[backported/clang-7][Sema] Pop function scope when instantiating a func with skipped body

--------------------------------------------------------------------------
* Fixes a completion crash for which the test case was introduced with
  "[backported/clang-7][Sema] Don't skip function bodies with 'auto'
  without trailing return type" - so this makes tests pass again.
--------------------------------------------------------------------------

Summary:
By calling ActOnFinishFunctionBody(). Previously we were only calling
ActOnSkippedFunctionBody, which didn't pop the function scope.
This causes a crash when running on our internal code. No test-case,
though, since I couldn't come up with a small example in reasonable
time.

The bug was introduced in r321174.

Reviewers: bkramer, sammccall, sepavloff, aaron.ballman

Reviewed By: sammccall, aaron.ballman

Subscribers: aaron.ballman, cfe-commits

Differential Revision: https://reviews.llvm.org/D44439

Change-Id: I45ddee589212ea4178462b1e0f9fd032ded6fdf7
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@327504 91177308-0d34-0410-b5e6-96231b3b80d8
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

1 files changed, 6 insertions, 6 deletions

diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 9163fbc6f7..85d484ecec 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -3957,8 +3957,10 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
                                          TemplateArgs))
       return;
 
+    StmtResult Body;
     if (PatternDecl->hasSkippedBody()) {
       ActOnSkippedFunctionBody(Function);
+      Body = nullptr;
     } else {
       if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Function)) {
         // If this is a constructor, instantiate the member initializers.
@@ -3974,16 +3976,14 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
       }
 
       // Instantiate the function body.
-      StmtResult Body = SubstStmt(Pattern, TemplateArgs);
+      Body = SubstStmt(Pattern, TemplateArgs);
 
       if (Body.isInvalid())
         Function->setInvalidDecl();
-
-      // FIXME: finishing the function body while in an expression evaluation
-      // context seems wrong. Investigate more.
-      ActOnFinishFunctionBody(Function, Body.get(),
-                              /*IsInstantiation=*/true);
     }
+    // FIXME: finishing the function body while in an expression evaluation
+    // context seems wrong. Investigate more.
+    ActOnFinishFunctionBody(Function, Body.get(), /*IsInstantiation=*/true);
 
     PerformDependentDiagnostics(PatternDecl, TemplateArgs);