fix[parser]: Make duplicate built-in import exception consistent

Author: Sporarum

tests/functional/codegen/modules/test_stateless_functions.py

@@ -323,6 +323,16 @@ def test_reject_duplicate_imports(make_input_bundle):
         compiler.compile_code(contract_source, input_bundle=input_bundle)
 
 
+def test_reject_duplicate_builtin_imports(make_input_bundle):
+    contract_source = """
+import math
+import math as math2
+    """
+    input_bundle = make_input_bundle({"contract.vy": contract_source})
+    with pytest.raises(DuplicateImport):
+        compiler.compile_code(contract_source, input_bundle=input_bundle)
+
+
 def test_nested_module_access(get_contract, make_input_bundle):
     lib1 = """
 import lib2

vyper/semantics/analysis/imports.py

@@ -88,6 +88,7 @@ class ImportAnalyzer:
     seen: OrderedSet[vy_ast.Module]
     _compiler_inputs: dict[CompilerInput, vy_ast.Module]
     toplevel_module: vy_ast.Module
+    importedBuiltins: dict[str, vy_ast.VyperNode] = dict()
 
     def __init__(self, input_bundle: InputBundle, graph: _ImportGraph, module_ast: vy_ast.Module):
         self.input_bundle = input_bundle
@@ -187,6 +188,13 @@ def _load_import(
         self, node: vy_ast.VyperNode, level: int, module_str: str, alias: str
     ) -> tuple[CompilerInput, Any]:
         if _is_builtin(level, module_str):
+            if module_str in self.importedBuiltins:
+                previous_import_stmt = self.importedBuiltins[module_str]
+                raise DuplicateImport(
+                    f"{module_str} imported more than once!", previous_import_stmt, node
+                )
+
+            self.importedBuiltins[module_str] = node
             return _load_builtin_import(level, module_str)
 
         path = _import_to_path(level, module_str)