Merge pull request #12 from gostaticanalysis/fix-decl-stmt

Fix bug for valuespec

Author: tenntenn

forcetypeassert.go

@@ -24,38 +24,78 @@ func run(pass *analysis.Pass) (interface{}, error) {
 
 	nodeFilter := []ast.Node{
 		(*ast.AssignStmt)(nil),
+		(*ast.ValueSpec)(nil),
 	}
 
 	inspect.Preorder(nodeFilter, func(n ast.Node) {
 		switch n := n.(type) {
 		case *ast.AssignStmt:
-			if !hasTypeAssertion(n.Rhs) {
-				return
-			}
-			// if right hand has 2 or more values, assign statement can't assert boolean value which describes type assertion is succeeded
-			if len(n.Rhs) > 1 {
-				pass.Reportf(n.Pos(), "right hand must be only type assertion")
-				return
-			}
-			if len(n.Lhs) == 2 {
-				return
-			}
-
-			tae, ok := n.Rhs[0].(*ast.TypeAssertExpr)
-			if !ok {
-				pass.Reportf(n.Pos(), "right hand is not TypeAssertion")
-				return
-			}
-			if tae.Type == nil {
-				return
-			}
-			pass.Reportf(n.Pos(), "type assertion must be checked")
+			checkAssignStmt(pass, n)
+		case *ast.ValueSpec:
+			checkValueSpec(pass, n)
 		}
 	})
 
 	return nil, nil
 }
 
+func checkAssignStmt(pass *analysis.Pass, n *ast.AssignStmt) {
+	if !hasTypeAssertion(n.Rhs) {
+		return
+	}
+
+	// if right hand has 2 or more values, assign statement can't assert boolean value which describes type assertion is succeeded
+	if len(n.Rhs) > 1 {
+		pass.Reportf(n.Pos(), "right hand must be only type assertion")
+		return
+	}
+
+	if len(n.Lhs) == 2 {
+		return
+	}
+
+	tae, ok := n.Rhs[0].(*ast.TypeAssertExpr)
+	if !ok {
+		pass.Reportf(n.Pos(), "right hand is not TypeAssertion")
+		return
+	}
+
+	if tae.Type == nil {
+		return
+	}
+
+	pass.Reportf(n.Pos(), "type assertion must be checked")
+}
+
+func checkValueSpec(pass *analysis.Pass, n *ast.ValueSpec) {
+	if !hasTypeAssertion(n.Values) {
+		return
+	}
+
+	// if right hand has 2 or more values, assign statement can't assert boolean value which describes type assertion is succeeded
+	if len(n.Values) > 1 {
+		pass.Reportf(n.Pos(), "right hand must be only type assertion")
+		return
+	}
+
+	if len(n.Names) == 2 {
+		return
+	}
+
+	tae, ok := n.Values[0].(*ast.TypeAssertExpr)
+	if !ok {
+		pass.Reportf(n.Pos(), "right hand is not TypeAssertion")
+		return
+	}
+
+	if tae.Type == nil {
+		return
+	}
+
+	pass.Reportf(n.Pos(), "type assertion must be checked")
+
+}
+
 func hasTypeAssertion(exprs []ast.Expr) bool {
 	for _, node := range exprs {
 		_, ok := node.(*ast.TypeAssertExpr)

testdata/src/a/a.go

@@ -2,6 +2,10 @@ package a
 
 import "fmt"
 
+var _, _ = ((interface{})(nil)).(string)       // OK
+var _ = ((interface{})(nil)).(string)          // want `type assertion must be checked`
+var _, _ = ((interface{})(nil)).(string), true // want `right hand must be only type assertion`
+
 func f() {
 	var i interface{} = "hello"
 
@@ -24,4 +28,6 @@ func f() {
 	switch i.(type) { // ok
 	case string:
 	}
+
+	var _ = i.(string) // want `type assertion must be checked`
 }