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https://github.com/golang/go
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8f19394b62
Based on https://golang.org/cl/284256 for go/types. Brings this code more in line with go/types. Adjusted various tests to match new error messages which generally are now better: for assignment errors, instead of a generic "cannot convert" we now say "cannot use" followed by a clearer reason as to why not. Major differences to go/types with respect to the changed files: - Some of the new code now returns error codes, but they are only used internally for now, and not reported with errors. - go/types does not "convert" untyped nil values to target types, but here we do. This is unchanged from how types2 handled this before this CL. Change-Id: If45336d7ee679ece100f6d9d9f291a6ea55004d8 Reviewed-on: https://go-review.googlesource.com/c/go/+/302757 Trust: Robert Griesemer <gri@golang.org> Reviewed-by: Robert Findley <rfindley@google.com>
75 lines
2.4 KiB
Go
75 lines
2.4 KiB
Go
// errorcheck
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// Copyright 2009 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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// Verify that illegal assignments with both explicit and implicit conversions of literals are detected.
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// Does not compile.
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package main
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import "unsafe"
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// explicit conversion of constants
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var x1 = string(1)
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var x2 string = string(1)
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var x3 = int(1.5) // ERROR "convert|truncate"
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var x4 int = int(1.5) // ERROR "convert|truncate"
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var x5 = "a" + string(1)
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var x6 = int(1e100) // ERROR "overflow|cannot convert"
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var x7 = float32(1e1000) // ERROR "overflow|cannot convert"
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// unsafe.Pointer can only convert to/from uintptr
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var _ = string(unsafe.Pointer(uintptr(65))) // ERROR "convert|conversion"
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var _ = float64(unsafe.Pointer(uintptr(65))) // ERROR "convert|conversion"
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var _ = int(unsafe.Pointer(uintptr(65))) // ERROR "convert|conversion"
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// implicit conversions merit scrutiny
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var s string
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var bad1 string = 1 // ERROR "conver|incompatible|invalid|cannot"
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var bad2 = s + 1 // ERROR "conver|incompatible|invalid|cannot"
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var bad3 = s + 'a' // ERROR "conver|incompatible|invalid|cannot"
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var bad4 = "a" + 1 // ERROR "literals|incompatible|convert|invalid"
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var bad5 = "a" + 'a' // ERROR "literals|incompatible|convert|invalid"
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var bad6 int = 1.5 // ERROR "convert|truncate"
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var bad7 int = 1e100 // ERROR "overflow|truncated to int|truncated"
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var bad8 float32 = 1e200 // ERROR "overflow"
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// but these implicit conversions are okay
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var good1 string = "a"
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var good2 int = 1.0
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var good3 int = 1e9
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var good4 float64 = 1e20
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// explicit conversion of string is okay
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var _ = []rune("abc")
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var _ = []byte("abc")
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// implicit is not
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var _ []int = "abc" // ERROR "cannot use|incompatible|invalid|cannot convert"
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var _ []byte = "abc" // ERROR "cannot use|incompatible|invalid|cannot convert"
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// named string is okay
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type Tstring string
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var ss Tstring = "abc"
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var _ = []rune(ss)
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var _ = []byte(ss)
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// implicit is still not
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var _ []rune = ss // ERROR "cannot use|incompatible|invalid"
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var _ []byte = ss // ERROR "cannot use|incompatible|invalid"
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// named slice is now ok
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type Trune []rune
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type Tbyte []byte
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var _ = Trune("abc") // ok
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var _ = Tbyte("abc") // ok
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// implicit is still not
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var _ Trune = "abc" // ERROR "cannot use|incompatible|invalid|cannot convert"
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var _ Tbyte = "abc" // ERROR "cannot use|incompatible|invalid|cannot convert"
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