Rollup merge of #60901 - estebank:str-str-str, r=Centril
Handle more string addition cases with appropriate suggestions
This commit is contained in:
Manish Goregaokar
GitHub
commit
ba0e2518c8
@ -305,8 +305,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
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};
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if let Some(missing_trait) = missing_trait {
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if op.node == hir::BinOpKind::Add &&
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self.check_str_addition(expr, lhs_expr, rhs_expr, lhs_ty,
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rhs_ty, &mut err, true, op) {
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self.check_str_addition(
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lhs_expr, rhs_expr, lhs_ty, rhs_ty, &mut err, true, op) {
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// This has nothing here because it means we did string
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// concatenation (e.g., "Hello " += "World!"). This means
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// we don't want the note in the else clause to be emitted
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@ -400,8 +400,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
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};
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if let Some(missing_trait) = missing_trait {
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if op.node == hir::BinOpKind::Add &&
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self.check_str_addition(expr, lhs_expr, rhs_expr, lhs_ty,
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rhs_ty, &mut err, false, op) {
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self.check_str_addition(
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lhs_expr, rhs_expr, lhs_ty, rhs_ty, &mut err, false, op) {
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// This has nothing here because it means we did string
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// concatenation (e.g., "Hello " + "World!"). This means
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// we don't want the note in the else clause to be emitted
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@ -502,9 +502,13 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
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false
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}
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/// Provide actionable suggestions when trying to add two strings with incorrect types,
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/// like `&str + &str`, `String + String` and `&str + &String`.
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///
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/// If this function returns `true` it means a note was printed, so we don't need
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/// to print the normal "implementation of `std::ops::Add` might be missing" note
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fn check_str_addition(
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&self,
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expr: &'gcx hir::Expr,
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lhs_expr: &'gcx hir::Expr,
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rhs_expr: &'gcx hir::Expr,
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lhs_ty: Ty<'tcx>,
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@ -514,45 +518,78 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
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op: hir::BinOp,
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) -> bool {
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let source_map = self.tcx.sess.source_map();
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let remove_borrow_msg = "String concatenation appends the string on the right to the \
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string on the left and may require reallocation. This \
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requires ownership of the string on the left";
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let msg = "`to_owned()` can be used to create an owned `String` \
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from a string reference. String concatenation \
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appends the string on the right to the string \
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on the left and may require reallocation. This \
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requires ownership of the string on the left";
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// If this function returns true it means a note was printed, so we don't need
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// to print the normal "implementation of `std::ops::Add` might be missing" note
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let is_std_string = |ty| &format!("{:?}", ty) == "std::string::String";
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match (&lhs_ty.sty, &rhs_ty.sty) {
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(&Ref(_, l_ty, _), &Ref(_, r_ty, _))
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if l_ty.sty == Str && r_ty.sty == Str => {
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if !is_assign {
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err.span_label(op.span,
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"`+` can't be used to concatenate two `&str` strings");
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(&Ref(_, l_ty, _), &Ref(_, r_ty, _)) // &str or &String + &str, &String or &&str
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if (l_ty.sty == Str || is_std_string(l_ty)) && (
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r_ty.sty == Str || is_std_string(r_ty) ||
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&format!("{:?}", rhs_ty) == "&&str"
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) =>
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{
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if !is_assign { // Do not supply this message if `&str += &str`
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err.span_label(
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op.span,
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"`+` cannot be used to concatenate two `&str` strings",
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);
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match source_map.span_to_snippet(lhs_expr.span) {
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Ok(lstring) => err.span_suggestion(
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lhs_expr.span,
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msg,
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format!("{}.to_owned()", lstring),
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Applicability::MachineApplicable,
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),
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Ok(lstring) => {
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err.span_suggestion(
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lhs_expr.span,
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if lstring.starts_with("&") {
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remove_borrow_msg
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} else {
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msg
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},
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if lstring.starts_with("&") {
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// let a = String::new();
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// let _ = &a + "bar";
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format!("{}", &lstring[1..])
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} else {
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format!("{}.to_owned()", lstring)
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},
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Applicability::MachineApplicable,
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)
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}
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_ => err.help(msg),
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};
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}
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true
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}
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(&Ref(_, l_ty, _), &Adt(..))
