add start_stmt to handle postfix increment

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -1259,10 +1259,9 @@ impl<'a> Parser<'a> {
         &mut self,
         operand_expr: P<Expr>,
         op_span: Span,
-        prev_is_semi: bool,
+        start_stmt: bool,
     ) -> PResult<'a, P<Expr>> {
-        let standalone =
-            if prev_is_semi { IsStandalone::Standalone } else { IsStandalone::Subexpr };
+        let standalone = if start_stmt { IsStandalone::Standalone } else { IsStandalone::Subexpr };
         let kind = IncDecRecovery { standalone, op: IncOrDec::Inc, fixity: UnaryFixity::Pre };
         self.recover_from_inc_dec(operand_expr, kind, op_span)
     }
@@ -1271,10 +1270,10 @@ impl<'a> Parser<'a> {
         &mut self,
         operand_expr: P<Expr>,
         op_span: Span,
-        prev_is_semi: bool,
+        start_stmt: bool,
     ) -> PResult<'a, P<Expr>> {
         let kind = IncDecRecovery {
-            standalone: if prev_is_semi { IsStandalone::Standalone } else { IsStandalone::Subexpr },
+            standalone: if start_stmt { IsStandalone::Standalone } else { IsStandalone::Subexpr },
             op: IncOrDec::Inc,
             fixity: UnaryFixity::Post,
         };
@@ -1305,20 +1304,22 @@ impl<'a> Parser<'a> {
             UnaryFixity::Post => (base.span.shrink_to_lo(), op_span),
         };
 
-        let Ok(base_src) = self.span_to_snippet(base.span)
-        else { return help_base_case(err, base) };
         match kind.standalone {
             IsStandalone::Standalone => {
                 self.inc_dec_standalone_suggest(kind, spans).emit_verbose(&mut err)
             }
-            IsStandalone::Subexpr => match kind.fixity {
-                UnaryFixity::Pre => {
-                    self.prefix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
+            IsStandalone::Subexpr => {
+                let Ok(base_src) = self.span_to_snippet(base.span)
+                else { return help_base_case(err, base) };
+                match kind.fixity {
+                    UnaryFixity::Pre => {
+                        self.prefix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
+                    }
+                    UnaryFixity::Post => {
+                        self.postfix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
+                    }
                 }
-                UnaryFixity::Post => {
-                    self.postfix_inc_dec_suggest(base_src, kind, spans).emit(&mut err)
-                }
-            },
+            }
         }
         Err(err)
     }

compiler/rustc_parse/src/parser/expr.rs

@@ -83,7 +83,7 @@ macro_rules! maybe_whole_expr {
 pub(super) enum LhsExpr {
     NotYetParsed,
     AttributesParsed(AttrWrapper),
-    AlreadyParsed(P<Expr>),
+    AlreadyParsed(P<Expr>, bool), // (expr, starts_statement)
 }
 
 impl From<Option<AttrWrapper>> for LhsExpr {
@@ -101,7 +101,7 @@ impl From<P<Expr>> for LhsExpr {
     ///
     /// This conversion does not allocate.
     fn from(expr: P<Expr>) -> Self {
-        LhsExpr::AlreadyParsed(expr)
+        LhsExpr::AlreadyParsed(expr, false)
     }
 }
 
@@ -173,7 +173,9 @@ impl<'a> Parser<'a> {
         min_prec: usize,
         lhs: LhsExpr,
     ) -> PResult<'a, P<Expr>> {
-        let mut lhs = if let LhsExpr::AlreadyParsed(expr) = lhs {
+        let mut starts_stmt = false;
+        let mut lhs = if let LhsExpr::AlreadyParsed(expr, starts_statement) = lhs {
+            starts_stmt = starts_statement;
             expr
         } else {
             let attrs = match lhs {
@@ -292,15 +294,7 @@ impl<'a> Parser<'a> {
                 let op_span = self.prev_token.span.to(self.token.span);
                 // Eat the second `+`
                 self.bump();
-                let prev_is_semi = {
-                    if let Ok(prev_code) = self.sess.source_map().span_to_prev_source(lhs.span) &&
-                          prev_code.trim_end().ends_with(";") {
-                            true
-                    } else {
-                        false
-                    }
-                };
-                lhs = self.recover_from_postfix_increment(lhs, op_span, prev_is_semi)?;
+                lhs = self.recover_from_postfix_increment(lhs, op_span, starts_stmt)?;
                 continue;
             }
 
