QmlJS: Potentially fix hard-to-reproduce crash in JS completion.

* Context::build was potentially dangerous. Link and ScopeBuilder
  went out of scope before their results stopped being used.
* ScopeBuilder: If no function scope object was found, don't add it.

Reviewed-by: Erik Verbruggen

1 files changed, 2 insertions, 1 deletions

diff --git a/src/libs/qmljs/qmljsscopebuilder.cpp b/src/libs/qmljs/qmljsscopebuilder.cpp
index 80b3fbb7d7..2cc24a8cd5 100644
--- a/src/libs/qmljs/qmljsscopebuilder.cpp
+++ b/src/libs/qmljs/qmljsscopebuilder.cpp
@@ -33,7 +33,8 @@ void ScopeBuilder::push(AST::Node *node)
     // JS scopes
     if (FunctionDeclaration *fun = cast<FunctionDeclaration *>(node)) {
         ObjectValue *functionScope = _doc->bind()->findFunctionScope(fun);
-        _context->scopeChain().jsScopes += functionScope;
+        if (functionScope)
+            _context->scopeChain().jsScopes += functionScope;
     }
 
     _context->scopeChain().update();