cmd/vet: eliminate use of Perl in tests

This change uses errorCheck and wantedErrors functions copied from
the test/run.go to eliminate use of the test/errchk perl script.

Tests' error messages that contained full filenames were changed to
have base filenames because the errorCheck function processes output
from "go vet" in the same way.

Fixes #20032.

Change-Id: Ieb7be67c2d7281b9648171c698398449b7e2d4dd
Reviewed-on: https://go-review.googlesource.com/114176
Run-TryBot: Yury Smolsky <yury@smolsky.by>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

src/cmd/vet/testdata/atomic.go

@@ -43,7 +43,7 @@ func AtomicTests() {
 
 	{
 		// A variable declaration creates a new variable in the current scope.
-		x := atomic.AddUint64(&x, 1) // ERROR "declaration of .x. shadows declaration at testdata/atomic.go:16"
+		x := atomic.AddUint64(&x, 1) // ERROR "declaration of .x. shadows declaration at atomic.go:16"
 
 		// Re-declaration assigns a new value.
 		x, w := atomic.AddUint64(&x, 1), 10 // ERROR "direct assignment to atomic value"

src/cmd/vet/testdata/shadow.go

@@ -17,7 +17,7 @@ func ShadowRead(f *os.File, buf []byte) (err error) {
 		_ = err
 	}
 	if f != nil {
-		_, err := f.Read(buf) // ERROR "declaration of .err. shadows declaration at testdata/shadow.go:13"
+		_, err := f.Read(buf) // ERROR "declaration of .err. shadows declaration at shadow.go:13"
 		if err != nil {
 			return err
 		}
@@ -25,8 +25,8 @@ func ShadowRead(f *os.File, buf []byte) (err error) {
 		_ = i
 	}
 	if f != nil {
-		x := one()               // ERROR "declaration of .x. shadows declaration at testdata/shadow.go:14"
-		var _, err = f.Read(buf) // ERROR "declaration of .err. shadows declaration at testdata/shadow.go:13"
+		x := one()               // ERROR "declaration of .x. shadows declaration at shadow.go:14"
+		var _, err = f.Read(buf) // ERROR "declaration of .err. shadows declaration at shadow.go:13"
 		if x == 1 && err != nil {
 			return err
 		}
@@ -46,7 +46,7 @@ func ShadowRead(f *os.File, buf []byte) (err error) {
 	if shadowTemp := shadowTemp; true { // OK: obviously intentional idiomatic redeclaration
 		var f *os.File // OK because f is not mentioned later in the function.
 		// The declaration of x is a shadow because x is mentioned below.
-		var x int // ERROR "declaration of .x. shadows declaration at testdata/shadow.go:14"
+		var x int // ERROR "declaration of .x. shadows declaration at shadow.go:14"
 		_, _, _ = x, f, shadowTemp
 	}
 	// Use a couple of variables to trigger shadowing errors.

src/cmd/vet/testdata/structtag.go

@@ -44,40 +44,40 @@ type AnonymousXML struct{}
 
 type DuplicateJSONFields struct {
 	JSON              int `json:"a"`
-	DuplicateJSON     int `json:"a"` // ERROR "struct field DuplicateJSON repeats json tag .a. also at testdata/structtag.go:46"
+	DuplicateJSON     int `json:"a"` // ERROR "struct field DuplicateJSON repeats json tag .a. also at structtag.go:46"
 	IgnoredJSON       int `json:"-"`
 	OtherIgnoredJSON  int `json:"-"`
 	OmitJSON          int `json:",omitempty"`
 	OtherOmitJSON     int `json:",omitempty"`
-	DuplicateOmitJSON int `json:"a,omitempty"` // ERROR "struct field DuplicateOmitJSON repeats json tag .a. also at testdata/structtag.go:46"
+	DuplicateOmitJSON int `json:"a,omitempty"` // ERROR "struct field DuplicateOmitJSON repeats json tag .a. also at structtag.go:46"
 	NonJSON           int `foo:"a"`
 	DuplicateNonJSON  int `foo:"a"`
 	Embedded          struct {
 		DuplicateJSON int `json:"a"` // OK because its not in the same struct type
 	}
-	AnonymousJSON `json:"a"` // ERROR "struct field AnonymousJSON repeats json tag .a. also at testdata/structtag.go:46"
+	AnonymousJSON `json:"a"` // ERROR "struct field AnonymousJSON repeats json tag .a. also at structtag.go:46"
 
 	XML              int `xml:"a"`
-	DuplicateXML     int `xml:"a"` // ERROR "struct field DuplicateXML repeats xml tag .a. also at testdata/structtag.go:60"
+	DuplicateXML     int `xml:"a"` // ERROR "struct field DuplicateXML repeats xml tag .a. also at structtag.go:60"
 	IgnoredXML       int `xml:"-"`
 	OtherIgnoredXML  int `xml:"-"`
 	OmitXML          int `xml:",omitempty"`
 	OtherOmitXML     int `xml:",omitempty"`
-	DuplicateOmitXML int `xml:"a,omitempty"` // ERROR "struct field DuplicateOmitXML repeats xml tag .a. also at testdata/structtag.go:60"
+	DuplicateOmitXML int `xml:"a,omitempty"` // ERROR "struct field DuplicateOmitXML repeats xml tag .a. also at structtag.go:60"
 	NonXML           int `foo:"a"`
 	DuplicateNonXML  int `foo:"a"`
 	Embedded         struct {
 		DuplicateXML int `xml:"a"` // OK because its not in the same struct type
 	}
-	AnonymousXML `xml:"a"` // ERROR "struct field AnonymousXML repeats xml tag .a. also at testdata/structtag.go:60"
+	AnonymousXML `xml:"a"` // ERROR "struct field AnonymousXML repeats xml tag .a. also at structtag.go:60"
 	Attribute    struct {
 		XMLName     xml.Name `xml:"b"`
 		NoDup       int      `xml:"b"`                // OK because XMLName above affects enclosing struct.
 		Attr        int      `xml:"b,attr"`           // OK because <b b="0"><b>0</b></b> is valid.
-		DupAttr     int      `xml:"b,attr"`           // ERROR "struct field DupAttr repeats xml attribute tag .b. also at testdata/structtag.go:76"
-		DupOmitAttr int      `xml:"b,omitempty,attr"` // ERROR "struct field DupOmitAttr repeats xml attribute tag .b. also at testdata/structtag.go:76"
+		DupAttr     int      `xml:"b,attr"`           // ERROR "struct field DupAttr repeats xml attribute tag .b. also at structtag.go:76"
+		DupOmitAttr int      `xml:"b,omitempty,attr"` // ERROR "struct field DupOmitAttr repeats xml attribute tag .b. also at structtag.go:76"
 
-		AnonymousXML `xml:"b,attr"` // ERROR "struct field AnonymousXML repeats xml attribute tag .b. also at testdata/structtag.go:76"
+		AnonymousXML `xml:"b,attr"` // ERROR "struct field AnonymousXML repeats xml attribute tag .b. also at structtag.go:76"
 	}
 }