mirror of
https://github.com/golang/go
synced 2024-11-18 21:34:46 -07:00
bc0b458b10
Fix type inference to expect a type name for the first "make()"
parameter and an integer for later parameters. For example:
// Previously we expected "[]int{}", now we expect "[]int".
var _ []int = make(<>)
Note that we don't currently support actually completing to unnamed
type names like "[]int", but this improvement at least eliminates
nonsensical completion suggestions.
// Previously we had no expectation, now we expect an int.
var _ []int = make([]int, <>)
Change-Id: Ifd349767662ab6902d3a3ea9e52de7df70cb37c7
Reviewed-on: https://go-review.googlesource.com/c/tools/+/217310
Run-TryBot: Muir Manders <muir@mnd.rs>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ingo Oeser <nightlyone@googlemail.com>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
114 lines
2.9 KiB
Go
114 lines
2.9 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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"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(obj types.Object, call *ast.CallExpr) objKind {
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astObj, err := c.snapshot.View().LookupBuiltin(c.ctx, obj.Name())
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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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decl, ok := astObj.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. "parentType" is the inferred type for the builtin call's
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// parent node.
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func (c *completer) builtinArgType(obj types.Object, call *ast.CallExpr, parentType types.Type) (infType types.Type, wantType, variadic bool) {
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exprIdx := exprAtPos(c.pos, call.Args)
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switch obj.Name() {
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case "append":
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// Check if we are completing the variadic append() param.
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variadic = exprIdx == 1 && len(call.Args) <= 2
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infType = parentType
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// If we are completing an individual element of the variadic
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// param, "deslice" the expected type.
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if !variadic && exprIdx > 0 {
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if slice, ok := parentType.(*types.Slice); ok {
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infType = slice.Elem()
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}
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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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infType = 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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infType = t1
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} else if exprIdx == 0 && t2 != nil {
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infType = t2
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}
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case "new":
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wantType = true
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if parentType != nil {
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// Expected type for "new" is the de-pointered parent type.
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if ptr, ok := parentType.Underlying().(*types.Pointer); ok {
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infType = 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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wantType = true
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infType = parentType
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} else {
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infType = types.Typ[types.Int]
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}
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}
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return infType, wantType, variadic
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}
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