diff --git a/libsolidity/analysis/NameAndTypeResolver.cpp b/libsolidity/analysis/NameAndTypeResolver.cpp
index 53e008eb3..e639ba5e1 100644
--- a/libsolidity/analysis/NameAndTypeResolver.cpp
+++ b/libsolidity/analysis/NameAndTypeResolver.cpp
@@ -76,16 +76,8 @@ bool NameAndTypeResolver::performImports(SourceUnit& _sourceUnit, map<string, So
 		if (auto imp = dynamic_cast<ImportDirective const*>(node.get()))
 		{
 			string const& path = *imp->annotation().absolutePath;
-			if (!_sourceUnits.count(path))
-			{
-				m_errorReporter.declarationError(
-					5073_error,
-					imp->location(),
-					"Import \"" + path + "\" (referenced as \"" + imp->path() + "\") not found."
-				);
-				error = true;
-				continue;
-			}
+			// The import resolution in CompilerStack enforces this.
+			solAssert(_sourceUnits.count(path), "");
 			auto scope = m_scopes.find(_sourceUnits.at(path));
 			solAssert(scope != end(m_scopes), "");
 			if (!imp->symbolAliases().empty())
diff --git a/scripts/error_codes.py b/scripts/error_codes.py
index 1e88a2fd5..df6750a1f 100755
--- a/scripts/error_codes.py
+++ b/scripts/error_codes.py
@@ -223,7 +223,7 @@ def examine_id_coverage(top_dir, source_id_to_file_names, new_ids_only=False):
         "1584", "1823",
         "1988", "2066", "3356",
         "3893", "3996", "4010", "4802",
-        "5073", "5272", "5622", "7128",
+        "5272", "5622", "7128",
         "7589", "7593", "8065", "8084", "8140",
         "8312", "8592", "9085", "9609",
     }