Allow type assertions

Author: esimonov

README.md

@@ -1,6 +1,6 @@
 # ifshort
 [![Go Report Card](https://goreportcard.com/badge/github.com/esimonov/ifshort)](https://goreportcard.com/report/github.com/esimonov/ifshort)
-<a href='https://github.com/jpoles1/gopherbadger' target='_blank'>![gopherbadger-tag-do-not-edit](https://img.shields.io/badge/Go%20Coverage-96%25-brightgreen.svg?longCache=true&style=flat)</a>
+<a href='https://github.com/jpoles1/gopherbadger' target='_blank'>![gopherbadger-tag-do-not-edit](https://img.shields.io/badge/Go%20Coverage-97%25-brightgreen.svg?longCache=true&style=flat)</a>
 
 Go linter that checks if your code uses short syntax for `if`-statements whenever possible.
 

pkg/analyzer/analyzer.go

@@ -229,6 +229,8 @@ func (nom namedOccurrenceMap) checkExpression(candidate ast.Expr, ifPos token.Po
 		nom.checkExpression(v.High, ifPos)
 		nom.checkExpression(v.Low, ifPos)
 		nom.checkExpression(v.X, ifPos)
+	case *ast.TypeAssertExpr:
+		nom.checkExpression(v.X, ifPos)
 	case *ast.UnaryExpr:
 		nom.checkExpression(v.X, ifPos)
 	}

pkg/analyzer/occurrences.go

@@ -125,7 +125,7 @@ func (nom namedOccurrenceMap) addFromAssignment(pass *analysis.Pass, assignment
 			continue
 		}
 
-		if ident.Name == "_" || ident.Obj == nil || isAssignmentToPointer(ident.Obj.Decl) {
+		if ident.Name == "_" || ident.Obj == nil || isUnshortenableAssignment(ident.Obj.Decl) {
 			continue
 		}
 
@@ -144,7 +144,7 @@ func (nom namedOccurrenceMap) addFromAssignment(pass *analysis.Pass, assignment
 	}
 }
 
-func isAssignmentToPointer(decl interface{}) bool {
+func isUnshortenableAssignment(decl interface{}) bool {
 	assign, ok := decl.(*ast.AssignStmt)
 	if !ok {
 		return false

testdata/testdata.go

@@ -442,3 +442,15 @@ func notUsed_AssignmentToPointer_OK() {
 		return
 	}
 }
+
+func notUsed_TypeAssertion_OK() {
+	v := getValue()
+	if v == nil {
+		noOp1(v)
+	}
+
+	w, ok := v.(*dummyType)
+	if !ok {
+		noOp2(w)
+	}
+}