diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs index 2ac1a036f99e1..726c305e90304 100644 --- a/src/librustc/hir/lowering.rs +++ b/src/librustc/hir/lowering.rs @@ -907,6 +907,13 @@ impl<'a> LoweringContext<'a> { FunctionRetTy::Default(span) => hir::DefaultReturn(span), }, variadic: decl.variadic, + has_implicit_self: decl.inputs.get(0).map_or(false, |arg| { + match arg.ty.node { + TyKind::ImplicitSelf => true, + TyKind::Rptr(_, ref mt) => mt.ty.node == TyKind::ImplicitSelf, + _ => false + } + }) }) } diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs index 1c79a02d3da0e..43b7deb5b90e3 100644 --- a/src/librustc/hir/mod.rs +++ b/src/librustc/hir/mod.rs @@ -1379,6 +1379,9 @@ pub struct FnDecl { pub inputs: HirVec>, pub output: FunctionRetTy, pub variadic: bool, + /// True if this function has an `self`, `&self` or `&mut self` receiver + /// (but not a `self: Xxx` one). + pub has_implicit_self: bool, } #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)] diff --git a/src/librustc_borrowck/borrowck/mod.rs b/src/librustc_borrowck/borrowck/mod.rs index 0981369ace5c1..558a835be1884 100644 --- a/src/librustc_borrowck/borrowck/mod.rs +++ b/src/librustc_borrowck/borrowck/mod.rs @@ -42,7 +42,6 @@ use std::fmt; use std::rc::Rc; use std::hash::{Hash, Hasher}; use syntax::ast; -use syntax::symbol::keywords; use syntax_pos::{MultiSpan, Span}; use errors::DiagnosticBuilder; @@ -809,32 +808,33 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { } /// Given a type, if it is an immutable reference, return a suggestion to make it mutable - fn suggest_mut_for_immutable(&self, pty: &hir::Ty) -> Option { + fn suggest_mut_for_immutable(&self, pty: &hir::Ty, is_implicit_self: bool) -> Option { // Check wether the argument is an immutable reference + debug!("suggest_mut_for_immutable({:?}, {:?})", pty, is_implicit_self); if let hir::TyRptr(lifetime, hir::MutTy { mutbl: hir::Mutability::MutImmutable, ref ty }) = pty.node { // Account for existing lifetimes when generating the message - if !lifetime.is_elided() { - if let Ok(snippet) = self.tcx.sess.codemap().span_to_snippet(ty.span) { - if let Ok(lifetime_snippet) = self.tcx.sess.codemap() - .span_to_snippet(lifetime.span) { - return Some(format!("use `&{} mut {}` here to make mutable", - lifetime_snippet, - snippet)); - } - } - } else if let Ok(snippet) = self.tcx.sess.codemap().span_to_snippet(pty.span) { - if snippet.starts_with("&") { - return Some(format!("use `{}` here to make mutable", - snippet.replace("&", "&mut "))); - } + let pointee_snippet = match self.tcx.sess.codemap().span_to_snippet(ty.span) { + Ok(snippet) => snippet, + _ => return None + }; + + let lifetime_snippet = if !lifetime.is_elided() { + format!("{} ", match self.tcx.sess.codemap().span_to_snippet(lifetime.span) { + Ok(lifetime_snippet) => lifetime_snippet, + _ => return None + }) } else { - bug!("couldn't find a snippet for span: {:?}", pty.span); - } + String::new() + }; + Some(format!("use `&{}mut {}` here to make mutable", + lifetime_snippet, + if is_implicit_self { "self" } else { &*pointee_snippet })) + } else { + None } - None } fn local_binding_mode(&self, node_id: ast::NodeId) -> hir::BindingMode { @@ -849,7 +849,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { } } - fn local_ty(&self, node_id: ast::NodeId) -> Option<&hir::Ty> { + fn local_ty(&self, node_id: ast::NodeId) -> (Option<&hir::Ty>, bool) { let parent = self.tcx.hir.get_parent_node(node_id); let parent_node = self.tcx.hir.get(parent); @@ -857,16 +857,17 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { if let Some(fn_like) = FnLikeNode::from_node(parent_node) { // `nid`'s parent's `Body` let fn_body = self.tcx.hir.body(fn_like.body()); - // Get the position of `nid` in the arguments list + // Get the position of `node_id` in the arguments list let arg_pos = fn_body.arguments.iter().position(|arg| arg.pat.id == node_id); if let Some(i) = arg_pos { // The argument's `Ty` - Some(&fn_like.decl().inputs[i]) + (Some(&fn_like.decl().inputs[i]), + i == 0 && fn_like.decl().has_implicit_self) } else { - None + (None, false) } } else { - None + (None, false) } } @@ -880,8 +881,8 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { let let_span = self.tcx.hir.span(node_id); if let hir::BindingMode::BindByValue(..) = self.local_binding_mode(node_id) { if let Ok(snippet) = self.tcx.sess.codemap().span_to_snippet(let_span) { - if self.tcx.hir.name(node_id) == keywords::SelfValue.name() && - snippet != "self" { + let (_, is_implicit_self) = self.local_ty(node_id); + if is_implicit_self && snippet != "self" { // avoid suggesting `mut &self`. return } @@ -906,8 +907,9 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { } } hir::BindingMode::BindByValue(..) => { - if