Sema: Fix crash in diagnoseIfSynthesisUnsupportedForDecl() with tuple extension

slavapestov · slavapestov · commit 0fae4cb5cd4f · 2025-06-16T19:46:57.000-04:00
diff --git a/lib/Sema/DerivedConformance/DerivedConformance.cpp b/lib/Sema/DerivedConformance/DerivedConformance.cpp
@@ -272,6 +272,9 @@ void DerivedConformance::diagnoseIfSynthesisUnsupportedForDecl(
     shouldDiagnose = !isa<EnumDecl>(nominal);
   }
 
+  if (isa<BuiltinTupleDecl>(nominal))
+    shouldDiagnose = false;
+
   if (shouldDiagnose) {
     auto &ctx = nominal->getASTContext();
     ctx.Diags.diagnose(nominal->getLoc(),
diff --git a/test/Generics/tuple-conformances-synthesize-crash.swift b/test/Generics/tuple-conformances-synthesize-crash.swift
@@ -0,0 +1,5 @@
+// RUN: not %target-swift-frontend -typecheck %s
+
+// Just don't crash.
+extension () : Comparable {}
+

Original file line number	Diff line number	Diff line change
`@@ -272,6 +272,9 @@ void DerivedConformance::diagnoseIfSynthesisUnsupportedForDecl(`
`272`	`272`	`shouldDiagnose = !isa<EnumDecl>(nominal);`
`273`	`273`	`}`
`274`	`274`
	`275`	`+ if (isa<BuiltinTupleDecl>(nominal))`
	`276`	`+ shouldDiagnose = false;`
	`277`	`+`
`275`	`278`	`if (shouldDiagnose) {`
`276`	`279`	`auto &ctx = nominal->getASTContext();`
`277`	`280`	`ctx.Diags.diagnose(nominal->getLoc(),`