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jroeschjroesch
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Remove second transaction
1 parent 3fd7f3a commit 0ad02ab

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1 file changed

+67
-57
lines changed
  • src/librustc_typeck/check

1 file changed

+67
-57
lines changed

‎src/librustc_typeck/check/mod.rs

Lines changed: 67 additions & 57 deletions
Original file line numberDiff line numberDiff line change
@@ -1778,43 +1778,49 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
17781778
// variable would only be in `unbound_tyvars` and have a concrete value if
17791779
// it had been solved by previously applying a default.
17801780

1781-
// We take a snapshot for use in error reporting.
1782-
let snapshot = self.infcx().start_snapshot();
1783-
1784-
for ty in &unbound_tyvars {
1785-
if self.infcx().type_var_diverges(ty) {
1786-
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().mk_nil());
1787-
} else {
1788-
match self.infcx().type_is_unconstrained_numeric(ty) {
1789-
UnconstrainedInt => {
1790-
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.i32)
1791-
},
1792-
UnconstrainedFloat => {
1793-
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.f64)
1794-
}
1795-
Neither => {
1796-
if let Some(default) = default_map.get(ty) {
1797-
let default = default.clone();
1798-
match infer::mk_eqty(self.infcx(), false,
1799-
infer::Misc(default.origin_span),
1800-
ty, default.ty) {
1801-
Ok(()) => {}
1802-
Err(_) => {
1803-
conflicts.push((*ty, default));
1781+
// We wrap this in a transaction for error reporting, if we detect a conflict
1782+
// we will rollback the inference context to its prior state so we can probe
1783+
// for conflicts and correctly report them.
1784+
let _ = self.infcx().commit_if_ok(|_: &infer::CombinedSnapshot| {
1785+
for ty in &unbound_tyvars {
1786+
if self.infcx().type_var_diverges(ty) {
1787+
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().mk_nil());
1788+
} else {
1789+
match self.infcx().type_is_unconstrained_numeric(ty) {
1790+
UnconstrainedInt => {
1791+
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.i32)
1792+
},
1793+
UnconstrainedFloat => {
1794+
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.f64)
1795+
}
1796+
Neither => {
1797+
if let Some(default) = default_map.get(ty) {
1798+
let default = default.clone();
1799+
match infer::mk_eqty(self.infcx(), false,
1800+
infer::Misc(default.origin_span),
1801+
ty, default.ty) {
1802+
Ok(()) => {}
1803+
Err(_) => {
1804+
conflicts.push((*ty, default));
1805+
}
18041806
}
18051807
}
18061808
}
18071809
}
18081810
}
18091811
}
1810-
}
18111812

1812-
// There are some errors to report
1813-
if conflicts.len() > 0 {
1814-
self.infcx().rollback_to(snapshot);
1813+
// If there are conflicts we rollback, otherwise commit
1814+
if conflicts.len() > 0 {
1815+
Err(())
1816+
} else {
1817+
Ok(())
1818+
}
1819+
});
18151820

1816-
// Loop through each conflicting default compute the conflict
1817-
// and then report the error.
1821+
if conflicts.len() > 0 {
1822+
// Loop through each conflicting default, figuring out the default that caused
1823+
// a unification failure and then report an error for each.
18181824
for (conflict, default) in conflicts {
18191825
let conflicting_default =
18201826
self.find_conflicting_default(
@@ -1826,13 +1832,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
18261832
definition_span: codemap::DUMMY_SP
18271833
});
18281834

1829-
self.infcx().report_conflicting_default_types(
1830-
conflicting_default.origin_span,
1831-
conflicting_default,
1832-
default)
1835+
self.infcx().report_conflicting_default_types(
1836+
conflicting_default.origin_span,
1837+
conflicting_default,
1838+
default)
18331839
}
1834-
} else {
1835-
self.infcx().commit_from(snapshot)
18361840
}
18371841
}
18381842

@@ -1850,41 +1854,47 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
18501854
-> Option<type_variable::Default<'tcx>> {
18511855
use middle::ty::UnconstrainedNumeric::{UnconstrainedInt, UnconstrainedFloat, Neither};
18521856

1853-
// Ensure that the conflicting default is applied first
1857+
// Ensure that we apply the conflicting default first
18541858
let mut unbound_tyvars = Vec::with_capacity(unbound_vars.len() + 1);
18551859
unbound_tyvars.push(conflict);
18561860
unbound_tyvars.extend(unbound_vars.iter());
18571861

18581862
let mut result = None;
18591863
// We run the same code as above applying defaults in order, this time when
18601864
// we find the conflict we just return it for error reporting above.
1861-
for ty in &unbound_tyvars {
1862-
if self.infcx().type_var_diverges(ty) {
1863-
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().mk_nil());
1864-
} else {
1865-
match self.infcx().type_is_unconstrained_numeric(ty) {
1866-
UnconstrainedInt => {
1867-
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.i32)
1868-
},
1869-
UnconstrainedFloat => {
1870-
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.f64)
1871-
},
1872-
Neither => {
1873-
if let Some(default) = default_map.get(ty) {
1874-
let default = default.clone();
1875-
match infer::mk_eqty(self.infcx(), false,
1876-
infer::Misc(default.origin_span),
1877-
ty, default.ty) {
1878-
Ok(()) => {}
1879-
Err(_) => {
1880-
result = Some(default);
1865+
1866+
// We also run this inside snapshot that never commits so we can do error
1867+
// reporting for more then one conflict.
1868+
//let _ = self.infcx().commit_if_ok(|_: &infer::CombinedSnapshot| {
1869+
for ty in &unbound_tyvars {
1870+
if self.infcx().type_var_diverges(ty) {
1871+
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().mk_nil());
1872+
} else {
1873+
match self.infcx().type_is_unconstrained_numeric(ty) {
1874+
UnconstrainedInt => {
1875+
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.i32)
1876+
},
1877+
UnconstrainedFloat => {
1878+
demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.f64)
1879+
},
1880+
Neither => {
1881+
if let Some(default) = default_map.get(ty) {
1882+
let default = default.clone();
1883+
match infer::mk_eqty(self.infcx(), false,
1884+
infer::Misc(default.origin_span),
1885+
ty, default.ty) {
1886+
Ok(()) => {}
1887+
Err(_) => {
1888+
result = Some(default);
1889+
}
18811890
}
18821891
}
18831892
}
18841893
}
18851894
}
18861895
}
1887-
}
1896+
// let result: Result<(), ()> = Err(()); result
1897+
//});
18881898

18891899
return result;
18901900
}

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