cmd/compile: use "cannot use %s as %s value in %s: %s" error message

This is close to what the compiler used to say, except now we say
"as T value" rather than "as type T" which is closer to the truth
(we cannot use a value as a type, after all). Also, place the primary
error and the explanation (cause) on a single line.

Make respective (single line) adjustment to the matching "cannot
convert" error.

Adjust various tests.

For #55326.

Change-Id: Ib646cf906b11f4129b7ed0c38cf16471f9266b88
Reviewed-on: https://go-review.googlesource.com/c/go/+/436176
Reviewed-by: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

diff --git a/src/cmd/compile/internal/types2/assignments.go b/src/cmd/compile/internal/types2/assignments.go
index 2eca8238f9ad485843ab4506099e9aa738b9b070..e9cb62418e4f069d0c0f051ef19599d9afb78643 100644 (file)
--- a/src/cmd/compile/internal/types2/assignments.go
+++ b/src/cmd/compile/internal/types2/assignments.go
@@ -85,20 +85,12 @@ func (check *Checker) assignment(x *operand, T Type, context string) {
                return
        }
 
-       reason := ""
-       if ok, code := x.assignableTo(check, T, &reason); !ok {
-               if check.conf.CompilerErrorMessages {
-                       if reason != "" {
-                               check.errorf(x, code, "cannot use %s as type %s in %s:\n\t%s", x, T, context, reason)
-                       } else {
-                               check.errorf(x, code, "cannot use %s as type %s in %s", x, T, context)
-                       }
+       cause := ""
+       if ok, code := x.assignableTo(check, T, &cause); !ok {
+               if cause != "" {
+                       check.errorf(x, code, "cannot use %s as %s value in %s: %s", x, T, context, cause)
                } else {
-                       if reason != "" {
-                               check.errorf(x, code, "cannot use %s as %s value in %s: %s", x, T, context, reason)
-                       } else {
-                               check.errorf(x, code, "cannot use %s as %s value in %s", x, T, context)
-                       }
+                       check.errorf(x, code, "cannot use %s as %s value in %s", x, T, context)
                }
                x.mode = invalid
        }

diff --git a/src/cmd/compile/internal/types2/conversions.go b/src/cmd/compile/internal/types2/conversions.go
index 3b6a804335eda4d2272e920198d7f2670346d1e2..8c0607d608f07d0e8eaf2ffbceef3f1db269459a 100644 (file)
--- a/src/cmd/compile/internal/types2/conversions.go
+++ b/src/cmd/compile/internal/types2/conversions.go
@@ -70,15 +70,11 @@ func (check *Checker) conversion(x *operand, T Type) {
        }
 
        if !ok {
-               var err error_
-               err.code = _InvalidConversion
                if cause != "" {
-                       err.errorf(x, "cannot convert %s to type %s:", x, T)
-                       err.errorf(nopos, cause)
+                       check.errorf(x, _InvalidConversion, "cannot convert %s to type %s: %s", x, T, cause)
                } else {
-                       err.errorf(x, "cannot convert %s to type %s", x, T)
+                       check.errorf(x, _InvalidConversion, "cannot convert %s to type %s", x, T)
                }
-               check.report(&err)
                x.mode = invalid
                return
        }

diff --git a/src/go/types/assignments.go b/src/go/types/assignments.go
index 958d966e92b5bdc2ae85395294c0a3b27cd84187..15a12c69af38493779c678094225b97c75c7bdcf 100644 (file)
--- a/src/go/types/assignments.go
+++ b/src/go/types/assignments.go
@@ -84,20 +84,12 @@ func (check *Checker) assignment(x *operand, T Type, context string) {
                return
        }
 
