diff -r 82b1f8bc93a9 -r 0998a43cc155 src/compiler/CompileContext.h
--- a/src/compiler/CompileContext.h	Sat Dec 29 00:12:27 2012 -0800
+++ b/src/compiler/CompileContext.h	Sat Dec 29 00:55:38 2012 -0800
@@ -36,19 +36,38 @@
 struct TranslationUnit;
 class ImportStatement;
 
-struct TranslationUnit : public PoolObject
+struct CompileError
+{
+    CompileError()
+      : message(NULL)
+    {
+    }
+    CompileError(unsigned line, unsigned col, const char *message)
+      : line(line),
+        col(col),
+        message(message)
+    {
+    }
+
+    unsigned line;
+    unsigned col;
+    const char *message;
+};
+
+struct TranslationUnit
 {
     TranslationUnit()
       : tree_(NULL),
-        failed_(false),
         importScope_(NULL),
-        globalScope_(NULL)
+        globalScope_(NULL),
+        oom_(false),
+        dependencyFailed_(false)
     {
     }
+    ~TranslationUnit();
 
     ParseTree *tree_;
     const char *path_;
-    bool failed_;
     PoolList<TranslationUnit *> dependents_;
     ImportScope *importScope_;
     GlobalScope *globalScope_;
@@ -61,7 +80,9 @@
         return dependents_;
     }
     bool failed() const {
-        return failed_;
+        return errors_.length() ||
+               oom_ ||
+               dependencyFailed_;
     }
     void setImportScope(ImportScope *scope) {
         assert(!importScope_);
@@ -77,20 +98,38 @@
     GlobalScope *globalScope() const {
         return globalScope_;
     }
+
+    void setDependencyFailed() {
+        dependencyFailed_ = true;
+    }
+    void setOutOfMemory() {
+        oom_ = true;
+    }
+    void appendError(const char *report, unsigned line, unsigned col) {
+        oom_ |= errors_.append(CompileError(line, col, report));
+    }
+    const Vector<CompileError> *errors() {
+        return &errors_;
+    }
+
+  private:
+    bool oom_;
+    bool dependencyFailed_;
+    Vector<CompileError> errors_;
 };
 
 class CompileContext
 {
     Zone *zone_;
-    unsigned failures_;
     const char *file_;
     Vector<TranslationUnit *> units_;
     Vector<TranslationUnit *> unparsed_;
+    TranslationUnit *active_;
 
   private:
     char *loadSource(const char *file, size_t *length);
     bool parse(TranslationUnit *unit);
-    bool evaluateImports(TranslationUnit *unit);
+    void evaluateImports(TranslationUnit *unit);
     bool propagateFailure();
 
   public:
@@ -99,15 +138,28 @@
 
     bool addTranslationUnit(TranslationUnit *unit);
     bool compile();
+    void enter(TranslationUnit *unit);
+    void leave();
 
     void reportErrorVa(const SourcePosition &pos, Message msg, va_list ap);
     void reportError(const SourcePosition &pos, Message msg, ...);
+};
 
-    unsigned failures() const {
-        return failures_;
+class AutoEnterCompileContext
+{
+    CompileContext &cc_;
+
+  public:
+    AutoEnterCompileContext(CompileContext &cc, TranslationUnit *unit)
+      : cc_(cc)
+    {
+      cc_.enter(unit);
+    }
+    ~AutoEnterCompileContext() {
+      cc_.leave();
     }
 };
 
-}
+} // namespace ke
 
 #endif // _include_jitcraft_compile_context_h_