properly emit a warning for some cases of repeat in an array

src/check.rs

@@ -91,7 +91,7 @@ pub enum SigCheckErrorKind {
  Incorrect,
  Ambiguous,
  LoopOverreach,
- LoopExcess { sig: Signature, inf: bool },
+ LoopVariable { sig: Signature, inf: bool },
 }
 
 impl SigCheckError {
@@ -107,9 +107,9 @@ impl SigCheckError {
  ..self
  }
  }
- pub fn loop_excess(self, sig: Signature, inf: bool) -> Self {
+ pub fn loop_variable(self, sig: Signature, inf: bool) -> Self {
  Self {
- kind: SigCheckErrorKind::LoopExcess { sig, inf },
+ kind: SigCheckErrorKind::LoopVariable { sig, inf },
  ..self
  }
  }
@@ -405,7 +405,7 @@ impl<'a> VirtualEnv<'a> {
  return Err(SigCheckError::from(format!(
  "repeat with infinity and a function with signature {sig}"
  ))
- .loop_excess(sig, true));
+ .loop_variable(sig, true));
  }
  _ => self.handle_sig(sig)?,
  }
@@ -427,7 +427,7 @@ impl<'a> VirtualEnv<'a> {
  return Err(SigCheckError::from(format!(
  "repeat with no number and a function with signature {sig}"
  ))
- .loop_excess(sig, false));
+ .loop_variable(sig, false));
  }
  Ordering::Less => self.handle_sig(sig)?,
  }
@@ -450,7 +450,7 @@ impl<'a> VirtualEnv<'a> {
  return Err(SigCheckError::from(format!(
  "do with a function with signature {comp_sig}"
  ))
- .loop_excess(comp_sig, false));
+ .loop_variable(comp_sig, false));
  }
  self.handle_args_outputs(
  comp_sig.args,

src/compile/mod.rs

@@ -1310,12 +1310,43 @@ code:
  }
  Ok(())
  }
+ /// Emit a warning if a loop inside an array could
+ /// potentially pull in a variable number of values
  fn validate_array_loop_sig(&mut self, instrs: &[Instr], span: &CodeSpan) -> Option<Signature> {
  let inner_sig = instrs_signature(instrs);
  if self.current_bindings.is_empty() && self.scope.kind != ScopeKind::Temp {
  return inner_sig.ok();
  }
  let Err(e) = &inner_sig else {
+ // Case where repeat's function has a balanced signature
+ // This is fine in other contexts, so an error is not returned
+ // from the signature check, but it is not okay in an array.
+ if let Some(i) = instrs
+ .iter()
+ .position(|instr| matches!(instr, Instr::Prim(Primitive::Repeat, _)))
+ .filter(|&i| i > 0)
+ {
+ if let Instr::PushFunc(f) = &instrs[i - 1] {
+ let body_sig = f.signature();
+ let before_sig = instrs_signature(&instrs[..i - 1]).ok()?;
+ let after_sig = instrs_signature(&instrs[i + 1..]).ok()?;
+ if body_sig.args == body_sig.outputs
+ && before_sig.args < body_sig.args
+ && after_sig.args.saturating_sub(body_sig.outputs) < body_sig.args
+ {
+ let replacement: String =
+ repeat('⊙').take(body_sig.args).chain(['∘']).collect();
+ let message = format!(
+ "This array contains a loop with an equal number \
+ of arguments and outputs. This may result in a \
+ variable number of values being pulled into the \
+ array. To fix this, insert `{replacement}` on the \
+ right side of the array.",
+ );
+ self.emit_diagnostic(message, DiagnosticKind::Warning, span.clone());
+ }
+ }
+ }
  return inner_sig.ok();
  };
  let before_sig = (0..instrs.len())
@@ -1326,8 +1357,8 @@ code:
  .find_map(|i| instrs_signature(&instrs[i..]).ok())
  .unwrap();
  match e.kind {
- SigCheckErrorKind::LoopExcess { sig: body_sig, inf } => {
- let positive_body_sig = body_sig.outputs > body_sig.args;
+ SigCheckErrorKind::LoopVariable { sig: body_sig, inf } => {
+ let positive_body_sig = body_sig.outputs >= body_sig.args;
  let balanced_after_args = body_sig.args.saturating_sub(before_sig.outputs);
  if body_sig.args > 0
  && (positive_body_sig && after_sig.args != balanced_after_args && !inf)

tests/error.ua

@@ -41,6 +41,8 @@ F ← ⌊×10[◌◌⍥gen]⧻:0
 
 F ← [+⍥..]
 
+F ← {⍥∘}
+
 ⊕⊢ [0 2 2] [1 2 3]
 
 + ¤[1 2 3] [10_20_30_40 50_60_70_80]

todo.md

@@ -1,7 +1,6 @@
 # Uiua Todo
 
 - 0.12
- - Fix `{⍥∘}` not giving a warning
  - by inverses
  - `setinv` on and by inverses
  - Document on and by inverses