-       reason := ""
-       if ok, code := x.assignableTo(check, T, &reason); !ok {
-               if compilerErrorMessages {
-                       if reason != "" {
-                               check.errorf(x, code, "cannot use %s as type %s in %s:\n\t%s", x, T, context, reason)
-                       } else {
-                               check.errorf(x, code, "cannot use %s as type %s in %s", x, T, context)
-                       }
+       cause := ""
+       if ok, code := x.assignableTo(check, T, &cause); !ok {
+               if cause != "" {
+                       check.errorf(x, code, "cannot use %s as %s value in %s: %s", x, T, context, cause)
                } else {
-                       if reason != "" {
-                               check.errorf(x, code, "cannot use %s as %s value in %s: %s", x, T, context, reason)
-                       } else {
-                               check.errorf(x, code, "cannot use %s as %s value in %s", x, T, context)
-                       }
+                       check.errorf(x, code, "cannot use %s as %s value in %s", x, T, context)
                }
                x.mode = invalid
        }

diff --git a/src/go/types/conversions.go b/src/go/types/conversions.go
index 43842a4132c0d133e195e0cecb8e24a9ea9592b6..ad88da90d7006152b9d9bbe2eeb0e65a54891fa2 100644 (file)
--- a/src/go/types/conversions.go
+++ b/src/go/types/conversions.go
@@ -8,7 +8,6 @@ package types
 
 import (
        "go/constant"
-       "go/token"
        "unicode"
 )
 
@@ -71,15 +70,11 @@ func (check *Checker) conversion(x *operand, T Type) {
        }
 
        if !ok {
-               var err error_
-               err.code = _InvalidConversion
                if cause != "" {
-                       err.errorf(x.Pos(), "cannot convert %s to type %s:", x, T)
-                       err.errorf(token.NoPos, cause)
+                       check.errorf(x, _InvalidConversion, "cannot convert %s to type %s: %s", x, T, cause)
                } else {
-                       err.errorf(x.Pos(), "cannot convert %s to type %s", x, T)
+                       check.errorf(x, _InvalidConversion, "cannot convert %s to type %s", x, T)
                }
-               check.report(&err)
                x.mode = invalid
                return
        }

diff --git a/src/internal/types/testdata/spec/conversions.go b/src/internal/types/testdata/spec/conversions.go
index 773f0917f271b6dad05b0213c310d98b7f0387b6..fc014fc2b0c5837305b360bd35a10fbe31b7804f 100644 (file)
--- a/src/internal/types/testdata/spec/conversions.go
+++ b/src/internal/types/testdata/spec/conversions.go
@@ -34,10 +34,10 @@ func _[
        T3 ~int | ~float64 | ~bool,
        T4 ~int | ~string,
 ]() {
-       _ = T1(0 /* ERROR cannot convert 0 .* to type T1:\n\tT1 does not contain specific types */)
-       _ = T2(1 /* ERROR cannot convert 1 .* to type T2:\n\tT2 does not contain specific types */)
-       _ = T3(2 /* ERROR cannot convert 2 .* to type T3:\n\tcannot convert 2 .* to type bool \(in T3\) */)
-       _ = T4(3.14 /* ERROR cannot convert 3.14 .* to type T4:\n\tcannot convert 3.14 .* to type int \(in T4\) */)
+       _ = T1(0 /* ERROR cannot convert 0 .* to type T1: T1 does not contain specific types */)
+       _ = T2(1 /* ERROR cannot convert 1 .* to type T2: T2 does not contain specific types */)
+       _ = T3(2 /* ERROR cannot convert 2 .* to type T3: cannot convert 2 .* to type bool \(in T3\) */)
+       _ = T4(3.14 /* ERROR cannot convert 3.14 .* to type T4: cannot convert 3.14 .* to type int \(in T4\) */)
 }
 
 // "x is assignable to T"
@@ -66,7 +66,7 @@ func _[X Foo, T Bar](x X) T       { return T(x) }
 func _[X Foo | Bar, T Bar](x X) T { return T(x) }
 func _[X Foo, T Foo | Bar](x X) T { return T(x) }
 func _[X Foo, T Far](x X) T {
-       return T(x /* ERROR cannot convert x \(variable of type X constrained by Foo\) to type T:\n\tcannot convert Foo \(in X\) to type Far \(in T\) */)
+       return T(x /* ERROR cannot convert x \(variable of type X constrained by Foo\) to type T: cannot convert Foo \(in X\) to type Far \(in T\) */)
 }
 
