SIL: Compute canonical type earlier

Author: slavapestov

lib/SIL/IR/SILFunctionType.cpp

@@ -2012,22 +2012,22 @@ lowerCaptureContextParameters(TypeConverter &TC, SILDeclRef function,
 
     auto options = SILParameterInfo::Options();
 
-    Type type;
+    CanType type;
     VarDecl *varDecl = nullptr;
     if (auto *expr = capture.getPackElement()) {
-      type = expr->getType();
+      type = expr->getType()->getCanonicalType();
     } else {
       varDecl = cast<VarDecl>(capture.getDecl());
-      type = varDecl->getTypeInContext();
+      type = varDecl->getTypeInContext()->getCanonicalType();
 
       // If we're capturing a parameter pack, wrap it in a tuple.
-      if (type->is<PackExpansionType>()) {
+      if (isa<PackExpansionType>(type)) {
         assert(!cast<ParamDecl>(varDecl)->supportsMutation() &&
                "Cannot capture a pack as an lvalue");
 
         SmallVector<TupleTypeElt, 1> elts;
         elts.push_back(type);
-        type = TupleType::get(elts, TC.Context);
+        type = CanType(TupleType::get(elts, TC.Context));
       }
 
       if (isolatedParam == varDecl) {

test/SILGen/phantom_existential_typealias.swift

@@ -18,3 +18,10 @@ protocol P {
 func test1(p: any P) -> [Int] {
   return p.x.f { $0.y }
 }
+
+func callee(_: () -> ()) {}
+
+func test2(p: any P) {
+  let a = p.x
+  callee { _ = a }
+}