@@ -607,14 +601,15 @@ impl<'a> Parser<'a> {
             token::BinOp(token::Plus)
                 if this.look_ahead(1, |t| *t == token::BinOp(token::Plus)) =>
             {
-                let prev_is_semi = this.prev_token == token::Semi;
+                let starts_stmt = this.prev_token == token::Semi
+                    || this.prev_token == token::CloseDelim(Delimiter::Brace);
                 let pre_span = this.token.span.to(this.look_ahead(1, |t| t.span));
                 // Eat both `+`s.
                 this.bump();
                 this.bump();
 
                 let operand_expr = this.parse_dot_or_call_expr(Default::default())?;
-                this.recover_from_prefix_increment(operand_expr, pre_span, prev_is_semi)
+                this.recover_from_prefix_increment(operand_expr, pre_span, starts_stmt)
             }
             token::Ident(..) if this.token.is_keyword(kw::Box) => {
                 make_it!(this, attrs, |this, _| this.parse_box_expr(lo))

compiler/rustc_parse/src/parser/stmt.rs

@@ -156,7 +156,7 @@ impl<'a> Parser<'a> {
             // Perform this outside of the `collect_tokens_trailing_token` closure,
             // since our outer attributes do not apply to this part of the expression
             let expr = self.with_res(Restrictions::STMT_EXPR, |this| {
-                this.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(expr))
+                this.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(expr, true))
             })?;
             Ok(self.mk_stmt(lo.to(self.prev_token.span), StmtKind::Expr(expr)))
         } else {
@@ -190,7 +190,7 @@ impl<'a> Parser<'a> {
             let e = self.mk_expr(lo.to(hi), ExprKind::MacCall(mac));
             let e = self.maybe_recover_from_bad_qpath(e)?;
             let e = self.parse_dot_or_call_expr_with(e, lo, attrs)?;
-            let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e))?;
+            let e = self.parse_assoc_expr_with(0, LhsExpr::AlreadyParsed(e, false))?;
             StmtKind::Expr(e)
         };
         Ok(self.mk_stmt(lo.to(hi), kind))

src/test/ui/parser/increment-autofix-2.stderr

@@ -1,5 +1,5 @@
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:13:6
+  --> $DIR/increment-autofix-2.rs:13:6
    |
 LL |     i++;
    |      ^^ not a valid postfix operator
@@ -10,7 +10,7 @@ LL |     i += 1;
    |       ~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:19:12
+  --> $DIR/increment-autofix-2.rs:19:12
    |
 LL |     while i++ < 5 {
    |     -----  ^^ not a valid postfix operator
@@ -23,7 +23,7 @@ LL |     while { let tmp = i; i += 1; tmp } < 5 {
    |           +++++++++++  ~~~~~~~~~~~~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:27:8
+  --> $DIR/increment-autofix-2.rs:27:8
    |
 LL |     tmp++;
    |        ^^ not a valid postfix operator
@@ -34,7 +34,7 @@ LL |     tmp += 1;
    |         ~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:33:14
+  --> $DIR/increment-autofix-2.rs:33:14
    |
 LL |     while tmp++ < 5 {
    |     -----    ^^ not a valid postfix operator
@@ -47,7 +47,7 @@ LL |     while { let tmp_ = tmp; tmp += 1; tmp_ } < 5 {
    |           ++++++++++++    ~~~~~~~~~~~~~~~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:41:16
+  --> $DIR/increment-autofix-2.rs:41:16
    |
 LL |     foo.bar.qux++;
    |                ^^ not a valid postfix operator
@@ -58,7 +58,7 @@ LL |     foo.bar.qux += 1;
    |                 ~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:51:10
+  --> $DIR/increment-autofix-2.rs:51:10
    |
 LL |     s.tmp++;
    |          ^^ not a valid postfix operator
@@ -69,7 +69,7 @@ LL |     s.tmp += 1;
    |           ~~~~
 
