Using stack traces to explain type inference:
miniblog.
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I really like languages that store their runtime stack on the heap, such as Smalltalk.
You can write code as if you have tail call optimisation, but you still have normal stack traces for debugging.
Are there any languages that display stack traces really well? Do you have a favourite?
Playing with Dr Racket today. It has some really cute highlighting for stack traces and symbol definitions.