 // "x's type and T are unnamed pointer types and their pointer base types
@@ -76,7 +76,7 @@ func _[X ~*Foo, T ~*Bar](x X) T         { return T(x) }
 func _[X ~*Foo | ~*Bar, T ~*Bar](x X) T { return T(x) }
 func _[X ~*Foo, T ~*Foo | ~*Bar](x X) T { return T(x) }
 func _[X ~*Foo, T ~*Far](x X) T {
-       return T(x /* ERROR cannot convert x \(variable of type X constrained by ~\*Foo\) to type T:\n\tcannot convert \*Foo \(in X\) to type \*Far \(in T\) */)
+       return T(x /* ERROR cannot convert x \(variable of type X constrained by ~\*Foo\) to type T: cannot convert \*Foo \(in X\) to type \*Far \(in T\) */)
 }
 
 // Verify that the defined types in constraints are considered for the rule above.
@@ -109,14 +109,14 @@ func _[X Float, T Float](x X) T    { return T(x) }
 
 func _[X, T Integer | Unsigned | Float](x X) T { return T(x) }
 func _[X, T Integer | ~string](x X) T {
-       return T(x /* ERROR cannot convert x \(variable of type X constrained by Integer \| ~string\) to type T:\n\tcannot convert string \(in X\) to type int \(in T\) */)
+       return T(x /* ERROR cannot convert x \(variable of type X constrained by Integer \| ~string\) to type T: cannot convert string \(in X\) to type int \(in T\) */)
 }
 
 // "x's type and T are both complex types"
 
 func _[X, T Complex](x X) T { return T(x) }
 func _[X, T Float | Complex](x X) T {
-       return T(x /* ERROR cannot convert x \(variable of type X constrained by Float \| Complex\) to type T:\n\tcannot convert float32 \(in X\) to type complex64 \(in T\) */)
+       return T(x /* ERROR cannot convert x \(variable of type X constrained by Float \| Complex\) to type T: cannot convert float32 \(in X\) to type complex64 \(in T\) */)
 }
 
 // "x is an integer or a slice of bytes or runes and T is a string type"
@@ -129,7 +129,7 @@ func _[T ~string](x myInt) T    { return T(x) }
 func _[X Integer](x X) string   { return string(x) }
 func _[X Integer](x X) myString { return myString(x) }
 func _[X Integer](x X) *string {
-       return (*string)(x /* ERROR cannot convert x \(variable of type X constrained by Integer\) to type \*string:\n\tcannot convert int \(in X\) to type \*string */)
+       return (*string)(x /* ERROR cannot convert x \(variable of type X constrained by Integer\) to type \*string: cannot convert int \(in X\) to type \*string */)
 }
 
 func _[T ~string](x []byte) T                           { return T(x) }
@@ -138,7 +138,7 @@ func _[X ~[]byte, T ~string](x X) T                     { return T(x) }
 func _[X ~[]rune, T ~string](x X) T                     { return T(x) }
 func _[X Integer | ~[]byte | ~[]rune, T ~string](x X) T { return T(x) }
 func _[X Integer | ~[]byte | ~[]rune, T ~*string](x X) T {
-       return T(x /* ERROR cannot convert x \(variable of type X constrained by Integer \| ~\[\]byte \| ~\[\]rune\) to type T:\n\tcannot convert int \(in X\) to type \*string \(in T\) */)
+       return T(x /* ERROR cannot convert x \(variable of type X constrained by Integer \| ~\[\]byte \| ~\[\]rune\) to type T: cannot convert int \(in X\) to type \*string \(in T\) */)
 }
 
 // "x is a string and T is a slice of bytes or runes"
@@ -146,14 +146,14 @@ func _[X Integer | ~[]byte | ~[]rune, T ~*string](x X) T {
 func _[T ~[]byte](x string) T { return T(x) }
 func _[T ~[]rune](x string) T { return T(x) }
 func _[T ~[]rune](x *string) T {
-       return T(x /* ERROR cannot convert x \(variable of type \*string\) to type T:\n\tcannot convert \*string to type \[\]rune \(in T\) */)
+       return T(x /* ERROR cannot convert x \(variable of type \*string\) to type T: cannot convert \*string to type \[\]rune \(in T\) */)
 }
 
 func _[X ~string, T ~[]byte](x X) T           { return T(x) }
 func _[X ~string, T ~[]rune](x X) T           { return T(x) }
 func _[X ~string, T ~[]byte | ~[]rune](x X) T { return T(x) }
 func _[X ~*string, T ~[]byte | ~[]rune](x X) T {
-       return T(x /* ERROR cannot convert x \(variable of type X constrained by ~\*string\) to type T:\n\tcannot convert \*string \(in X\) to type \[\]byte \(in T\) */)
+       return T(x /* ERROR cannot convert x \(variable of type X constrained by ~\*string\) to type T: cannot convert \*string \(in X\) to type \[\]byte \(in T\) */)
 }
 
