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authorFlorian Diebold <[email protected]>2021-04-01 20:45:44 +0100
committerFlorian Diebold <[email protected]>2021-04-01 20:45:44 +0100
commit0e8c4503bf4754f4437d8bd45a110b9d0ec671e0 (patch)
tree0d09bc856ae7b8d5acc2dcc45226ea358dfa6412 /crates
parent25201b2dad7b4b0d41494e238ebf643ad7ad8cd6 (diff)
Don't recheck obligations if we have learned nothing new
This is just the most trivial check: If no inference variables have been updated, and there are no new obligations, we can just skip trying to solve them again. We could be smarter about it, but this already helps quite a bit, and I don't want to touch this too much before we replace the inference table by Chalk's. Fixes #8263 (well, improves it quite a bit).
Diffstat (limited to 'crates')
-rw-r--r--crates/hir_ty/src/infer.rs18
-rw-r--r--crates/hir_ty/src/infer/expr.rs6
-rw-r--r--crates/hir_ty/src/infer/path.rs2
-rw-r--r--crates/hir_ty/src/infer/unify.rs8
4 files changed, 26 insertions, 8 deletions
diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
index e4407ff50..497a1beb7 100644
--- a/crates/hir_ty/src/infer.rs
+++ b/crates/hir_ty/src/infer.rs
@@ -210,6 +210,7 @@ struct InferenceContext<'a> {
210 table: unify::InferenceTable, 210 table: unify::InferenceTable,
211 trait_env: Arc<TraitEnvironment>, 211 trait_env: Arc<TraitEnvironment>,
212 obligations: Vec<DomainGoal>, 212 obligations: Vec<DomainGoal>,
213 last_obligations_check: Option<u32>,
213 result: InferenceResult, 214 result: InferenceResult,
214 /// The return type of the function being inferred, or the closure if we're 215 /// The return type of the function being inferred, or the closure if we're
215 /// currently within one. 216 /// currently within one.
@@ -245,6 +246,7 @@ impl<'a> InferenceContext<'a> {
245 result: InferenceResult::default(), 246 result: InferenceResult::default(),
246 table: unify::InferenceTable::new(), 247 table: unify::InferenceTable::new(),
247 obligations: Vec::default(), 248 obligations: Vec::default(),
249 last_obligations_check: None,
248 return_ty: TyKind::Unknown.intern(&Interner), // set in collect_fn_signature 250 return_ty: TyKind::Unknown.intern(&Interner), // set in collect_fn_signature
249 trait_env: owner 251 trait_env: owner
250 .as_generic_def_id() 252 .as_generic_def_id()
@@ -334,6 +336,11 @@ impl<'a> InferenceContext<'a> {
334 } 336 }
335 337
336 fn resolve_obligations_as_possible(&mut self) { 338 fn resolve_obligations_as_possible(&mut self) {
339 if self.last_obligations_check == Some(self.table.revision) {
340 // no change
341 return;
342 }
343 self.last_obligations_check = Some(self.table.revision);
337 let obligations = mem::replace(&mut self.obligations, Vec::new()); 344 let obligations = mem::replace(&mut self.obligations, Vec::new());
338 for obligation in obligations { 345 for obligation in obligations {
339 let in_env = InEnvironment::new(self.trait_env.env.clone(), obligation.clone()); 346 let in_env = InEnvironment::new(self.trait_env.env.clone(), obligation.clone());
@@ -360,6 +367,11 @@ impl<'a> InferenceContext<'a> {
360 } 367 }
361 } 368 }
362 369
370 fn push_obligation(&mut self, o: DomainGoal) {
371 self.obligations.push(o);
372 self.last_obligations_check = None;
373 }
374
363 fn unify(&mut self, ty1: &Ty, ty2: &Ty) -> bool { 375 fn unify(&mut self, ty1: &Ty, ty2: &Ty) -> bool {
364 self.table.unify(ty1, ty2) 376 self.table.unify(ty1, ty2)
365 } 377 }
@@ -408,8 +420,8 @@ impl<'a> InferenceContext<'a> {
408 }), 420 }),
409 ty: ty.clone(), 421 ty: ty.clone(),
410 }; 422 };
411 self.obligations.push(trait_ref.cast(&Interner)); 423 self.push_obligation(trait_ref.cast(&Interner));
412 self.obligations.push(alias_eq.cast(&Interner)); 424 self.push_obligation(alias_eq.cast(&Interner));
413 self.resolve_ty_as_possible(ty) 425 self.resolve_ty_as_possible(ty)
414 } 426 }
415 None => self.err_ty(), 427 None => self.err_ty(),
@@ -436,7 +448,7 @@ impl<'a> InferenceContext<'a> {
436 let var = self.table.new_type_var(); 448 let var = self.table.new_type_var();
437 let alias_eq = AliasEq { alias: AliasTy::Projection(proj_ty), ty: var.clone() }; 449 let alias_eq = AliasEq { alias: AliasTy::Projection(proj_ty), ty: var.clone() };
438 let obligation = alias_eq.cast(&Interner); 450 let obligation = alias_eq.cast(&Interner);
439 self.obligations.push(obligation); 451 self.push_obligation(obligation);
440 var 452 var
441 } 453 }
442 454
