Merge pull request #77576 from tshortli/tbdgen-lazy-typecheck-bad-extension

SIL: Skip visiting bad extensions in SILSymbolVisitor

Author: tshortli

lib/SIL/IR/SILSymbolVisitor.cpp

@@ -735,6 +735,9 @@ class SILSymbolVisitorImpl : public ASTVisitor<SILSymbolVisitorImpl> {
 
   void visitExtensionDecl(ExtensionDecl *ED) {
     auto nominal = ED->getExtendedNominal();
+    if (!nominal)
+      return;
+
     if (canSkipNominal(nominal))
       return;
 

test/TBD/lazy-typecheck-bad-conformance.swift renamed to test/TBD/lazy-typecheck-errors.swift

@@ -8,3 +8,7 @@ public protocol P {
 // expected-error@+1 {{type 'S' does not conform to protocol 'P'}}
 public struct S: P {
 }
+
+extension DoesNotExist {
+  public func method() {}
+}