[GSB] Centralize diagnosis of concrete types and conformance requirem…

…ents. Ensures that we don't admit invalid cases where the concrete type does not conform to the required protocol.
DougGregor · Jun 24, 2017 · c879b95 · c879b95
1 parent 791ac7f
commit c879b95
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Showing 2 changed files with 28 additions and 18 deletions.
diff --git a/lib/AST/GenericSignatureBuilder.cpp b/lib/AST/GenericSignatureBuilder.cpp
@@ -1326,15 +1326,6 @@ GenericSignatureBuilder::resolveConcreteConformance(PotentialArchetype *pa,
   auto concrete = pa->getConcreteType();
   if (!concrete) return nullptr;
 
-  // Lookup the conformance of the concrete type to this protocol.
-  auto conformance =
-    getLookupConformanceFn()(pa->getDependentType({ }, /*allowUnresolved=*/true)
-                               ->getCanonicalType(),
-                             concrete,
-                             proto->getDeclaredInterfaceType()
-                              ->castTo<ProtocolType>());
-  if (!conformance) return nullptr;
-
   // Conformance to this protocol is redundant; update the requirement source
   // appropriately.
   auto paEquivClass = pa->getOrCreateEquivalenceClass();
@@ -1345,6 +1336,23 @@ GenericSignatureBuilder::resolveConcreteConformance(PotentialArchetype *pa,
   else
     concreteSource = paEquivClass->concreteTypeConstraints.front().source;
 
+  // Lookup the conformance of the concrete type to this protocol.
+  auto conformance =
+    getLookupConformanceFn()(pa->getDependentType({ }, /*allowUnresolved=*/true)
+                               ->getCanonicalType(),
+                             concrete,
+                             proto->getDeclaredInterfaceType()
+                              ->castTo<ProtocolType>());
+  if (!conformance) {
+    if (!concrete->hasError() && concreteSource->getLoc().isValid()) {
+      Diags.diagnose(concreteSource->getLoc(),
+                     diag::requires_generic_param_same_type_does_not_conform,
+                     concrete, proto->getName());
+    }
+
+    return nullptr;
+  }
+
   concreteSource = concreteSource->viaConcrete(*this, *conformance);
   paEquivClass->conformsTo[proto].push_back({pa, proto, concreteSource});
   ++NumConformanceConstraints;
@@ -3454,15 +3462,8 @@ ConstraintResult GenericSignatureBuilder::addSameTypeRequirementToConcrete(
   // Make sure the concrete type fulfills the conformance requirements of
   // this equivalence class.
   for (auto protocol : rep->getConformsTo()) {
-    if (!resolveConcreteConformance(rep, protocol)) {
-      if (!Concrete->hasError() && Source->getLoc().isValid()) {
-        Diags.diagnose(Source->getLoc(),
-                       diag::requires_generic_param_same_type_does_not_conform,
-                       Concrete, protocol->getName());
-      }
-
+    if (!resolveConcreteConformance(rep, protocol))
       return ConstraintResult::Conflicting;
-    }
   }
 
   // Eagerly resolve any existing nested types to their concrete forms (others

diff --git a/test/Constraints/same_types.swift b/test/Constraints/same_types.swift
@@ -88,7 +88,7 @@ func test6<T: Barrable>(_ t: T) -> (Y, X) where T.Bar == Y {
 
 func test7<T: Barrable>(_ t: T) -> (Y, X) where T.Bar == Y, T.Bar.Foo == X {
 	// expected-warning@-1{{redundant same-type constraint 'T.Bar.Foo' == 'X'}}
-	// expected-note@-2{{same-type constraint 'T.Bar.Foo' == 'Y.Foo' (aka 'X') implied here}}
+        // expected-note@-2{{same-type constraint 'T.Bar.Foo' == 'Y.Foo' (aka 'X') implied here}}
   return (t.bar, t.bar.foo)
 }
 
@@ -241,5 +241,14 @@ func structuralSameTypeRecursive1<T: P2, U>(_: T, _: U)
 { }
 
 
+protocol P3 {
+}
+
+protocol P4 {
+  associatedtype A
+}
+
+func test9<T>(_: T) where T.A == X, T: P4, T.A: P3 { } // expected-error{{same-type constraint type 'X' does not conform to required protocol 'P3'}}
+
 // FIXME: Remove -verify-ignore-unknown.
 // <unknown>:0: error: unexpected error produced: generic parameter τ_0_0.Bar.Foo cannot be equal to both 'Y.Foo' (aka 'X') and 'Z'