bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/ide-diagnostics/src/handlers/mismatched_array_pat_len.rs')
-rw-r--r--crates/ide-diagnostics/src/handlers/mismatched_array_pat_len.rs114
1 files changed, 114 insertions, 0 deletions
diff --git a/crates/ide-diagnostics/src/handlers/mismatched_array_pat_len.rs b/crates/ide-diagnostics/src/handlers/mismatched_array_pat_len.rs
new file mode 100644
index 0000000000..8cae405c92
--- /dev/null
+++ b/crates/ide-diagnostics/src/handlers/mismatched_array_pat_len.rs
@@ -0,0 +1,114 @@
+use crate::{Diagnostic, DiagnosticCode, DiagnosticsContext};
+
+// Diagnostic: mismatched-array-pat-len
+//
+// This diagnostic is triggered when an array pattern's element count does not
+// match the array's declared length.
+pub(crate) fn mismatched_array_pat_len(
+ ctx: &DiagnosticsContext<'_, '_>,
+ d: &hir::MismatchedArrayPatLen,
+) -> Diagnostic {
+ let (code, message) = if d.has_rest {
+ (
+ "E0528",
+ format!(
+ "pattern requires at least {} element{} but array has {}",
+ d.found,
+ if d.found == 1 { "" } else { "s" },
+ d.expected,
+ ),
+ )
+ } else {
+ (
+ "E0527",
+ format!(
+ "pattern requires {} element{} but array has {}",
+ d.found,
+ if d.found == 1 { "" } else { "s" },
+ d.expected,
+ ),
+ )
+ };
+ Diagnostic::new_with_syntax_node_ptr(
+ ctx,
+ DiagnosticCode::RustcHardError(code),
+ message,
+ d.pat.map(Into::into),
+ )
+ .stable()
+}
+
+#[cfg(test)]
+mod tests {
+ use crate::tests::check_diagnostics;
+
+ #[test]
+ fn array_pattern_too_few_elements() {
+ check_diagnostics(
+ r#"
+fn f(arr: [i32; 3]) {
+ let [_a, _b] = arr;
+ //^^^^^^^^ error: pattern requires 2 elements but array has 3
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn array_pattern_too_many_elements() {
+ check_diagnostics(
+ r#"
+fn f(arr: [i32; 2]) {
+ let [_a, _b, _c] = arr;
+ //^^^^^^^^^^^^ error: pattern requires 3 elements but array has 2
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn array_pattern_with_rest_too_short() {
+ check_diagnostics(
+ r#"
+fn f(arr: [i32; 2]) {
+ let [_a, _b, _c, ..] = arr;
+ //^^^^^^^^^^^^^^^^ error: pattern requires at least 3 elements but array has 2
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn array_pattern_with_rest_ok() {
+ check_diagnostics(
+ r#"
+fn f(arr: [i32; 5]) {
+ let [_a, _b, ..] = arr;
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn array_pattern_exact_length_ok() {
+ check_diagnostics(
+ r#"
+fn f(arr: [i32; 3]) {
+ let [_a, _b, _c] = arr;
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn array_pattern_singular_element_uses_singular() {
+ check_diagnostics(
+ r#"
+fn f(arr: [i32; 3]) {
+ let [_a] = arr;
+ //^^^^ error: pattern requires 1 element but array has 3
+}
+"#,
+ );
+ }
+}