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if l_ty.sty == Str && &format!("{:?}", rhs_ty) == "std::string::String" => {
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err.span_label(expr.span,
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"`+` can't be used to concatenate a `&str` with a `String`");
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(&Ref(_, l_ty, _), &Adt(..)) // Handle `&str` & `&String` + `String`
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if (l_ty.sty == Str || is_std_string(l_ty)) && is_std_string(rhs_ty) =>
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{
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err.span_label(
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op.span,
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"`+` cannot be used to concatenate a `&str` with a `String`",
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);
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match (
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source_map.span_to_snippet(lhs_expr.span),
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source_map.span_to_snippet(rhs_expr.span),
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is_assign,
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) {
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(Ok(l), Ok(r), false) => {
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let to_string = if l.starts_with("&") {
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// let a = String::new(); let b = String::new();
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// let _ = &a + b;
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format!("{}", &l[1..])
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} else {
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format!("{}.to_owned()", l)
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};
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err.multipart_suggestion(
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msg,
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vec![
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(lhs_expr.span, format!("{}.to_owned()", l)),
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(lhs_expr.span, to_string),
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(rhs_expr.span, format!("&{}", r)),
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],
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Applicability::MachineApplicable,
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@ -3497,8 +3497,7 @@ impl<'a> Parser<'a> {
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let binary = self.mk_binary(source_map::respan(cur_op_span, ast_op), lhs, rhs);
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self.mk_expr(span, binary, ThinVec::new())
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}
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AssocOp::Assign =>
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self.mk_expr(span, ExprKind::Assign(lhs, rhs), ThinVec::new()),
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AssocOp::Assign => self.mk_expr(span, ExprKind::Assign(lhs, rhs), ThinVec::new()),
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AssocOp::ObsoleteInPlace =>
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self.mk_expr(span, ExprKind::ObsoleteInPlace(lhs, rhs), ThinVec::new()),
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AssocOp::AssignOp(k) => {
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@ -4,7 +4,7 @@ error[E0369]: binary operation `+` cannot be applied to type `&str`
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LL | let _a = b + ", World!";
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| - ^ ---------- &str
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| | |
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| | `+` can't be used to concatenate two `&str` strings
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| | `+` cannot be used to concatenate two `&str` strings
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| &str
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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@ -4,7 +4,7 @@ error[E0369]: binary operation `+` cannot be applied to type `&str`
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LL | println!("🦀🦀🦀🦀🦀"); let _a = b + ", World!";
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| - ^ ---------- &str
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| | |
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| | `+` can't be used to concatenate two `&str` strings
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| | `+` cannot be used to concatenate two `&str` strings
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| &str
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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@ -16,3 +16,23 @@ enum World {
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Hello,
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Goodbye,
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}
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fn foo() {
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let a = String::new();
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let b = String::new();
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let c = "";
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let d = "";
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let e = &a;
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let _ = &a + &b; //~ ERROR binary operation
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let _ = &a + b; //~ ERROR binary operation
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let _ = a + &b; // ok
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let _ = a + b; //~ ERROR mismatched types
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let _ = e + b; //~ ERROR binary operation
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let _ = e + &b; //~ ERROR binary operation
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let _ = e + d; //~ ERROR binary operation
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let _ = e + &d; //~ ERROR binary operation
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let _ = &c + &d; //~ ERROR binary operation
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let _ = &c + d; //~ ERROR binary operation
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let _ = c + &d; //~ ERROR binary operation
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let _ = c + d; //~ ERROR binary operation
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}
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@ -4,7 +4,7 @@ error[E0369]: binary operation `+` cannot be applied to type `&str`
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LL | let x = "Hello " + "World!";
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| -------- ^ -------- &str
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| | |
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| | `+` can't be used to concatenate two `&str` strings
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| | `+` cannot be used to concatenate two `&str` strings
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| &str
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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@ -25,16 +25,152 @@ error[E0369]: binary operation `+` cannot be applied to type `&str`
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--> $DIR/issue-39018.rs:11:22
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LL | let x = "Hello " + "World!".to_owned();
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| ---------^--------------------
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| | |
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| | std::string::String
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| -------- ^ ------------------- std::string::String
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| | |
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| | `+` cannot be used to concatenate a `&str` with a `String`
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| &str
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| `+` can't be used to concatenate a `&str` with a `String`
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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|
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LL | let x = "Hello ".to_owned() + &"World!".to_owned();
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| ^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^
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error: aborting due to 3 previous errors
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error[E0369]: binary operation `+` cannot be applied to type `&std::string::String`
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--> $DIR/issue-39018.rs:26:16
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LL | let _ = &a + &b;
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| -- ^ -- &std::string::String
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| | |
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| | `+` cannot be used to concatenate two `&str` strings
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| &std::string::String
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help: String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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|
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LL | let _ = a + &b;
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| ^
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For more information about this error, try `rustc --explain E0369`.
