Import default expression of param before creating the param (#697)

Author: balazske

lib/AST/ASTImporter.cpp

@@ -3929,6 +3929,15 @@ ExpectedDecl ASTNodeImporter::VisitParmVarDecl(ParmVarDecl *D) {
   else
     return Imp.takeError();
 
+  Expr *DefaultArg = nullptr;
+  if (D->hasUninstantiatedDefaultArg()) {
+    if (Error Err = importInto(DefaultArg, D->getUninstantiatedDefaultArg()))
+      return std::move(Err);
+  } else if (D->hasDefaultArg()) {
+    if (Error Err = importInto(DefaultArg, D->getDefaultArg()))
+      return std::move(Err);
+  }
+
   ParmVarDecl *ToParm;
   if (GetImportedOrCreateDecl(ToParm, D, Importer.getToContext(), DC,
                               ToInnerLocStart, ToLocation,
@@ -3940,19 +3949,12 @@ ExpectedDecl ASTNodeImporter::VisitParmVarDecl(ParmVarDecl *D) {
   // Set the default argument.
   ToParm->setHasInheritedDefaultArg(D->hasInheritedDefaultArg());
   ToParm->setKNRPromoted(D->isKNRPromoted());
-
   if (D->hasUninstantiatedDefaultArg()) {
-    if (auto ToDefArgOrErr = import(D->getUninstantiatedDefaultArg()))
-      ToParm->setUninstantiatedDefaultArg(*ToDefArgOrErr);
-    else
-      return ToDefArgOrErr.takeError();
+    ToParm->setUninstantiatedDefaultArg(DefaultArg);
   } else if (D->hasUnparsedDefaultArg()) {
     ToParm->setUnparsedDefaultArg();
   } else if (D->hasDefaultArg()) {
-    if (auto ToDefArgOrErr = import(D->getDefaultArg()))
-      ToParm->setDefaultArg(*ToDefArgOrErr);
-    else
-      return ToDefArgOrErr.takeError();
+    ToParm->setDefaultArg(DefaultArg);
   }
 
   if (D->isObjCMethodParameter()) {

test/Analysis/Inputs/ctu-other.cpp

@@ -93,3 +93,22 @@ int other_macro_diag(int x) {
   MACRODIAG();
   return x;
 }
+
+struct DefParmContext {
+  static const int I;
+  int f();
+};
+
+int fDefParm(int I = DefParmContext::I) {
+  return I;
+}
+
+int testDefParmIncompleteImport(int I) {
+  return fDefParm(I);
+}
+
+const int DefParmContext::I = 0;
+
+int DefParmContext::f() {
+  return fDefParm();
+}

test/Analysis/Inputs/ctu-other.cpp.externalDefMap.txt

@@ -15,3 +15,4 @@ c:@N@chns@S@chcls@F@chf4#I# ctu-chain.cpp.ast
 c:@N@chns@F@chf2#I# ctu-chain.cpp.ast
 c:@F@fun_using_anon_struct#I# ctu-other.cpp.ast
 c:@F@other_macro_diag#I# ctu-other.cpp.ast
+c:@F@testDefParmIncompleteImport#I# ctu-other.cpp.ast

test/Analysis/ctu-main.cpp

@@ -75,6 +75,8 @@ void test_virtual_functions(mycls* obj) {
   clang_analyzer_eval(obj->fvcl(1) == 9);      // expected-warning{{FALSE}} expected-warning{{TRUE}}
 }
 
+extern int testDefParmIncompleteImport(int);
+
 int main() {
   clang_analyzer_eval(f(3) == 2); // expected-warning{{TRUE}}
   clang_analyzer_eval(f(4) == 3); // expected-warning{{TRUE}}
@@ -95,4 +97,6 @@ int main() {
   clang_analyzer_eval(other_macro_diag(1) == 1); // expected-warning{{TRUE}}
   // expected-warning@Inputs/ctu-other.cpp:93{{REACHABLE}}
   MACRODIAG(); // expected-warning{{REACHABLE}}
+
+  clang_analyzer_eval(testDefParmIncompleteImport(9) == 9); // expected-warning{{TRUE}}
 }