diff --git a/cli/src/cli_util.rs b/cli/src/cli_util.rs
index 4b71f5b7e..1d8383ff4 100644
--- a/cli/src/cli_util.rs
+++ b/cli/src/cli_util.rs
@@ -157,7 +157,7 @@ use crate::complete;
 use crate::config::config_from_environment;
 use crate::config::parse_config_args;
 use crate::config::CommandNameAndArgs;
-use crate::config::ConfigArg;
+use crate::config::ConfigArgKind;
 use crate::config::ConfigEnv;
 use crate::diff_util;
 use crate::diff_util::DiffFormat;
@@ -3113,7 +3113,7 @@ pub struct EarlyArgs {
 }
 
 impl EarlyArgs {
-    fn merged_config_args(&self, matches: &ArgMatches) -> Vec<ConfigArg> {
+    fn merged_config_args(&self, matches: &ArgMatches) -> Vec<(ConfigArgKind, &str)> {
         merge_args_with(
             matches,
             &[
@@ -3121,8 +3121,8 @@ impl EarlyArgs {
                 ("config_file", &self.config_file),
             ],
             |id, value| match id {
-                "config_toml" => ConfigArg::Toml(value.clone()),
-                "config_file" => ConfigArg::File(value.clone()),
+                "config_toml" => (ConfigArgKind::Toml, value.as_ref()),
+                "config_file" => (ConfigArgKind::File, value.as_ref()),
                 _ => unreachable!("unexpected id {id:?}"),
             },
         )
diff --git a/cli/src/config.rs b/cli/src/config.rs
index b85d6f171..8e3fe5101 100644
--- a/cli/src/config.rs
+++ b/cli/src/config.rs
@@ -458,29 +458,40 @@ fn env_overrides_layer() -> ConfigLayer {
     layer
 }
 
-/// Configuration source/data provided as command-line argument.
-#[derive(Clone, Debug, Eq, PartialEq)]
-pub enum ConfigArg {
+/// Configuration source/data type provided as command-line argument.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum ConfigArgKind {
     /// `--config-toml=TOML`
-    Toml(String),
+    Toml,
     /// `--config-file=PATH`
-    File(String),
+    File,
 }
 
 /// Parses `--config-toml` arguments.
-pub fn parse_config_args(toml_strs: &[ConfigArg]) -> Result<Vec<ConfigLayer>, ConfigLoadError> {
+pub fn parse_config_args(
+    toml_strs: &[(ConfigArgKind, &str)],
+) -> Result<Vec<ConfigLayer>, ConfigLoadError> {
     // It might look silly that a layer is constructed per argument, but
     // --config-toml argument can contain a full TOML document, and it makes
     // sense to preserve line numbers within the doc. If we add
     // --config=KEY=VALUE, multiple values might be loaded into one layer.
     let source = ConfigSource::CommandArg;
-    toml_strs
-        .iter()
-        .map(|arg| match arg {
-            ConfigArg::Toml(text) => ConfigLayer::parse(source, text),
-            ConfigArg::File(path) => ConfigLayer::load_from_file(source, path.into()),
-        })
-        .try_collect()
+    let mut layers = Vec::new();
+    for (kind, chunk) in &toml_strs.iter().chunk_by(|&(kind, _)| kind) {
+        match kind {
+            ConfigArgKind::Toml => {
+                for (_, text) in chunk {
+                    layers.push(ConfigLayer::parse(source, text)?);
+                }
+            }
+            ConfigArgKind::File => {
+                for (_, path) in chunk {
+                    layers.push(ConfigLayer::load_from_file(source, path.into())?);
+                }
+            }
+        }
+    }
+    Ok(layers)
 }
 
 /// Command name and arguments specified by config.