expr_type_mismatch

Expression argument’s type does not satisfy the function’s :params declaration.

Two failures share this code, and the message tells them apart.

The static one is the declared-type check: an argument whose type does not satisfy the head’s :params / :rest. It is anchored at the offending argument and names it by path (sqrt/0).

The runtime one fires when the types are fine but an evaluated value falls outside the function’s domain: (clamp 5 10 0) with lo above hi, (nth [1 2 3] 9) past the end, (normalize [0 0]) with no direction, (/ 1 0). The validator cannot reach these: it knows what a slot declares, not what an expression computes. They are anchored at the form’s head with no path, and the form yields no value while its neighbours keep evaluating.

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Run sjon explain expr_type_mismatch to read this at a terminal, browse every code, or work through diagnostics-driven repair if you want the habit rather than the answer.