RequirementMachine: Don't call getContextSubstitutionMap() on an existential type

slavapestov · slavapestov · commit 2adad14f7b11 · 2024-07-10T13:28:26.000-04:00
diff --git a/lib/AST/RequirementMachine/RequirementLowering.cpp b/lib/AST/RequirementMachine/RequirementLowering.cpp
@@ -637,7 +637,9 @@ struct InferRequirementsWalker : public TypeWalker {
       }
     }
 
-    if (!ty->isSpecialized())
+    // Both is<ExistentialType>() and isSpecialized() end up being true if we
+    // have invalid code where a protocol is nested inside a generic nominal.
+    if (ty->is<ExistentialType>() || !ty->isSpecialized())
       return Action::Continue;
 
     // Infer from generic nominal types.

Original file line number	Diff line number	Diff line change
`@@ -637,7 +637,9 @@ struct InferRequirementsWalker : public TypeWalker {`
`637`	`637`	`}`
`638`	`638`	`}`
`639`	`639`
`640`		`- if (!ty->isSpecialized())`
	`640`	`+ // Both is<ExistentialType>() and isSpecialized() end up being true if we`
	`641`	`+ // have invalid code where a protocol is nested inside a generic nominal.`
	`642`	`+ if (ty->is<ExistentialType>() \|\| !ty->isSpecialized())`
`641`	`643`	`return Action::Continue;`
`642`	`644`
`643`	`645`	`// Infer from generic nominal types.`