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index 6279aa572..25ab3ea4c 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -99,7 +99,7 @@ impl<'a> InferenceContext<'a> {
99 environment: trait_env, 99 environment: trait_env,
100 }); 100 });
101 if self.db.trait_solve(krate, goal.value).is_some() { 101 if self.db.trait_solve(krate, goal.value).is_some() {
102 self.obligations.push(implements_fn_trait); 102 self.push_obligation(implements_fn_trait);
103 let output_proj_ty = crate::ProjectionTy { 103 let output_proj_ty = crate::ProjectionTy {
104 associated_ty_id: to_assoc_type_id(output_assoc_type), 104 associated_ty_id: to_assoc_type_id(output_assoc_type),
105 substitution: substs, 105 substitution: substs,
@@ -964,7 +964,7 @@ impl<'a> InferenceContext<'a> {
964 let (predicate, binders) = 964 let (predicate, binders) =
965 predicate.clone().subst(parameters).into_value_and_skipped_binders(); 965 predicate.clone().subst(parameters).into_value_and_skipped_binders();
966 always!(binders == 0); // quantified where clauses not yet handled 966 always!(binders == 0); // quantified where clauses not yet handled
967 self.obligations.push(predicate.cast(&Interner)); 967 self.push_obligation(predicate.cast(&Interner));
968 } 968 }
969 // add obligation for trait implementation, if this is a trait method 969 // add obligation for trait implementation, if this is a trait method
970 match def { 970 match def {
@@ -974,7 +974,7 @@ impl<'a> InferenceContext<'a> {
974 // construct a TraitRef 974 // construct a TraitRef
975 let substs = 975 let substs =
976 parameters.prefix(generics(self.db.upcast(), trait_.into()).len()); 976 parameters.prefix(generics(self.db.upcast(), trait_.into()).len());
977 self.obligations.push( 977 self.push_obligation(
978 TraitRef { trait_id: to_chalk_trait_id(trait_), substitution: substs } 978 TraitRef { trait_id: to_chalk_trait_id(trait_), substitution: substs }
979 .cast(&Interner), 979 .cast(&Interner),
980 ); 980 );
diff --git a/crates/hir_ty/src/infer/path.rs b/crates/hir_ty/src/infer/path.rs
index cefa38509..717738789 100644
--- a/crates/hir_ty/src/infer/path.rs
+++ b/crates/hir_ty/src/infer/path.rs
@@ -258,7 +258,7 @@ impl<'a> InferenceContext<'a> {
258 .push(ty.clone()) 258 .push(ty.clone())
259 .fill(std::iter::repeat_with(|| self.table.new_type_var())) 259 .fill(std::iter::repeat_with(|| self.table.new_type_var()))
260 .build(); 260 .build();
261 self.obligations.push( 261 self.push_obligation(
262 TraitRef { 262 TraitRef {
263 trait_id: to_chalk_trait_id(trait_), 263 trait_id: to_chalk_trait_id(trait_),
264 substitution: trait_substs.clone(), 264 substitution: trait_substs.clone(),
diff --git a/crates/hir_ty/src/infer/unify.rs b/crates/hir_ty/src/infer/unify.rs
index 6e7b0f5a6..5ea4b7481 100644
--- a/crates/hir_ty/src/infer/unify.rs
+++ b/crates/hir_ty/src/infer/unify.rs
@@ -231,6 +231,7 @@ pub(crate) struct TypeVariableData {
231pub(crate) struct InferenceTable { 231pub(crate) struct InferenceTable {
232 pub(super) var_unification_table: InPlaceUnificationTable<TypeVarId>, 232 pub(super) var_unification_table: InPlaceUnificationTable<TypeVarId>,
233 pub(super) type_variable_table: TypeVariableTable, 233 pub(super) type_variable_table: TypeVariableTable,
234 pub(super) revision: u32,
234} 235}
235 236
236impl InferenceTable { 237impl InferenceTable {
@@ -238,6 +239,7 @@ impl InferenceTable {
238 InferenceTable { 239 InferenceTable {
239 var_unification_table: InPlaceUnificationTable::new(), 240 var_unification_table: InPlaceUnificationTable::new(),
240 type_variable_table: TypeVariableTable { inner: Vec::new() }, 241 type_variable_table: TypeVariableTable { inner: Vec::new() },
242 revision: 0,
241 } 243 }
242 } 244 }
243 245
@@ -360,7 +362,10 @@ impl InferenceTable {
360 == self.type_variable_table.is_diverging(*tv2) => 362 == self.type_variable_table.is_diverging(*tv2) =>
361 { 363 {
362 // both type vars are unknown since we tried to resolve them 364 // both type vars are unknown since we tried to resolve them
363 self.var_unification_table.union(tv1.to_inner(), tv2.to_inner()); 365 if !self.var_unification_table.unioned(tv1.to_inner(), tv2.to_inner()) {
366 self.var_unification_table.union(tv1.to_inner(), tv2.to_inner());
367 self.revision += 1;
368 }
364 true 369 true
365 } 370 }
366 371
@@ -398,6 +403,7 @@ impl InferenceTable {
398 tv.to_inner(), 403 tv.to_inner(),
399 TypeVarValue::Known(other.clone().intern(&Interner)), 404 TypeVarValue::Known(other.clone().intern(&Interner)),
400 ); 405 );
406 self.revision += 1;
401 true 407 true
402 } 408 }
403 409