 // package unsafe:
@@ -164,7 +164,7 @@ type myUintptr uintptr
 func _[X ~uintptr](x X) unsafe.Pointer  { return unsafe.Pointer(x) }
 func _[T unsafe.Pointer](x myUintptr) T { return T(x) }
 func _[T unsafe.Pointer](x int64) T {
-       return T(x /* ERROR cannot convert x \(variable of type int64\) to type T:\n\tcannot convert int64 to type unsafe\.Pointer \(in T\) */)
+       return T(x /* ERROR cannot convert x \(variable of type int64\) to type T: cannot convert int64 to type unsafe\.Pointer \(in T\) */)
 }
 
 // "and vice versa"
@@ -173,7 +173,7 @@ func _[T ~uintptr](x unsafe.Pointer) T  { return T(x) }
 func _[X unsafe.Pointer](x X) uintptr   { return uintptr(x) }
 func _[X unsafe.Pointer](x X) myUintptr { return myUintptr(x) }
 func _[X unsafe.Pointer](x X) int64 {
-       return int64(x /* ERROR cannot convert x \(variable of type X constrained by unsafe\.Pointer\) to type int64:\n\tcannot convert unsafe\.Pointer \(in X\) to type int64 */)
+       return int64(x /* ERROR cannot convert x \(variable of type X constrained by unsafe\.Pointer\) to type int64: cannot convert unsafe\.Pointer \(in X\) to type int64 */)
 }
 
 // "x is a slice, T is an array or pointer-to-array type,

diff --git a/test/alias2.go b/test/alias2.go
index d7101420bdcafd2a054817ec017cecd59b343e94..2846e5dc31d21e8e455327eb789f9c202eb20053 100644 (file)
--- a/test/alias2.go
+++ b/test/alias2.go
@@ -46,8 +46,8 @@ var _ A0 = T0{}
 var _ T0 = A0{}
 
 // But aliases and original types cannot be used with new types based on them.
-var _ N0 = T0{} // ERROR "cannot use T0{} \(type T0\) as type N0 in assignment|cannot use T0{} \(value of type T0\) as type N0 in variable declaration"
-var _ N0 = A0{} // ERROR "cannot use T0{} \(type T0\) as type N0 in assignment|cannot use A0{} \(value of type T0\) as type N0 in variable declaration"
+var _ N0 = T0{} // ERROR "cannot use T0{} \(value of type T0\) as N0 value in variable declaration"
+var _ N0 = A0{} // ERROR "cannot use A0{} \(value of type T0\) as N0 value in variable declaration"
 
 var _ A5 = Value{}
 
@@ -82,10 +82,10 @@ func _() {
        var _ A0 = T0{}
        var _ T0 = A0{}
 
-       var _ N0 = T0{} // ERROR "cannot use T0{} \(type T0\) as type N0 in assignment|cannot use T0{} \(value of type T0\) as type N0 in variable declaration"
-       var _ N0 = A0{} // ERROR "cannot use T0{} \(type T0\) as type N0 in assignment|cannot use A0{} \(value of type T0\) as type N0 in variable declaration"
+       var _ N0 = T0{} // ERROR "cannot use T0{} \(value of type T0\) as N0 value in variable declaration"
+       var _ N0 = A0{} // ERROR "cannot use A0{} \(value of type T0\) as N0 value in variable declaration"
 
-       var _ A5 = Value{} // ERROR "cannot use reflect\.Value{} \(type reflect.Value\) as type A5 in assignment|cannot use Value{} \(value of type reflect.Value\) as type A5 in variable declaration"
+       var _ A5 = Value{} // ERROR "cannot use Value{} \(value of type reflect\.Value\) as A5 value in variable declaration"
 }
 
