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Auto merge of #50986 - estebank:main-start-span, r=nikomatsakis
Tweak `main` type arguments and where clause spans Tweak the spans for error when finding type arguments or where clauses in main and start functions.
2 parents c8e10e3 + b2562fb commit 7942022

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8 files changed

+55
-37
lines changed

8 files changed

+55
-37
lines changed

‎src/librustc/hir/mod.rs

+12
Original file line numberDiff line numberDiff line change
@@ -598,6 +598,18 @@ pub struct WhereClause {
598598
pub predicates: HirVec<WherePredicate>,
599599
}
600600

601+
impl WhereClause {
602+
pub fn span(&self) -> Option<Span> {
603+
self.predicates.iter().map(|predicate| predicate.span())
604+
.fold(None, |acc, i| match (acc, i) {
605+
(None, i) => Some(i),
606+
(Some(acc), i) => {
607+
Some(acc.to(i))
608+
}
609+
})
610+
}
611+
}
612+
601613
/// A single predicate in a `where` clause
602614
#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
603615
pub enum WherePredicate {

‎src/librustc_typeck/lib.rs

+26-16
Original file line numberDiff line numberDiff line change
@@ -186,18 +186,23 @@ fn check_main_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
186186
Some(hir_map::NodeItem(it)) => {
187187
match it.node {
188188
hir::ItemFn(.., ref generics, _) => {
189+
let mut error = false;
189190
if !generics.params.is_empty() {
190191
struct_span_err!(tcx.sess, generics.span, E0131,
191-
"main function is not allowed to have type parameters")
192+
"`main` function is not allowed to have type parameters")
192193
.span_label(generics.span,
193-
"main cannot have type parameters")
194+
"`main` cannot have type parameters")
194195
.emit();
195-
return;
196+
error = true;
197+
}
198+
if let Some(sp) = generics.where_clause.span() {
199+
struct_span_err!(tcx.sess, sp, E0646,
200+
"`main` function is not allowed to have a `where` clause")
201+
.span_label(sp, "`main` cannot have a `where` clause")
202+
.emit();
203+
error = true;
196204
}
197-
if !generics.where_clause.predicates.is_empty() {
198-
struct_span_err!(tcx.sess, main_span, E0646,
199-
"main function is not allowed to have a where clause")
200-
.emit();
205+
if error {
201206
return;
202207
}
203208
}
@@ -251,19 +256,24 @@ fn check_start_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
251256
match tcx.hir.find(start_id) {
252257
Some(hir_map::NodeItem(it)) => {
253258
match it.node {
254-
hir::ItemFn(..,ref ps,_) => {
255-
if !ps.params.is_empty() {
256-
struct_span_err!(tcx.sess, ps.span, E0132,
259+
hir::ItemFn(.., ref generics, _) => {
260+
let mut error = false;
261+
if !generics.params.is_empty() {
262+
struct_span_err!(tcx.sess, generics.span, E0132,
257263
"start function is not allowed to have type parameters")
258-
.span_label(ps.span,
264+
.span_label(generics.span,
259265
"start function cannot have type parameters")
260266
.emit();
261-
return;
267+
error = true;
268+
}
269+
if let Some(sp) = generics.where_clause.span() {
270+
struct_span_err!(tcx.sess, sp, E0647,
271+
"start function is not allowed to have a `where` clause")
272+
.span_label(sp, "start function cannot have a `where` clause")
273+
.emit();
274+
error = true;
262275
}
263-
if !ps.where_clause.predicates.is_empty() {
264-
struct_span_err!(tcx.sess, start_span, E0647,
265-
"start function is not allowed to have a where clause")
266-
.emit();
276+
if error {
267277
return;
268278
}
269279
}

‎src/test/compile-fail/issue-1900.rs

+1-1
Original file line numberDiff line numberDiff line change
@@ -8,5 +8,5 @@
88
// option. This file may not be copied, modified, or distributed
99
// except according to those terms.
1010

11-
// error-pattern: main function is not allowed to have type parameters
11+
// error-pattern: `main` function is not allowed to have type parameters
1212
fn main<T>() { }

‎src/test/ui/error-codes/E0131.stderr

+2-2
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,8 @@
1-
error[E0131]: main function is not allowed to have type parameters
1+
error[E0131]: `main` function is not allowed to have type parameters
22
--> $DIR/E0131.rs:11:8
33
|
44
LL | fn main<T>() {
5-
| ^^^ main cannot have type parameters
5+
| ^^^ `main` cannot have type parameters
66

77
error: aborting due to previous error
88

‎src/test/ui/error-codes/E0646.stderr

+3-3
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,8 @@
1-
error[E0646]: main function is not allowed to have a where clause
2-
--> $DIR/E0646.rs:11:1
1+
error[E0646]: `main` function is not allowed to have a `where` clause
2+
--> $DIR/E0646.rs:11:17
33
|
44
LL | fn main() where (): Copy {} //~ ERROR [E0646]
5-
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
5+
| ^^^^^^^^ `main` cannot have a `where` clause
66

77
error: aborting due to previous error
88

‎src/test/ui/error-codes/E0647.stderr

+4-6
Original file line numberDiff line numberDiff line change
@@ -1,10 +1,8 @@
1-
error[E0647]: start function is not allowed to have a where clause
2-
--> $DIR/E0647.rs:17:1
1+
error[E0647]: start function is not allowed to have a `where` clause
2+
--> $DIR/E0647.rs:17:56
33
|
4-
LL | / fn start(_: isize, _: *const *const u8) -> isize where (): Copy { //~ ERROR [E0647]
5-
LL | | 0
6-
LL | | }
7-
| |_^
4+
LL | fn start(_: isize, _: *const *const u8) -> isize where (): Copy { //~ ERROR [E0647]
5+
| ^^^^^^^^ start function cannot have a `where` clause
86

97
error: aborting due to previous error
108

‎src/test/ui/issue-50714-1.stderr

+4-6
Original file line numberDiff line numberDiff line change
@@ -1,10 +1,8 @@
1-
error[E0647]: start function is not allowed to have a where clause
2-
--> $DIR/issue-50714-1.rs:19:1
1+
error[E0647]: start function is not allowed to have a `where` clause
2+
--> $DIR/issue-50714-1.rs:19:56
33
|
4-
LL | / fn start(_: isize, _: *const *const u8) -> isize where fn(&()): Eq { //~ ERROR [E0647]
5-
LL | | 0
6-
LL | | }
7-
| |_^
4+
LL | fn start(_: isize, _: *const *const u8) -> isize where fn(&()): Eq { //~ ERROR [E0647]
5+
| ^^^^^^^^^^^ start function cannot have a `where` clause
86

97
error: aborting due to previous error
108

‎src/test/ui/issue-50714.stderr

+3-3
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,8 @@
1-
error[E0646]: main function is not allowed to have a where clause
2-
--> $DIR/issue-50714.rs:13:1
1+
error[E0646]: `main` function is not allowed to have a `where` clause
2+
--> $DIR/issue-50714.rs:13:17
33
|
44
LL | fn main() where fn(&()): Eq {} //~ ERROR [E0646]
5-
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
5+
| ^^^^^^^^^^^ `main` cannot have a `where` clause
66

77
error: aborting due to previous error
88

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