Add labels to tasks (#45)

vendor/honnef.co/go/tools/functions/concrete.go

@@ -0,0 +1,56 @@
+package functions
+
+import (
+	"go/token"
+	"go/types"
+
+	"honnef.co/go/tools/ssa"
+)
+
+func concreteReturnTypes(fn *ssa.Function) []*types.Tuple {
+	res := fn.Signature.Results()
+	if res == nil {
+		return nil
+	}
+	ifaces := make([]bool, res.Len())
+	any := false
+	for i := 0; i < res.Len(); i++ {
+		_, ifaces[i] = res.At(i).Type().Underlying().(*types.Interface)
+		any = any || ifaces[i]
+	}
+	if !any {
+		return []*types.Tuple{res}
+	}
+	var out []*types.Tuple
+	for _, block := range fn.Blocks {
+		if len(block.Instrs) == 0 {
+			continue
+		}
+		ret, ok := block.Instrs[len(block.Instrs)-1].(*ssa.Return)
+		if !ok {
+			continue
+		}
+		vars := make([]*types.Var, res.Len())
+		for i, v := range ret.Results {
+			var typ types.Type
+			if !ifaces[i] {
+				typ = res.At(i).Type()
+			} else if mi, ok := v.(*ssa.MakeInterface); ok {
+				// TODO(dh): if mi.X is a function call that returns
+				// an interface, call concreteReturnTypes on that
+				// function (or, really, go through Descriptions,
+				// avoid infinite recursion etc, just like nil error
+				// detection)
+
+				// TODO(dh): support Phi nodes
+				typ = mi.X.Type()
+			} else {
+				typ = res.At(i).Type()
+			}
+			vars[i] = types.NewParam(token.NoPos, nil, "", typ)
+		}
+		out = append(out, types.NewTuple(vars...))
+	}
+	// TODO(dh): deduplicate out
+	return out
+}