 // Invalid type alias declarations.

diff --git a/test/append1.go b/test/append1.go
index 397be570d99fd5d628b2b11aefa17a411a780d35..437e30ca236c0ffd960c03ed44d96095d68866a8 100644 (file)
--- a/test/append1.go
+++ b/test/append1.go
@@ -17,6 +17,6 @@ func main() {
        _ = append(s...)       // ERROR "cannot use ... on first argument|not enough arguments in call to append"
        _ = append(s, 2, s...) // ERROR "too many arguments to append|too many arguments in call to append"
 
-       _ = append(s, make([]int, 0))     // ERROR "cannot use make.* as type int in append|cannot use make.* \(value of type \[\]int\) as type int in argument to append"
+       _ = append(s, make([]int, 0))     // ERROR "cannot use make\(\[\]int, 0\) \(value of type \[\]int\) as int value in argument to append"
        _ = append(s, make([]int, -1)...) // ERROR "negative len argument in make|index -1.* must not be negative"
 }

diff --git a/test/ddd1.go b/test/ddd1.go
index 639b0bfdbdea8e220e33fd87c4c47ae5133c8d9b..e0035559867cf50ece064d0b8dc7ba9b2db90888 100644 (file)
--- a/test/ddd1.go
+++ b/test/ddd1.go
@@ -19,7 +19,7 @@ var (
        _ = sum(1.0, 2.0)
        _ = sum(1.5)      // ERROR "1\.5 .untyped float constant. as int|integer"
        _ = sum("hello")  // ERROR ".hello. (.untyped string constant. as int|.type untyped string. as type int)|incompatible"
-       _ = sum([]int{1}) // ERROR "\[\]int{.*}.*as type int"
+       _ = sum([]int{1}) // ERROR "\[\]int{.*}.*as int value"
 )
 
 func sum3(int, int, int) int { return 0 }

diff --git a/test/fixedbugs/bug389.go b/test/fixedbugs/bug389.go
index 209be8e6f7ace3b07ec8823396991203b4e7ff5b..3e8adb97285876ebdfb1056965aa3a2d99620f42 100644 (file)
--- a/test/fixedbugs/bug389.go
+++ b/test/fixedbugs/bug389.go
@@ -9,4 +9,4 @@ package foo
 
 func fn(a float32) {}
 
-var f func(arg int) = fn // ERROR "cannot use fn .type func.float32.. as type func.int. in assignment|different parameter types|cannot use fn .*type func.*float32.. as type func.*int. in variable declaration"
+var f func(arg int) = fn // ERROR "different parameter types|cannot use fn .*type func.*float32.. as func.*int. value in variable declaration"

diff --git a/test/fixedbugs/issue17645.go b/test/fixedbugs/issue17645.go
index 111fa81e136368c190ee3955267baa8a12829ce1..6eed5f1a38a04e644fd6e41e2512399dc277bcfe 100644 (file)
--- a/test/fixedbugs/issue17645.go
+++ b/test/fixedbugs/issue17645.go
@@ -12,5 +12,5 @@ type Foo struct {
 
 func main() {
        var s []int
-       var _ string = append(s, Foo{""}) // ERROR "cannot use .. \(.*untyped string.*\) as .*int.*|incompatible type" "cannot use Foo{.*} \(.*type Foo\) as type int in .*append" "cannot use append\(s\, Foo{.*}\) \(.*type \[\]int\) as type string in (assignment|variable declaration)"
+       var _ string = append(s, Foo{""}) // ERROR "cannot use append\(s, Foo{…}\) .* as string value in variable declaration" "cannot use Foo{…} .* as int value in argument to append" "cannot use .* as int value in struct literal"
 }

diff --git a/test/fixedbugs/issue48471.go b/test/fixedbugs/issue48471.go
index 8b8d64370aeee054b5179a55f9f44bbb87f53c4b..062cb5ab955fba2fd57524c4fa37172f851ff4a9 100644 (file)
--- a/test/fixedbugs/issue48471.go
+++ b/test/fixedbugs/issue48471.go
@@ -33,17 +33,17 @@ func (T6) m(int) string { return "" }
 func f(I)
 
