mirror of
https://github.com/golang/go
synced 2024-11-18 16:24:42 -07:00
90696ccdc6
In the example:
append([]T{}, <>)
We used to track the "objType" as "[]T", and "variadicType" separately
as "T". However, most things are more interested in "T" vs "[]T", so
they had to fiddle around with swapping types. Now instead we track
objType as T, and add a "variadic=true" flag indicating that "[]T" is
also an acceptable type.
Change-Id: I8ee3ef840917378c8406368cb5c660a377498dfd
Reviewed-on: https://go-review.googlesource.com/c/tools/+/246698
Run-TryBot: Muir Manders <muir@mnd.rs>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
122 lines
3.0 KiB
Go
122 lines
3.0 KiB
Go
// Copyright 2020 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package source
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import (
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"context"
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"go/ast"
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"go/types"
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)
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// builtinArgKind determines the expected object kind for a builtin
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// argument. It attempts to use the AST hints from builtin.go where
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// possible.
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func (c *completer) builtinArgKind(ctx context.Context, obj types.Object, call *ast.CallExpr) objKind {
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builtin, err := c.snapshot.BuiltinPackage(ctx)
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if err != nil {
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return 0
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}
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exprIdx := exprAtPos(c.pos, call.Args)
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builtinObj := builtin.Package.Scope.Lookup(obj.Name())
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if builtinObj == nil {
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return 0
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}
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decl, ok := builtinObj.Decl.(*ast.FuncDecl)
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if !ok || exprIdx >= len(decl.Type.Params.List) {
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return 0
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}
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switch ptyp := decl.Type.Params.List[exprIdx].Type.(type) {
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case *ast.ChanType:
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return kindChan
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case *ast.ArrayType:
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return kindSlice
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case *ast.MapType:
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return kindMap
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case *ast.Ident:
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switch ptyp.Name {
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case "Type":
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switch obj.Name() {
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case "make":
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return kindChan | kindSlice | kindMap
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case "len":
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return kindSlice | kindMap | kindArray | kindString | kindChan
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case "cap":
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return kindSlice | kindArray | kindChan
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}
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}
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}
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return 0
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}
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// builtinArgType infers the type of an argument to a builtin
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// function. parentInf is the inferred type info for the builtin
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// call's parent node.
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func (c *completer) builtinArgType(obj types.Object, call *ast.CallExpr, parentInf candidateInference) candidateInference {
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var (
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exprIdx = exprAtPos(c.pos, call.Args)
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inf = candidateInference{}
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)
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switch obj.Name() {
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case "append":
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if parentInf.objType == nil {
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break
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}
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inf.objType = parentInf.objType
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if exprIdx > 0 {
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inf.objType = deslice(inf.objType)
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// Check if we are completing the variadic append() param.
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inf.variadic = exprIdx == 1 && len(call.Args) <= 2
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}
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case "delete":
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if exprIdx > 0 && len(call.Args) > 0 {
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// Try to fill in expected type of map key.
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firstArgType := c.pkg.GetTypesInfo().TypeOf(call.Args[0])
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if firstArgType != nil {
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if mt, ok := firstArgType.Underlying().(*types.Map); ok {
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inf.objType = mt.Key()
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}
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}
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}
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case "copy":
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var t1, t2 types.Type
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if len(call.Args) > 0 {
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t1 = c.pkg.GetTypesInfo().TypeOf(call.Args[0])
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if len(call.Args) > 1 {
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t2 = c.pkg.GetTypesInfo().TypeOf(call.Args[1])
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}
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}
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// Fill in expected type of either arg if the other is already present.
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if exprIdx == 1 && t1 != nil {
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inf.objType = t1
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} else if exprIdx == 0 && t2 != nil {
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inf.objType = t2
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}
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case "new":
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inf.typeName.wantTypeName = true
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if parentInf.objType != nil {
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// Expected type for "new" is the de-pointered parent type.
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if ptr, ok := parentInf.objType.Underlying().(*types.Pointer); ok {
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inf.objType = ptr.Elem()
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}
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}
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case "make":
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if exprIdx == 0 {
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inf.typeName.wantTypeName = true
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inf.objType = parentInf.objType
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} else {
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inf.objType = types.Typ[types.Int]
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}
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}
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return inf
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}
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