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Use callsite's span for macro calls on suggestion
When suggesting an appropriate mutability for a macro call, use the call
span instead of the expanded macro's span.
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estebank committed Jun 1, 2017
1 parent 4ed2eda commit 4142d7b
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Showing 6 changed files with 36 additions and 7 deletions.
8 changes: 3 additions & 5 deletions src/librustc_errors/emitter.rs
Expand Up @@ -705,11 +705,9 @@ impl EmitterWriter {
if *sp == DUMMY_SP {
continue;
}
if cm.span_to_filename(sp.clone()).contains("macros>") {
let v = sp.macro_backtrace();
if let Some(use_site) = v.last() {
before_after.push((sp.clone(), use_site.call_site.clone()));
}
let call_sp = cm.call_span_if_macro(*sp);
if call_sp != *sp {
before_after.push((sp.clone(), call_sp));
}
for trace in sp.macro_backtrace().iter().rev() {
// Only show macro locations that are local
Expand Down
1 change: 1 addition & 0 deletions src/librustc_errors/lib.rs
Expand Up @@ -102,6 +102,7 @@ pub trait CodeMapper {
fn span_to_string(&self, sp: Span) -> String;
fn span_to_filename(&self, sp: Span) -> FileName;
fn merge_spans(&self, sp_lhs: Span, sp_rhs: Span) -> Option<Span>;
fn call_span_if_macro(&self, sp: Span) -> Span;
}

impl CodeSuggestion {
Expand Down
6 changes: 4 additions & 2 deletions src/librustc_typeck/check/demand.rs
Expand Up @@ -18,7 +18,7 @@ use syntax_pos::{self, Span};
use rustc::hir;
use rustc::hir::def::Def;
use rustc::ty::{self, Ty, AssociatedItem};
use errors::DiagnosticBuilder;
use errors::{DiagnosticBuilder, CodeMapper};

use super::method::probe;

Expand Down Expand Up @@ -187,7 +187,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
checked_ty),
};
if self.can_coerce(ref_ty, expected) {
if let Ok(src) = self.tcx.sess.codemap().span_to_snippet(expr.span) {
// Use the callsite's span if this is a macro call. #41858
let sp = self.sess().codemap().call_span_if_macro(expr.span);
if let Ok(src) = self.tcx.sess.codemap().span_to_snippet(sp) {
return Some(format!("try with `{}{}`",
match mutability.mutbl {
hir::Mutability::MutMutable => "&mut ",
Expand Down
9 changes: 9 additions & 0 deletions src/libsyntax/codemap.rs
Expand Up @@ -563,6 +563,15 @@ impl CodeMapper for CodeMap {
fn merge_spans(&self, sp_lhs: Span, sp_rhs: Span) -> Option<Span> {
self.merge_spans(sp_lhs, sp_rhs)
}
fn call_span_if_macro(&self, sp: Span) -> Span {
if self.span_to_filename(sp.clone()).contains("macros>") {
let v = sp.macro_backtrace();
if let Some(use_site) = v.last() {
return use_site.call_site;
}
}
sp
}
}

#[derive(Clone)]
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8 changes: 8 additions & 0 deletions src/test/ui/span/coerce-suggestions.rs
Expand Up @@ -43,4 +43,12 @@ fn main() {
//~| NOTE cyclic type of infinite size
//~| NOTE expected type `_`
//~| NOTE found type `Box<_>`

let s = &mut String::new();
s = format!("foo");
//~^ ERROR E0308
//~| NOTE expected mutable reference, found struct `std::string::String`
//~| NOTE expected type `&mut std::string::String`
//~| HELP try with `&mut format!("foo")`
//~| NOTE this error originates in a macro outside of the current crate
}
11 changes: 11 additions & 0 deletions src/test/ui/span/coerce-suggestions.stderr
Expand Up @@ -47,5 +47,16 @@ error[E0308]: mismatched types
= note: expected type `_`
found type `std::boxed::Box<_>`

error[E0308]: mismatched types
--> $DIR/coerce-suggestions.rs:48:9
|
48 | s = format!("foo");
| ^^^^^^^^^^^^^^ expected mutable reference, found struct `std::string::String`
|
= note: expected type `&mut std::string::String`
found type `std::string::String`
= help: try with `&mut format!("foo")`
= note: this error originates in a macro outside of the current crate

error: aborting due to previous error(s)

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