 func g() {
-       f(new(T)) // ERROR "cannot use new\(T\) \(.*type \*T\) as type I in argument to f:\n\t\*T does not implement I \(missing method M\)"
+       f(new(T)) // ERROR "cannot use new\(T\) \(.*type \*T\) as I value in argument to f: \*T does not implement I \(missing method M\)"
 
        var i I
-       i = new(T)    // ERROR "cannot use new\(T\) \(.*type \*T\) as type I in assignment:\n\t\*T does not implement I \(missing method M\)"
-       i = I(new(T)) // ERROR "cannot convert new\(T\) \(.*type \*T\) to type I:\n\t\*T does not implement I \(missing method M\)"
-       i = new(T2)   // ERROR "cannot use new\(T2\) \(.*type \*T2\) as type I in assignment:\n\t\*T2 does not implement I \(missing method M\)\n\t\thave m\(int\)\n\t\twant M\(int\)"
+       i = new(T)    // ERROR "cannot use new\(T\) \(.*type \*T\) as I value in assignment: \*T does not implement I \(missing method M\)"
+       i = I(new(T)) // ERROR "cannot convert new\(T\) \(.*type \*T\) to type I: \*T does not implement I \(missing method M\)"
+       i = new(T2)   // ERROR "cannot use new\(T2\) \(.*type \*T2\) as I value in assignment: \*T2 does not implement I \(missing method M\)\n\t\thave m\(int\)\n\t\twant M\(int\)"
 
-       i = new(T3) // ERROR "cannot use new\(T3\) \(.*type \*T3\) as type I in assignment:\n\t\*T3 does not implement I \(wrong type for method M\)\n\t\thave M\(string\)\n\t\twant M\(int\)"
+       i = new(T3) // ERROR "cannot use new\(T3\) \(.*type \*T3\) as I value in assignment: \*T3 does not implement I \(wrong type for method M\)\n\t\thave M\(string\)\n\t\twant M\(int\)"
 
-       i = T4{}   // ERROR "cannot use T4\{\} \(.*type T4\) as type I in assignment:\n\tT4 does not implement I \(method M has pointer receiver\)"
-       i = new(I) // ERROR "cannot use new\(I\) \(.*type \*I\) as type I in assignment:\n\t\*I does not implement I \(type \*I is pointer to interface, not interface\)"
+       i = T4{}   // ERROR "cannot use T4\{\} \(.*type T4\) as I value in assignment: T4 does not implement I \(method M has pointer receiver\)"
+       i = new(I) // ERROR "cannot use new\(I\) \(.*type \*I\) as I value in assignment: \*I does not implement I \(type \*I is pointer to interface, not interface\)"
 
        _ = i.(*T2) // ERROR "impossible type assertion: i.\(\*T2\)\n\t\*T2 does not implement I \(missing method M\)\n\t\thave m\(int\)\n\t\twant M\(int\)"
        _ = i.(*T3) // ERROR "impossible type assertion: i.\(\*T3\)\n\t\*T3 does not implement I \(wrong type for method M\)\n\t\thave M\(string\)\n\t\twant M\(int\)"
@@ -51,6 +51,6 @@ func g() {
        _ = i.(T6)  // ERROR "impossible type assertion: i.\(T6\)\n\tT6 does not implement I \(missing method M\)\n\t\thave m\(int\) string\n\t\twant M\(int\)"
 
        var t *T4
-       t = i // ERROR "cannot use i \(variable of type I\) as type \*T4 in assignment:\n\tneed type assertion"
+       t = i // ERROR "cannot use i \(variable of type I\) as \*T4 value in assignment: need type assertion"
        _ = i
 }

diff --git a/test/fixedbugs/issue5358.go b/test/fixedbugs/issue5358.go
index 25f1e521fe8dde64398b172937eb458cae4b0cca..cfe8a9242a734748b08151a1ccae1759b1ee8fe7 100644 (file)
--- a/test/fixedbugs/issue5358.go
+++ b/test/fixedbugs/issue5358.go
@@ -13,5 +13,5 @@ func f(x int, y ...int) {}
 func g() (int, []int)
 
 func main() {
-       f(g()) // ERROR "as type int in|incompatible type"
+       f(g()) // ERROR "as int value in|incompatible type"
 }