1 files changed, 120 insertions, 0 deletions
diff --git a/vendor/github.com/mgechev/revive/rule/var-declarations.go b/vendor/github.com/mgechev/revive/rule/var-declarations.go
new file mode 100644
index 0000000000..441132115e
--- /dev/null
+++ b/vendor/github.com/mgechev/revive/rule/var-declarations.go
@@ -0,0 +1,120 @@
+package rule
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"go/types"
+
+	"github.com/mgechev/revive/lint"
+)
+
+// VarDeclarationsRule lints given else constructs.
+type VarDeclarationsRule struct{}
+
+// Apply applies the rule to given file.
+func (r *VarDeclarationsRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
+	var failures []lint.Failure
+
+	fileAst := file.AST
+	walker := &lintVarDeclarations{
+		file:    file,
+		fileAst: fileAst,
+		onFailure: func(failure lint.Failure) {
+			failures = append(failures, failure)
+		},
+	}
+
+	file.Pkg.TypeCheck()
+	ast.Walk(walker, fileAst)
+
+	return failures
+}
+
+// Name returns the rule name.
+func (r *VarDeclarationsRule) Name() string {
+	return "var-declaration"
+}
+
+type lintVarDeclarations struct {
+	fileAst   *ast.File
+	file      *lint.File
+	lastGen   *ast.GenDecl
+	onFailure func(lint.Failure)
+}
+
+func (w *lintVarDeclarations) Visit(node ast.Node) ast.Visitor {
+	switch v := node.(type) {
+	case *ast.GenDecl:
+		if v.Tok != token.CONST && v.Tok != token.VAR {
+			return nil
+		}
+		w.lastGen = v
+		return w
+	case *ast.ValueSpec:
+		if w.lastGen.Tok == token.CONST {
+			return nil
+		}
+		if len(v.Names) > 1 || v.Type == nil || len(v.Values) == 0 {
+			return nil
+		}
+		rhs := v.Values[0]
+		// An underscore var appears in a common idiom for compile-time interface satisfaction,
+		// as in "var _ Interface = (*Concrete)(nil)".
+		if isIdent(v.Names[0], "_") {
+			return nil
+		}
+		// If the RHS is a zero value, suggest dropping it.
+		zero := false
+		if lit, ok := rhs.(*ast.BasicLit); ok {
+			zero = zeroLiteral[lit.Value]
+		} else if isIdent(rhs, "nil") {
+			zero = true
+		}
+		if zero {
+			w.onFailure(lint.Failure{
+				Confidence: 0.9,
+				Node:       rhs,
+				Category:   "zero-value",
+				Failure:    fmt.Sprintf("should drop = %s from declaration of var %s; it is the zero value", w.file.Render(rhs), v.Names[0]),
+			})
+			return nil
+		}
+		lhsTyp := w.file.Pkg.TypeOf(v.Type)
+		rhsTyp := w.file.Pkg.TypeOf(rhs)
+
+		if !validType(lhsTyp) || !validType(rhsTyp) {
+			// Type checking failed (often due to missing imports).
+			return nil
+		}
+
+		if !types.Identical(lhsTyp, rhsTyp) {
+			// Assignment to a different type is not redundant.
+			return nil
+		}
+
+		// The next three conditions are for suppressing the warning in situations
+		// where we were unable to typecheck.
+
+		// If the LHS type is an interface, don't warn, since it is probably a
+		// concrete type on the RHS. Note that our feeble lexical check here
+		// will only pick up interface{} and other literal interface types;
+		// that covers most of the cases we care to exclude right now.
+		if _, ok := v.Type.(*ast.InterfaceType); ok {
+			return nil
+		}
+		// If the RHS is an untyped const, only warn if the LHS type is its default type.
+		if defType, ok := w.file.IsUntypedConst(rhs); ok && !isIdent(v.Type, defType) {
+			return nil
+		}
+
+		w.onFailure(lint.Failure{
+			Category:   "type-inference",
+			Confidence: 0.8,
+			Node:       v.Type,
+			Failure:    fmt.Sprintf("should omit type %s from declaration of var %s; it will be inferred from the right-hand side", w.file.Render(v.Type), v.Names[0]),
+		})
+		return nil
+	}
+	return w
+}