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error[E0369]: binary operation `+` cannot be applied to type `&std::string::String`
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--> $DIR/issue-39018.rs:27:16
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|
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LL | let _ = &a + b;
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| -- ^ - std::string::String
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| | |
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| | `+` cannot be used to concatenate a `&str` with a `String`
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| &std::string::String
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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|
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LL | let _ = a + &b;
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| ^ ^^
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error[E0308]: mismatched types
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--> $DIR/issue-39018.rs:29:17
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LL | let _ = a + b;
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| ^
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| |
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| expected &str, found struct `std::string::String`
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| help: consider borrowing here: `&b`
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= note: expected type `&str`
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found type `std::string::String`
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error[E0369]: binary operation `+` cannot be applied to type `&std::string::String`
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--> $DIR/issue-39018.rs:30:15
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|
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LL | let _ = e + b;
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| - ^ - std::string::String
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| | |
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| | `+` cannot be used to concatenate a `&str` with a `String`
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| &std::string::String
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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|
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LL | let _ = e.to_owned() + &b;
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| ^^^^^^^^^^^^ ^^
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error[E0369]: binary operation `+` cannot be applied to type `&std::string::String`
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--> $DIR/issue-39018.rs:31:15
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|
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LL | let _ = e + &b;
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| - ^ -- &std::string::String
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| | |
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| | `+` cannot be used to concatenate two `&str` strings
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| &std::string::String
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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|
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LL | let _ = e.to_owned() + &b;
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| ^^^^^^^^^^^^
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error[E0369]: binary operation `+` cannot be applied to type `&std::string::String`
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--> $DIR/issue-39018.rs:32:15
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|
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LL | let _ = e + d;
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| - ^ - &str
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| | |
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| | `+` cannot be used to concatenate two `&str` strings
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| &std::string::String
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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|
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LL | let _ = e.to_owned() + d;
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| ^^^^^^^^^^^^
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error[E0369]: binary operation `+` cannot be applied to type `&std::string::String`
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--> $DIR/issue-39018.rs:33:15
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|
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LL | let _ = e + &d;
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| - ^ -- &&str
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| | |
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| | `+` cannot be used to concatenate two `&str` strings
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| &std::string::String
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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|
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LL | let _ = e.to_owned() + &d;
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| ^^^^^^^^^^^^
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error[E0369]: binary operation `+` cannot be applied to type `&&str`
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--> $DIR/issue-39018.rs:34:16
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|
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LL | let _ = &c + &d;
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| -- ^ -- &&str
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| |
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| &&str
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|
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= note: an implementation of `std::ops::Add` might be missing for `&&str`
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error[E0369]: binary operation `+` cannot be applied to type `&&str`
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--> $DIR/issue-39018.rs:35:16
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|
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LL | let _ = &c + d;
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| -- ^ - &str
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| |
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| &&str
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|
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= note: an implementation of `std::ops::Add` might be missing for `&&str`
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error[E0369]: binary operation `+` cannot be applied to type `&str`
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--> $DIR/issue-39018.rs:36:15
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|
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LL | let _ = c + &d;
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| - ^ -- &&str
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| | |
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| | `+` cannot be used to concatenate two `&str` strings
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| &str
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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|
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LL | let _ = c.to_owned() + &d;
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| ^^^^^^^^^^^^
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error[E0369]: binary operation `+` cannot be applied to type `&str`
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--> $DIR/issue-39018.rs:37:15
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|
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LL | let _ = c + d;
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| - ^ - &str
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| | |
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| | `+` cannot be used to concatenate two `&str` strings
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| &str
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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|
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LL | let _ = c.to_owned() + d;
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| ^^^^^^^^^^^^
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error: aborting due to 14 previous errors
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Some errors have detailed explanations: E0308, E0369.
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For more information about an error, try `rustc --explain E0308`.
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@ -3,10 +3,13 @@ error[E0369]: binary operation `+` cannot be applied to type `&std::string::Stri
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|
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LL | let c = a + b;
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| - ^ - &str
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| |
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| | |
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| | `+` cannot be used to concatenate two `&str` strings
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| &std::string::String
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help: `to_owned()` can be used to create an owned `String` from a string reference. String concatenation appends the string on the right to the string on the left and may require reallocation. This requires ownership of the string on the left
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|
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= note: an implementation of `std::ops::Add` might be missing for `&std::string::String`
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LL | let c = a.to_owned() + b;
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| ^^^^^^^^^^^^
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error: aborting due to previous error
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