Pass down the substitutions of the original pattern when extracting

a subst abstraction pattern from a generic nominal type.

Author: rjmccall

lib/SIL/IR/AbstractionPattern.cpp

@@ -1961,8 +1961,11 @@ class SubstFunctionTypePatternVisitor
       : CanType(CanMetatypeType::get(substInstance));
   }
 
-  CanType handleGenericNominalType(CanType orig, CanType subst,
-                                   CanGenericSignature origSig) {
+  CanType handleGenericNominalType(AbstractionPattern origPattern, CanType subst) {
+    CanType orig = origPattern.getType();
+    CanGenericSignature origSig = origPattern.getGenericSignatureOrNull();
+    auto origPatternSubs = origPattern.getGenericSubstitutions();
+
     // If there are no loose type parameters in the pattern here, we don't need
     // to do a recursive visit at all.
     if (!orig->hasTypeParameter()
@@ -2007,6 +2010,7 @@ class SubstFunctionTypePatternVisitor
     if (differentOrigClass) {
       orig = subst;
       origSig = TC.getCurGenericSignature();
+      origPatternSubs = SubstitutionMap();
       assert((!subst->hasTypeParameter() || origSig) &&
              "lowering mismatched interface types in a context without "
              "a generic signature");
@@ -2028,7 +2032,8 @@ class SubstFunctionTypePatternVisitor
         ->getCanonicalType();
 
       replacementTypes[gp->getCanonicalType()->castTo<SubstitutableType>()]
-          = visit(substParamTy, AbstractionPattern(origSig, origParamTy));
+          = visit(substParamTy,
+                  AbstractionPattern(origPatternSubs, origSig, origParamTy));
     }
 
     auto newSubMap = SubstitutionMap::get(nomGenericSig,
@@ -2048,8 +2053,7 @@ class SubstFunctionTypePatternVisitor
     // If the type is generic (because it's a nested type in a generic context),
     // process the generic type bindings.
     if (!isa<ProtocolDecl>(nomDecl) && nomDecl->isGenericContext()) {
-      return handleGenericNominalType(pattern.getType(), nom,
-                                      pattern.getGenericSignatureOrNull());
+      return handleGenericNominalType(pattern, nom);
     }
 
     // Otherwise, there are no structural type parameters to visit.
@@ -2058,8 +2062,7 @@ class SubstFunctionTypePatternVisitor
 
   CanType visitBoundGenericType(CanBoundGenericType bgt,
                                 AbstractionPattern pattern) {
-    return handleGenericNominalType(pattern.getType(), bgt,
-                                    pattern.getGenericSignatureOrNull());
+    return handleGenericNominalType(pattern, bgt);
   }
 
   CanType visitPackType(CanPackType pack, AbstractionPattern pattern) {
@@ -2085,7 +2088,7 @@ class SubstFunctionTypePatternVisitor
     // the pack substitution for that parameter recorded in the pattern.
 
     // Remember that we're within an expansion.
-    // FIXME: when we introduce PackReferenceType we'll need to be clear
+    // FIXME: when we introduce PackElementType we'll need to be clear
     // about which pack expansions to treat this way.
     llvm::SaveAndRestore<bool> scope(WithinExpansion, true);
 

test/SILGen/variadic-generic-closures.swift

@@ -9,3 +9,9 @@ public struct G<T> {}
 public func caller<each T>(fn: (repeat G<each T>) -> ()) {
   fn(repeat G<each T>())
 }
+
+// rdar://107108803
+public struct UsesG<each Input> {
+  public init<E>(builder: (repeat G<each Input>) -> E) {}
+}
+UsesG<Int, String, Bool> { a, b, c in 0 }