IRGen: Fix overly optimistic assumption in CanPackType::getSingletonPackExpansion()

slavapestov · slavapestov · commit da7149a18214 · 2023-04-20T13:44:32.000-04:00
diff --git a/lib/AST/ParameterPack.cpp b/lib/AST/ParameterPack.cpp
@@ -301,7 +301,12 @@ PackType *PackType::getSingletonPackExpansion(Type param) {
 }
 
 CanPackType CanPackType::getSingletonPackExpansion(CanType param) {
-  return CanPackType(PackType::getSingletonPackExpansion(param));
+  // Note: You can't just wrap the result in CanPackType() here because
+  // PackExpansionType has the additional requirement that the count type
+  // must be a reduced shape.
+  return cast<PackType>(
+    PackType::getSingletonPackExpansion(param)
+      ->getCanonicalType());
 }
 
 PackExpansionType *PackType::unwrapSingletonPackExpansion() const {

Original file line number	Diff line number	Diff line change
`@@ -301,7 +301,12 @@ PackType *PackType::getSingletonPackExpansion(Type param) {`
`301`	`301`	`}`
`302`	`302`
`303`	`303`	`CanPackType CanPackType::getSingletonPackExpansion(CanType param) {`
`304`		`- return CanPackType(PackType::getSingletonPackExpansion(param));`
	`304`	`+ // Note: You can't just wrap the result in CanPackType() here because`
	`305`	`+ // PackExpansionType has the additional requirement that the count type`
	`306`	`+ // must be a reduced shape.`
	`307`	`+ return cast<PackType>(`
	`308`	`+ PackType::getSingletonPackExpansion(param)`
	`309`	`+ ->getCanonicalType());`
`305`	`310`	`}`
`306`	`311`
`307`	`312`	`PackExpansionType *PackType::unwrapSingletonPackExpansion() const {`