diff --git a/src/symboltable.rs b/src/symboltable.rs
index 10c13ba..8dc120e 100644
--- a/src/symboltable.rs
+++ b/src/symboltable.rs
@@ -1120,12 +1120,33 @@ impl SymbolTableBuilder {
             // Role already set..
             match role {
                 SymbolUsage::Global => {
-                    if !symbol.is_global() {
+                    if symbol.is_parameter {
+                        return Err(SymbolTableError {
+                            error: format!("name '{}' is parameter and global", name),
+                            location,
+                        });
+                    }
+                    if symbol.is_referenced {
                         return Err(SymbolTableError {
                             error: format!("name '{}' is used prior to global declaration", name),
                             location,
                         });
                     }
+                    if symbol.is_annotated {
+                        return Err(SymbolTableError {
+                            error: format!("annotated name '{}' can't be global", name),
+                            location,
+                        });
+                    }
+                    if symbol.is_assigned {
+                        return Err(SymbolTableError {
+                            error: format!(
+                                "name '{}' is assigned to before global declaration",
+                                name
+                            ),
+                            location,
+                        });
+                    }
                 }
                 SymbolUsage::Nonlocal => {
                     if symbol.is_parameter {