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Incorrect handling of token.{LEQ,GEQ} for constant-logical-expr #642

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Merged
chavacava merged 2 commits into from
Feb 27, 2022
Merged

Incorrect handling of token.{LEQ,GEQ} for constant-logical-expr #642

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fb0c9ef
fix: incorrect handling of token.{LEQ,GEQ} for constant-logical-expr …
shmsr Feb 26, 2022
a2456d8
tiny modification in comments
chavacava Feb 27, 2022
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18 changes: 15 additions & 3 deletions rule/constant-logical-expr.go
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Original file line number Diff line number Diff line change
@@ -1,9 +1,10 @@
package rule

import (
"github.com/mgechev/revive/lint"
"go/ast"
"go/token"

"github.com/mgechev/revive/lint"
)

// ConstantLogicalExprRule warns on constant logical expressions.
Expand Down Expand Up @@ -44,11 +45,13 @@ func (w *lintConstantLogicalExpr) Visit(node ast.Node) ast.Visitor {
return w
}

if n.Op == token.EQL {
// Handles cases like: a <= a, a == a, a >= a
if w.isEqualityOperator(n.Op) {
w.newFailure(n, "expression always evaluates to true")
return w
}

// Handles cases like: a < a, a > a, a != a
if w.isInequalityOperator(n.Op) {
w.newFailure(n, "expression always evaluates to false")
return w
Expand All @@ -69,9 +72,18 @@ func (w *lintConstantLogicalExpr) isOperatorWithLogicalResult(t token.Token) boo
return false
}

func (w *lintConstantLogicalExpr) isEqualityOperator(t token.Token) bool {
switch t {
case token.EQL, token.LEQ, token.GEQ:
return true
}

return false
}

func (w *lintConstantLogicalExpr) isInequalityOperator(t token.Token) bool {
switch t {
case token.LSS, token.GTR, token.NEQ, token.LEQ, token.GEQ:
case token.LSS, token.GTR, token.NEQ:
return true
}

Expand Down
6 changes: 4 additions & 2 deletions testdata/constant-logical-expr.go
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Original file line number Diff line number Diff line change
@@ -1,5 +1,7 @@
package fixtures

import "fmt"

// from github.com/ugorji/go/codec/helper.go
func isNaN(f float64) bool { return f != f } // MATCH /expression always evaluates to false/

Expand All @@ -9,9 +11,9 @@ func foo1(f float64) bool { return foo2(2.) > foo2(2.) } // MATCH /expression al

func foo2(f float64) bool { return f < f } // MATCH /expression always evaluates to false/

func foo3(f float64) bool { return f <= f } // MATCH /expression always evaluates to false/
func foo3(f float64) bool { return f <= f } // MATCH /expression always evaluates to true/

func foo4(f float64) bool { return f >= f } // MATCH /expression always evaluates to false/
func foo4(f float64) bool { return f >= f } // MATCH /expression always evaluates to true/

func foo5(f float64) bool { return f == f } // MATCH /expression always evaluates to true/

Expand Down