[swift-settings] Provide a default nullptr for a variable.

gottesmm · gottesmm · commit cd38b7846625 · 2025-03-17T13:17:20.000-07:00
Just noticed it as I was reading some code. Even though it cannot happen today,
with code being added, we could allow for undefined behavior. Better to program
defensively than aggressively.
diff --git a/lib/AST/Module.cpp b/lib/AST/Module.cpp
@@ -4345,7 +4345,7 @@ SwiftSettingsWalker::getSwiftSettingArgDecl(Argument arg) {
     return {};
 
   // Now lookup our swiftSettingDecl.
-  NominalTypeDecl *swiftSettingsDecl;
+  NominalTypeDecl *swiftSettingsDecl = nullptr;
   {
     SmallVector<ValueDecl *, 1> decls;
     ctx.lookupInSwiftModule("SwiftSetting", decls);

Original file line number	Diff line number	Diff line change
`@@ -4345,7 +4345,7 @@ SwiftSettingsWalker::getSwiftSettingArgDecl(Argument arg) {`
`4345`	`4345`	`return {};`
`4346`	`4346`
`4347`	`4347`	`// Now lookup our swiftSettingDecl.`
`4348`		`- NominalTypeDecl *swiftSettingsDecl;`
	`4348`	`+ NominalTypeDecl *swiftSettingsDecl = nullptr;`
`4349`	`4349`	`{`
`4350`	`4350`	`SmallVector<ValueDecl *, 1> decls;`
`4351`	`4351`	`ctx.lookupInSwiftModule("SwiftSetting", decls);`