diff --git a/src/librustc_resolve/late.rs b/src/librustc_resolve/late.rs index a0d59fa4829e8..325921b59823a 100644 --- a/src/librustc_resolve/late.rs +++ b/src/librustc_resolve/late.rs @@ -345,7 +345,7 @@ struct DiagnosticMetadata { /// The current self item if inside an ADT (used for better errors). current_self_item: Option, - /// The current enclosing funciton (used for better errors). + /// The current enclosing function (used for better errors). current_function: Option, /// A list of labels as of yet unused. Labels will be removed from this map when diff --git a/src/librustc_resolve/late/diagnostics.rs b/src/librustc_resolve/late/diagnostics.rs index 5e59efac53647..3a6bb37269ff0 100644 --- a/src/librustc_resolve/late/diagnostics.rs +++ b/src/librustc_resolve/late/diagnostics.rs @@ -259,6 +259,24 @@ impl<'a> LateResolutionVisitor<'a, '_> { } return (err, candidates); } + + // If the first argument in call is `self` suggest calling a method. + if let Some((call_span, args_span)) = self.call_has_self_arg(source) { + let mut args_snippet = String::new(); + if let Some(args_span) = args_span { + if let Ok(snippet) = self.r.session.source_map().span_to_snippet(args_span) { + args_snippet = snippet; + } + } + + err.span_suggestion( + call_span, + &format!("try calling `{}` as a method", ident), + format!("self.{}({})", path_str, args_snippet), + Applicability::MachineApplicable, + ); + return (err, candidates); + } } // Try Levenshtein algorithm. @@ -298,6 +316,43 @@ impl<'a> LateResolutionVisitor<'a, '_> { (err, candidates) } + /// Check if the source is call expression and the first argument is `self`. If true, + /// return the span of whole call and the span for all arguments expect the first one (`self`). + fn call_has_self_arg(&self, source: PathSource<'_>) -> Option<(Span, Option)> { + let mut has_self_arg = None; + if let PathSource::Expr(parent) = source { + match &parent?.kind { + ExprKind::Call(_, args) if args.len() > 0 => { + let mut expr_kind = &args[0].kind; + loop { + match expr_kind { + ExprKind::Path(_, arg_name) if arg_name.segments.len() == 1 => { + if arg_name.segments[0].ident.name == kw::SelfLower { + let call_span = parent.unwrap().span; + let tail_args_span = if args.len() > 1 { + Some(Span::new( + args[1].span.lo(), + args.last().unwrap().span.hi(), + call_span.ctxt(), + )) + } else { + None + }; + has_self_arg = Some((call_span, tail_args_span)); + } + break; + } + ExprKind::AddrOf(_, _, expr) => expr_kind = &expr.kind, + _ => break, + } + } + } + _ => (), + } + }; + return has_self_arg; + } + fn followed_by_brace(&self, span: Span) -> (bool, Option<(Span, String)>) { // HACK(estebank): find a better way to figure out that this was a // parser issue where a struct literal is being used on an expression diff --git a/src/test/ui/self/suggest-self-2.rs b/src/test/ui/self/suggest-self-2.rs new file mode 100644 index 0000000000000..d6bf543352701 --- /dev/null +++ b/src/test/ui/self/suggest-self-2.rs @@ -0,0 +1,25 @@ +struct Foo {} + +impl Foo { + fn foo(&self) { + bar(self); + //~^ ERROR cannot find function `bar` in this scope + //~| HELP try calling `bar` as a method + + bar(&&self, 102); + //~^ ERROR cannot find function `bar` in this scope + //~| HELP try calling `bar` as a method + + bar(&mut self, 102, &"str"); + //~^ ERROR cannot find function `bar` in this scope + //~| HELP try calling `bar` as a method + + bar(); + //~^ ERROR cannot find function `bar` in this scope + + self.bar(); + //~^ ERROR no method named `bar` found for type + } +} + +fn main() {} diff --git a/src/test/ui/self/suggest-self-2.stderr b/src/test/ui/self/suggest-self-2.stderr new file mode 100644 index 0000000000000..452c31275153a --- /dev/null +++ b/src/test/ui/self/suggest-self-2.stderr @@ -0,0 +1,40 @@ +error[E0425]: cannot find function `bar` in this scope + --> $DIR/suggest-self-2.rs:5:9 + | +LL | bar(self); + | ^^^------ + | | + | help: try calling `bar` as a method: `self.bar()` + +error[E0425]: cannot find function `bar` in this scope + --> $DIR/suggest-self-2.rs:9:9 + | +LL | bar(&&self, 102); + | ^^^------------- + | | + | help: try calling `bar` as a method: `self.bar(102)` + +error[E0425]: cannot find function `bar` in this scope + --> $DIR/suggest-self-2.rs:13:9 + | +LL | bar(&mut self, 102, &"str"); + | ^^^------------------------ + | | + | help: try calling `bar` as a method: `self.bar(102, &"str")` + +error[E0425]: cannot find function `bar` in this scope + --> $DIR/suggest-self-2.rs:17:9 + | +LL | bar(); + | ^^^ not found in this scope + +error[E0599]: no method named `bar` found for type `&Foo` in the current scope + --> $DIR/suggest-self-2.rs:20:14 + | +LL | self.bar(); + | ^^^ method not found in `&Foo` + +error: aborting due to 5 previous errors + +Some errors have detailed explanations: E0425, E0599. +For more information about an error, try `rustc --explain E0425`.