 error: Rust has no prefix increment operator
-  --> $DIR/increment-notfixed.rs:58:5
+  --> $DIR/increment-autofix-2.rs:58:5
    |
 LL |     ++foo.bar.qux;
    |     ^^ not a valid prefix operator

src/test/ui/parser/issue-104867-inc-dec-2.rs

@@ -0,0 +1,41 @@
+fn test1() {
+    let mut i = 0;
+    let _ = i + ++i; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test2() {
+    let mut i = 0;
+    let _ = ++i + i; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test3() {
+    let mut i = 0;
+    let _ = ++i + ++i; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test4() {
+    let mut i = 0;
+    let _ = i + i++; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test5() {
+    let mut i = 0;
+    let _ = i++ + i; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test6() {
+    let mut i = 0;
+    let _ = i++ + i++; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test7() {
+    let mut i = 0;
+    let _ = ++i + i++; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test8() {
+    let mut i = 0;
+    let _ = i++ + ++i; //~ ERROR Rust has no postfix increment operator
+}
+
+fn main() { }

src/test/ui/parser/issue-104867-inc-dec-2.stderr

@@ -0,0 +1,90 @@
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:3:17
+   |
+LL |     let _ = i + ++i;
+   |                 ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = i + { i += 1; i };
+   |                 ~   +++++++++
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:8:13
+   |
+LL |     let _ = ++i + i;
+   |             ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { i += 1; i } + i;
+   |             ~   +++++++++
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:13:13
+   |
+LL |     let _ = ++i + ++i;
+   |             ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { i += 1; i } + ++i;
+   |             ~   +++++++++
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:18:18
+   |
+LL |     let _ = i + i++;
+   |                  ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i + i; i + i += 1; tmp };
+   |             +++++++++++      ~~~~~~~~~~~~~~~~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:23:14
+   |
+LL |     let _ = i++ + i;
+   |              ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i; i += 1; tmp } + i;
+   |             +++++++++++  ~~~~~~~~~~~~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:28:14
+   |
+LL |     let _ = i++ + i++;
+   |              ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i; i += 1; tmp } + i++;
+   |             +++++++++++  ~~~~~~~~~~~~~~~
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:33:13
+   |
+LL |     let _ = ++i + i++;
+   |             ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { i += 1; i } + i++;
+   |             ~   +++++++++
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:38:14
+   |
+LL |     let _ = i++ + ++i;
+   |              ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i; i += 1; tmp } + ++i;
+   |             +++++++++++  ~~~~~~~~~~~~~~~
+
+error: aborting due to 8 previous errors
+

src/test/ui/parser/issue-104867-inc-dec.rs

@@ -27,4 +27,19 @@ fn test5() {
     if ++i == 1 { } //~ ERROR Rust has no prefix increment operator
 }
 
+fn test6() {
+    let mut i = 0;
+    loop { break; }
+    i++; //~ ERROR Rust has no postfix increment operator
+    loop { break; }
+    ++i;
+}
+
+fn test7() {
+    let mut i = 0;
+    loop { break; }
+    ++i; //~ ERROR Rust has no prefix increment operator
+}
+
+
 fn main() {}

src/test/ui/parser/issue-104867-inc-dec.stderr

@@ -54,5 +54,28 @@ help: use `+= 1` instead
 LL |     if { i += 1; i } == 1 { }
    |        ~   +++++++++
 
-error: aborting due to 5 previous errors
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:33:6
+   |
+LL |     i++;
+   |      ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     i += 1;
+   |       ~~~~
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:41:5
+   |
+LL |     ++i;
+   |     ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL -     ++i;
+LL +     i += 1;
+   |
+
+error: aborting due to 7 previous errors