[ConstraintSystem] Fix a crash related to function conversion reliant on conditional conformance

Author: theblixguy

lib/Sema/CSDiagnostics.cpp

@@ -175,8 +175,7 @@ ProtocolConformance *RequirementFailure::getConformanceForConditionalReq(
     return nullptr;
   }
 
-  auto *typeReqLoc = cs.getConstraintLocator(getRawAnchor(), path.drop_back(),
-                                             /*summaryFlags=*/0);
+  auto *typeReqLoc = getConstraintLocator(getRawAnchor(), path.drop_back());
 
   auto result = llvm::find_if(
       cs.CheckedConformances,
@@ -1758,8 +1757,7 @@ bool MissingCallFailure::diagnoseAsError() {
 
     case ConstraintLocator::AutoclosureResult: {
       auto &cs = getConstraintSystem();
-      auto loc = cs.getConstraintLocator(getRawAnchor(), path.drop_back(),
-                                         /*summaryFlags=*/0);
+      auto loc = getConstraintLocator(getRawAnchor(), path.drop_back());
       AutoClosureForwardingFailure failure(cs, loc);
       return failure.diagnoseAsError();
     }

lib/Sema/CSDiagnostics.h

@@ -145,6 +145,14 @@ class FailureDiagnostic {
     return nullptr;
   }
 
+  /// Retrive the constraint locator for the given anchor and
+  /// path, uniqued and automatically calculate the summary flags
+  ConstraintLocator *
+  getConstraintLocator(Expr *anchor,
+                       ArrayRef<ConstraintLocator::PathElement> path) {
+    return CS.getConstraintLocator(anchor, path);
+  }
+
   /// \returns true is locator hasn't been simplified down to expression.
   bool hasComplexLocator() const { return HasComplexLocator; }
 

lib/Sema/CSSimplify.cpp

@@ -2001,13 +2001,11 @@ static ConstraintFix *fixRequirementFailure(ConstraintSystem &cs, Type type1,
     auto reqPath = path.drop_back();
     // If underlying conformance requirement has been fixed,
     // then there is no reason to fix up conditional requirements.
-    if (cs.hasFixFor(cs.getConstraintLocator(anchor, reqPath,
-                                             /*summaryFlags=*/0)))
+    if (cs.hasFixFor(cs.getConstraintLocator(anchor, reqPath)))
       return nullptr;
   }
 
-  auto *reqLoc = cs.getConstraintLocator(anchor, path,
-                                         /*summaryFlags=*/0);
+  auto *reqLoc = cs.getConstraintLocator(anchor, path);
 
   auto reqKind = static_cast<RequirementKind>(req.getValue2());
   switch (reqKind) {
@@ -2169,8 +2167,7 @@ bool ConstraintSystem::repairFailures(
                                       getASTContext().TheEmptyTupleType);
       conversionsOrFixes.push_back(AddMissingArguments::create(
           *this, fnType, {FunctionType::Param(*arg)},
-          getConstraintLocator(anchor, path,
-                               /*summaryFlags=*/0)));
+          getConstraintLocator(anchor, path)));
     }
     break;
   }

lib/Sema/CSStep.cpp

@@ -313,8 +313,8 @@ StepResult ComponentStep::take(bool prevFailed) {
       // Let's drop `generic parameter '...'` part of the locator to
       // group all of the missing generic parameters related to the
       // same path together.
-      defaultableGenericParams[CS.getConstraintLocator(anchor, path.drop_back(),
-                                                       /*summaryFlags=*/0)]
+      defaultableGenericParams[CS.getConstraintLocator(anchor,
+                                                       path.drop_back())]
           .push_back(locator->getGenericParameter());
     }
 

lib/Sema/ConstraintSystem.cpp

@@ -374,6 +374,12 @@ getAlternativeLiteralTypes(KnownProtocolKind kind) {
   return *AlternativeLiteralTypes[index];
 }
 
+ConstraintLocator *ConstraintSystem::getConstraintLocator(
+    Expr *anchor, ArrayRef<ConstraintLocator::PathElement> path) {
+  auto summaryFlags = ConstraintLocator::getSummaryFlagsForPath(path);
+  return getConstraintLocator(anchor, path, summaryFlags);
+}
+
 ConstraintLocator *ConstraintSystem::getConstraintLocator(
                      Expr *anchor,
                      ArrayRef<ConstraintLocator::PathElement> path,

lib/Sema/ConstraintSystem.h

@@ -1888,6 +1888,12 @@ class ConstraintSystem {
                        ArrayRef<ConstraintLocator::PathElement> path,
                        unsigned summaryFlags);
 
+  /// Retrive the constraint locator for the given anchor and
+  /// path, uniqued and automatically infer the summary flags
+  ConstraintLocator *
+  getConstraintLocator(Expr *anchor,
+                       ArrayRef<ConstraintLocator::PathElement> path);
+
   /// Retrieve the constraint locator for the given anchor and
   /// an empty path, uniqued.
   ConstraintLocator *getConstraintLocator(Expr *anchor) {

test/Generics/conditional_conformances.swift

@@ -402,3 +402,14 @@ extension BinaryInteger {
             // expected-error@-1 {{referencing instance method 'reduce' on 'ClosedRange' requires that 'Self.Stride' conform to 'SignedInteger'}}
   }
 }
+
+// SR-10992
+
+protocol SR_10992_P {}
+struct SR_10992_S<T> {}
+extension SR_10992_S: SR_10992_P where T: SR_10992_P {} // expected-note {{requirement from conditional conformance of 'SR_10992_S<String>' to 'SR_10992_P'}}
+	
+func sr_10992_foo(_ fn: (SR_10992_S<String>) -> Void) {}
+func sr_10992_bar(_ fn: (SR_10992_P) -> Void) {
+  sr_10992_foo(fn) // expected-error {{global function 'sr_10992_foo' requires that 'String' conform to 'SR_10992_P'}}
+}

validation-test/compiler_crashers_2_fixed/sr10992.swift

@@ -0,0 +1,10 @@
+// RUN: not %target-swift-frontend -typecheck %s
+
+protocol P {}
+struct S<T> {}
+extension S : P where T : P {}
+
+func foo(_ fn: (S<String>) -> Void) {}
+func bar(_ fn: (P) -> Void) {
+  foo(fn)
+}