// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Package ctrlflow is an analysis that provides a syntactic
// control-flow graph (CFG) for the body of a function.
// It records whether a function cannot return.
// By itself, it does not report any diagnostics.
package ctrlflow

import (
	"go/ast"
	"go/types"
	"log"
	"reflect"

	"golang.org/x/tools/go/analysis"

				cancelvars[v] = stmt
			}
		}
		return true
	})

	if len(cancelvars) == 0 {
		return // no need to inspect CFG
	}

	// Obtain the CFG.
	cfgs := pass.ResultOf[ctrlflow.Analyzer].(*ctrlflow.CFGs)
	var g *cfg.CFG
	var sig *types.Signature
	switch node := node.(type) {
	case *ast.FuncDecl:
		sig, _ = pass.TypesInfo.Defs[node.Name].Type().(*types.Signature)

driver runs the required analyzers first and makes their results
available in this map. Each Analyzer must return a value of the type
described in its Analyzer.ResultType field.
For example, the "ctrlflow" analyzer returns a *ctrlflow.CFGs, which
provides a control-flow graph for each function in the package (see
golang.org/x/tools/go/cfg); the "inspect" analyzer returns a value that

golang.org/x/tools/go/analysis/passes/buildtag
golang.org/x/tools/go/analysis/passes/cgocall
golang.org/x/tools/go/analysis/passes/composite
golang.org/x/tools/go/analysis/passes/copylock
golang.org/x/tools/go/analysis/passes/ctrlflow
golang.org/x/tools/go/analysis/passes/defers
golang.org/x/tools/go/analysis/passes/directive
golang.org/x/tools/go/analysis/passes/errorsas
golang.org/x/tools/go/analysis/passes/framepointer

// license that can be found in the LICENSE file.

// Package shift defines an Analyzer that checks for shifts that exceed
// the width of an integer.
package shift

// TODO(adonovan): integrate with ctrflow (CFG-based) dead code analysis. May
// have impedance mismatch due to its (non-)treatment of constant
// expressions (such as runtime.GOARCH=="386").

import (
	"go/ast"
	"go/constant"
	"go/token"
	"go/types"