let Some(local_ty) = self.local_ty(node_id) { - if let Some(msg) = self.suggest_mut_for_immutable(local_ty) { + if let (Some(local_ty), is_implicit_self) = self.local_ty(node_id) { + if let Some(msg) = + self.suggest_mut_for_immutable(local_ty, is_implicit_self) { db.span_label(local_ty.span, &msg); } } @@ -921,7 +923,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { }; if let hir_map::Node::NodeField(ref field) = self.tcx.hir.get(node_id) { - if let Some(msg) = self.suggest_mut_for_immutable(&field.ty) { + if let Some(msg) = self.suggest_mut_for_immutable(&field.ty, false) { db.span_label(field.ty.span, &msg); } } diff --git a/src/test/ui/did_you_mean/issue-39544.rs b/src/test/ui/did_you_mean/issue-39544.rs index c98fed3c3c3c7..6331fc5771fcb 100644 --- a/src/test/ui/did_you_mean/issue-39544.rs +++ b/src/test/ui/did_you_mean/issue-39544.rs @@ -16,11 +16,37 @@ pub struct Z { x: X } -pub fn main() { +fn main() { let z = Z { x: X::Y }; let _ = &mut z.x; } +impl Z { + fn foo<'z>(&'z self) { + let _ = &mut self.x; + } + + fn foo1(&self, other: &Z) { + let _ = &mut self.x; + let _ = &mut other.x; + } + + fn foo2<'a>(&'a self, other: &Z) { + let _ = &mut self.x; + let _ = &mut other.x; + } + + fn foo3<'a>(self: &'a Self, other: &Z) { + let _ = &mut self.x; + let _ = &mut other.x; + } + + fn foo4(other: &Z) { + let _ = &mut other.x; + } + +} + pub fn with_arg(z: Z, w: &Z) { let _ = &mut z.x; let _ = &mut w.x; diff --git a/src/test/ui/did_you_mean/issue-39544.stderr b/src/test/ui/did_you_mean/issue-39544.stderr index bcd55fd744bb6..e1e229a8b0572 100644 --- a/src/test/ui/did_you_mean/issue-39544.stderr +++ b/src/test/ui/did_you_mean/issue-39544.stderr @@ -6,22 +6,89 @@ error: cannot borrow immutable field `z.x` as mutable 21 | let _ = &mut z.x; | ^^^ cannot mutably borrow immutable field +error: cannot borrow immutable field `self.x` as mutable + --> $DIR/issue-39544.rs:26:22 + | +25 | fn foo<'z>(&'z self) { + | -------- use `&'z mut self` here to make mutable +26 | let _ = &mut self.x; + | ^^^^^^ cannot mutably borrow immutable field + +error: cannot borrow immutable field `self.x` as mutable + --> $DIR/issue-39544.rs:30:22 + | +29 | fn foo1(&self, other: &Z) { + | ----- use `&mut self` here to make mutable +30 | let _ = &mut self.x; + | ^^^^^^ cannot mutably borrow immutable field + +error: cannot borrow immutable field `other.x` as mutable + --> $DIR/issue-39544.rs:31:22 + | +29 | fn foo1(&self, other: &Z) { + | -- use `&mut Z` here to make mutable +30 | let _ = &mut self.x; +31 | let _ = &mut other.x; + | ^^^^^^^ cannot mutably borrow immutable field + +error: cannot borrow immutable field `self.x` as mutable + --> $DIR/issue-39544.rs:35:22 + | +34 | fn foo2<'a>(&'a self, other: &Z) { + | -------- use `&'a mut self` here to make mutable +35 | let _ = &mut self.x; + | ^^^^^^ cannot mutably borrow immutable field + +error: cannot borrow immutable field `other.x` as mutable + --> $DIR/issue-39544.rs:36:22 + | +34 | fn foo2<'a>(&'a self, other: &Z) { + | -- use `&mut Z` here to make mutable +35 | let _ = &mut self.x; +36 | let _ = &mut other.x; + | ^^^^^^^ cannot mutably borrow immutable field + +error: cannot borrow immutable field `self.x` as mutable + --> $DIR/issue-39544.rs:40:22 + | +39 | fn foo3<'a>(self: &'a Self, other: &Z) { + | -------- use `&'a mut Self` here to make mutable +40 | let _ = &mut self.x; + | ^^^^^^ cannot mutably borrow immutable field + +error: cannot borrow immutable field `other.x` as mutable + --> $DIR/issue-39544.rs:41:22 + | +39 | fn foo3<'a>(self: &'a Self, other: &Z) { + | -- use `&mut Z` here to make mutable +40 | let _ = &mut self.x; +41 | let _ = &mut other.x; + | ^^^^^^^ cannot mutably borrow immutable field + +error: cannot borrow immutable field `other.x` as mutable + --> $DIR/issue-39544.rs:45:22 + | +44 | fn foo4(other: &Z) { + | -- use `&mut Z` here to make mutable +45 | let _ = &mut other.x; + | ^^^^^^^ cannot mutably borrow immutable field + error: cannot borrow immutable field `z.x` as mutable - --> $DIR/issue-39544.rs:25:18 + --> $DIR/issue-39544.rs:51:18 | -24 | pub fn with_arg(z: Z, w: &Z) { +50 | pub fn with_arg(z: Z, w: &Z) { | - consider changing this to `mut z` -25 | let _ = &mut z.x; +51 | let _ = &mut z.x; | ^^^ cannot mutably borrow immutable field error: cannot borrow immutable field `w.x` as mutable - --> $DIR/issue-39544.rs:26:18 + --> $DIR/issue-39544.rs:52:18 | -24 | pub fn with_arg(z: Z, w: &Z) { +50 | pub fn with_arg(z: Z, w: &Z) { | -- use `&mut Z` here to make mutable -25 | let _ = &mut z.x; -26 | let _ = &mut w.x; +51 | let _ = &mut z.x; +52 | let _ = &mut w.x; | ^^^ cannot mutably borrow immutable field -error: aborting due to 3 previous errors +error: aborting due to 11 previous errors