Add staticcheck tool

vendor/honnef.co/go/tools/quickfix/qf1007/qf1007.go

@@ -0,0 +1,92 @@
+package qf1007
+
+import (
+	"go/ast"
+	"go/token"
+
+	"honnef.co/go/tools/analysis/code"
+	"honnef.co/go/tools/analysis/edit"
+	"honnef.co/go/tools/analysis/lint"
+	"honnef.co/go/tools/analysis/report"
+	"honnef.co/go/tools/pattern"
+
+	"golang.org/x/tools/go/analysis"
+	"golang.org/x/tools/go/analysis/passes/inspect"
+)
+
+var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
+	Analyzer: &analysis.Analyzer{
+		Name:     "QF1007",
+		Run:      run,
+		Requires: []*analysis.Analyzer{inspect.Analyzer},
+	},
+	Doc: &lint.RawDocumentation{
+		Title: "Merge conditional assignment into variable declaration",
+		Before: `
+x := false
+if someCondition {
+    x = true
+}`,
+		After:    `x := someCondition`,
+		Since:    "2021.1",
+		Severity: lint.SeverityHint,
+	},
+})
+
+var Analyzer = SCAnalyzer.Analyzer
+
+var checkConditionalAssignmentQ = pattern.MustParse(`(AssignStmt x@(Object _) ":=" assign@(Builtin b@(Or "true" "false")))`)
+var checkConditionalAssignmentIfQ = pattern.MustParse(`(IfStmt nil cond [(AssignStmt x@(Object _) "=" (Builtin b@(Or "true" "false")))] nil)`)
+
+func run(pass *analysis.Pass) (any, error) {
+	fn := func(node ast.Node) {
+		var body *ast.BlockStmt
+		switch node := node.(type) {
+		case *ast.FuncDecl:
+			body = node.Body
+		case *ast.FuncLit:
+			body = node.Body
+		default:
+			panic("unreachable")
+		}
+		if body == nil {
+			return
+		}
+
+		stmts := body.List
+		if len(stmts) < 2 {
+			return
+		}
+		for i, first := range stmts[:len(stmts)-1] {
+			second := stmts[i+1]
+			m1, ok := code.Match(pass, checkConditionalAssignmentQ, first)
+			if !ok {
+				continue
+			}
+			m2, ok := code.Match(pass, checkConditionalAssignmentIfQ, second)
+			if !ok {
+				continue
+			}
+			if m1.State["x"] != m2.State["x"] {
+				continue
+			}
+			if m1.State["b"] == m2.State["b"] {
+				continue
+			}
+
+			v := m2.State["cond"].(ast.Expr)
+			if m1.State["b"] == "true" {
+				v = &ast.UnaryExpr{
+					Op: token.NOT,
+					X:  v,
+				}
+			}
+			report.Report(pass, first, "could merge conditional assignment into variable declaration",
+				report.Fixes(edit.Fix("Merge conditional assignment into variable declaration",
+					edit.ReplaceWithNode(pass.Fset, m1.State["assign"].(ast.Node), v),
+					edit.Delete(second))))
+		}
+	}
+	code.Preorder(pass, fn, (*ast.FuncDecl)(nil), (*ast.FuncLit)(nil))
+	return nil, nil
+}