9 @@ impl From<LoopExpr> for Expr {
 impl From<MacroCall> for Expr {
     fn from(node: MacroCall) -> Expr { Expr::MacroCall(node) }
 }
+impl From<MacroStmts> for Expr {
+    fn from(node: MacroStmts) -> Expr { Expr::MacroStmts(node) }
+}
 impl From<MatchExpr> for Expr {
     fn from(node: MatchExpr) -> Expr { Expr::MatchExpr(node) }
 }
@@ -3078,8 +3082,8 @@ impl AstNode for Expr {
         match kind {
             ARRAY_EXPR | AWAIT_EXPR | BIN_EXPR | BLOCK_EXPR | BOX_EXPR | BREAK_EXPR | CALL_EXPR
             | CAST_EXPR | CLOSURE_EXPR | CONTINUE_EXPR | EFFECT_EXPR | FIELD_EXPR | FOR_EXPR
-            | IF_EXPR | INDEX_EXPR | LITERAL | LOOP_EXPR | MACRO_CALL | MATCH_EXPR
+            | IF_EXPR | INDEX_EXPR | LITERAL | LOOP_EXPR | MACRO_CALL | MACRO_STMTS
-            | METHOD_CALL_EXPR | PAREN_EXPR | PATH_EXPR | PREFIX_EXPR | RANGE_EXPR
+            | MATCH_EXPR | METHOD_CALL_EXPR | PAREN_EXPR | PATH_EXPR | PREFIX_EXPR | RANGE_EXPR
             | RECORD_EXPR | REF_EXPR | RETURN_EXPR | TRY_EXPR | TUPLE_EXPR | WHILE_EXPR
             | YIELD_EXPR => true,
             _ => false,
@@ -3105,6 +3109,7 @@ impl AstNode for Expr {
             LITERAL => Expr::Literal(Literal { syntax }),
             LOOP_EXPR => Expr::LoopExpr(LoopExpr { syntax }),
             MACRO_CALL => Expr::MacroCall(MacroCall { syntax }),
+            MACRO_STMTS => Expr::MacroStmts(MacroStmts { syntax }),
             MATCH_EXPR => Expr::MatchExpr(MatchExpr { syntax }),
             METHOD_CALL_EXPR => Expr::MethodCallExpr(MethodCallExpr { syntax }),
             PAREN_EXPR => Expr::ParenExpr(ParenExpr { syntax }),
@@ -3142,6 +3147,7 @@ impl AstNode for Expr {
             Expr::Literal(it) => &it.syntax,
             Expr::LoopExpr(it) => &it.syntax,
             Expr::MacroCall(it) => &it.syntax,
+            Expr::MacroStmts(it) => &it.syntax,
             Expr::MatchExpr(it) => &it.syntax,
             Expr::MethodCallExpr(it) => &it.syntax,
             Expr::ParenExpr(it) => &it.syntax,

xtask/Cargo.toml

@@ -11,7 +11,7 @@ anyhow = "1.0.26"
 flate2 = "1.0"
 proc-macro2 = "1.0.8"
 quote = "1.0.2"
-ungrammar = "=1.11"
+ungrammar = "=1.12"
 walkdir = "2.3.1"
 write-json = "0.1.0"
 xshell = "0.1"