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src/rules/suspicious/unit.bend checks

raw source on the hub · import 0xd96f2ab40f5df4925c42e96d0ba857ff/src/rules/suspicious/unit.bend as MUnit

rule unit: a multiply or divide by the literal one (1, 1n, 1.0) on a step that actually recurses. * and / inside (e : T) are T.mul and T.div; bare, they are Nat. Either form, and a direct Nat.mul / U32.mul / F32.mul or .div, does nothing when an operand is one (/ only when the divisor is). Drop the operation. Any other factor or divisor is left alone, and so is a base case or a def that does not call itself. A base case is a case arm that does not call the def; the arms are judged per case only, so a Bool.pick branch beside a self-call is still the recursive step, and so is a lambda body inside it (a Lazy.stop thunk or a List.map callback runs on the step). One finding per operation, on the literal: Nat.mul(1n, 1n) is one. Laws and proofs do not run (a def with no type at all fills a law: it is a proof).

7 imports
import Base
import ../../src.bend as Src
import ../../finding.bend as F
import ../../syntax/lex.bend as Lex
import ../../syntax/tree.bend as Tree
import ../calls.bend as Calls
import ../../lazy/lazy.bend as Lazy

Definitions

def one_text source · line 22 · raw

@+tt:String -> Bool

is the text the literal one?

def num_kind source · line 26 · raw

@kk:0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.TokKind -> Bool

is the kind a number token?

def one_tok source · line 34 · raw

@tok:0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok -> Bool

a token that is the literal one

def op_kind source · line 39 · raw

@kk:0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.TokKind -> Bool

is the kind an operator's?

def one_of source · line 47 · raw

@mm:Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok> -> Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok>

the maybe, when it holds the literal one

def either source · line 55 · raw

@aa:Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok> -> @bb:Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok> -> Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok>

the first maybe when it holds a token, else the second

def which source · line 64 · raw

@+op:String -> @prev:Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok> -> @+nxt:Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok> -> Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok>

the literal an operator's finding points at: for * the factor after it when it is one, else the one before; for / the divisor when it is one

def cite source · line 70 · raw

@mm:Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok> -> @+path:String -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

a finding on that literal

def arg_one source · line 79 · raw

@aa:0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node -> Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok>

an argument that is exactly the literal one

def last_one source · line 87 · raw

@as:List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node> -> Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok>

the last argument, when it is the literal one

def any_one source · line 97 · raw

@as:List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node> -> Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok>

the last argument that is the literal one

def on_div_is source · line 106 · raw

@+div:Bool -> @+as:List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node> -> @+path:String -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

a divide's divisor, when the call is a divide

def on_div source · line 114 · raw

@+tt:String -> @+as:List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node> -> @+path:String -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

a divide's divisor, when the call is a divide

def on_op_is source · line 118 · raw

@+mul:Bool -> @+tt:String -> @+as:List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node> -> @+path:String -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

a multiply (either factor) or a divide (the divisor only)

def on_op source · line 126 · raw

@+tt:String -> @+as:List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node> -> @+path:String -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

a multiply (either factor) or a divide (the divisor only)

def on_hot source · line 130 · raw

@hot:Bool -> @+tt:String -> @+as:List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node> -> @+path:String -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

the call's own identity operands, when this step recurses

def on_call source · line 138 · raw

@+tt:String -> @kids:0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node -> @+path:String -> @+hot:Bool -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

the call's own identity operands, when this step recurses

def own_of source · line 142 · raw

@call:Bool -> @+tt:String -> @+kids:0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node -> @+path:String -> @+hot:Bool -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

the call's findings when the group is an application

def first_tok source · line 156 · raw

@nn:0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node -> Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok>

the first leaf, when the chain starts with one

def after source · line 164 · raw

@tok:0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok -> Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok>

the token a leaf leaves behind for what follows it: none past an operator

def op_hit source · line 170 · raw

@tok:0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok -> @+prev:Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok> -> @+nxt:Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok> -> @+path:String -> @+hot:Bool -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

a leaf's own finding: an operator by one, in a hot region

def callee source · line 182 · raw

@mm:Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok> -> String

the name a group is called by: the token right before it ("" for none)

def walk source · line 192 · raw

@nn:0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/tree.Node -> @+prev:Maybe<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/syntax/lex.Tok> -> @+self:String -> @+path:String -> @+hot:Bool -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

* / / by one, and the same through calls, in a hot region. prev is the leaf right before, none past an operator, a group or a statement; a ( group right after a leaf is a call of it

def check.go source · line 214 · raw

@ds:List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/rules/calls.Def> -> @+path:String -> @acc:List<&2, List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>> -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

def check source · line 225 · raw

@ss:0xd96f2ab40f5df4925c42e96d0ba857ff/src/src.Src -> List<&2, 0xd96f2ab40f5df4925c42e96d0ba857ff/src/finding.Finding>

the rule