cmd/compile/types2, go/types: add position for "have" in failed interface satisfaction

With this change, we shall now see:

    *myS does not implement S (wrong type for DoSomething method)
        have DoSomething() (string, error) at ./main.go:9:14
	want DoSomething() (int, error)

instead of previously:

    *myS does not implement S (wrong type for DoSomething method)
        have DoSomething() (string, error)
	want DoSomething() (int, error)

Fixes #42841
Fixes #45813

Change-Id: I66990929e39b0d36f2e91da0d92f60586a9b84e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/373634
Trust: Robert Findley <rfindley@google.com>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

diff --git a/src/cmd/compile/internal/types2/lookup.go b/src/cmd/compile/internal/types2/lookup.go
index 5428b667a50400242de0a63c4b36261ddb2c33ad..2b710040a48cb45410a3d1c239e45c3253833e5d 100644 (file)
--- a/src/cmd/compile/internal/types2/lookup.go
+++ b/src/cmd/compile/internal/types2/lookup.go
@@ -428,18 +428,18 @@ func (check *Checker) missingMethodReason(V, T Type, m, wrongType *Func) string
        if wrongType != nil {
                if Identical(m.typ, wrongType.typ) {
                        if m.Name() == wrongType.Name() {
-                               r = check.sprintf("(%s has pointer receiver)", mname)
+                               r = check.sprintf("(%s has pointer receiver) at %s", mname, wrongType.Pos())
                        } else {
-                               r = check.sprintf("(missing %s)\n\t\thave %s^^%s\n\t\twant %s^^%s",
-                                       mname, wrongType.Name(), wrongType.typ, m.Name(), m.typ)
+                               r = check.sprintf("(missing %s)\n\t\thave %s^^%s at %s\n\t\twant %s^^%s",
+                                       mname, wrongType.Name(), wrongType.typ, wrongType.Pos(), m.Name(), m.typ)
                        }
                } else {
                        if check.conf.CompilerErrorMessages {
-                               r = check.sprintf("(wrong type for %s)\n\t\thave %s^^%s\n\t\twant %s^^%s",
-                                       mname, wrongType.Name(), wrongType.typ, m.Name(), m.typ)
+                               r = check.sprintf("(wrong type for %s)\n\t\thave %s^^%s at %s\n\t\twant %s^^%s",
+                                       mname, wrongType.Name(), wrongType.typ, wrongType.Pos(), m.Name(), m.typ)
                        } else {
-                               r = check.sprintf("(wrong type for %s: have %s, want %s)",
-                                       mname, wrongType.typ, m.typ)
+                               r = check.sprintf("(wrong type for %s)\n\thave %s at %s\n\twant %s",
+                                       mname, wrongType.typ, wrongType.Pos(), m.typ)
                        }
                }
                // This is a hack to print the function type without the leading

diff --git a/src/cmd/compile/internal/types2/testdata/check/issues.src b/src/cmd/compile/internal/types2/testdata/check/issues.src
index f4b6199b82e53ed556b4daac2b6ee97cc9ff9ea8..868df46bd9ea31cf5b3cefb3244b9b4bbf428404 100644 (file)
--- a/src/cmd/compile/internal/types2/testdata/check/issues.src
+++ b/src/cmd/compile/internal/types2/testdata/check/issues.src
@@ -137,7 +137,7 @@ func issue10260() {
        T1{}.foo /* ERROR cannot call pointer method foo on T1 */ ()
        x.Foo /* ERROR "x.Foo undefined \(type I1 has no field or method Foo, but does have foo\)" */ ()
 
-       _ = i2. /* ERROR impossible type assertion: i2.\(\*T1\)\n\t\*T1 does not implement I2 \(wrong type for method foo: have func\(\), want func\(x int\)\) */ (*T1)
+       _ = i2. /* ERROR impossible type assertion: i2.\(\*T1\)\n\t\*T1 does not implement I2 \(wrong type for method foo\)\n\thave func\(\) at \w+.+\d+.\d+\n\twant func\(x int\) */ (*T1)
 
        i1 = i0 /* ERROR cannot use .* missing method foo */
        i1 = t0 /* ERROR cannot use .* missing method foo */

diff --git a/src/go/types/lookup.go b/src/go/types/lookup.go
index 598f61524771a0b8bbd6a4103c56d5cf1223f22f..b9c5048b5d32e66f9ec9cc617934e49e6a545191 100644 (file)
--- a/src/go/types/lookup.go
+++ b/src/go/types/lookup.go
@@ -400,20 +400,21 @@ func (check *Checker) missingMethodReason(V, T Type, m, wrongType *Func) string
                mname = "method " + m.Name()
        }
        if wrongType != nil {
+               pos := check.fset.Position(wrongType.Pos())
                if Identical(m.typ, wrongType.typ) {
                        if m.Name() == wrongType.Name() {
-                               r = check.sprintf("(%s has pointer receiver)", mname)
+                               r = check.sprintf("(%s has pointer receiver) at %s", mname, pos)
                        } else {
-                               r = check.sprintf("(missing %s)\n\t\thave %s^^%s\n\t\twant %s^^%s",
-                                       mname, wrongType.Name(), wrongType.typ, m.Name(), m.typ)
+                               r = check.sprintf("(missing %s)\n\t\thave %s^^%s at %s\n\t\twant %s^^%s",
+                                       mname, wrongType.Name(), wrongType.typ, pos, m.Name(), m.typ)
                        }
                } else {
                        if compilerErrorMessages {
-                               r = check.sprintf("(wrong type for %s)\n\t\thave %s^^%s\n\t\twant %s^^%s",
-                                       mname, wrongType.Name(), wrongType.typ, m.Name(), m.typ)
+                               r = check.sprintf("(wrong type for %s)\n\t\thave %s^^%s at %s\n\t\twant %s^^%s",
+                                       mname, wrongType.Name(), wrongType.typ, pos, m.Name(), m.typ)
                        } else {
-                               r = check.sprintf("(wrong type for %s: have %s, want %s)",
-                                       mname, wrongType.typ, m.typ)
+                               r = check.sprintf("(wrong type for %s)\n\thave %s at %s\nwant %s",
+                                       mname, wrongType.typ, pos, m.typ)
                        }
                }
                // This is a hack to print the function type without the leading

diff --git a/test/fixedbugs/issue48471.go b/test/fixedbugs/issue48471.go
index ba6245ab41dee2bc5bc36d78e40b5b2175df6798..8c5d3d4efafd1c2de49be814c76704fa232353eb 100644 (file)
--- a/test/fixedbugs/issue48471.go
+++ b/test/fixedbugs/issue48471.go
@@ -29,12 +29,12 @@ func g() {
        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 \(missing M method\)"
        i = I(new(T)) // ERROR "cannot convert new\(T\) \(.*type \*T\) to type I:\n\t\*T does not implement I \(missing M method\)"
-       i = new(T2)   // ERROR "cannot use new\(T2\) \(.*type \*T2\) as type I in assignment:\n\t\*T2 does not implement I \(missing M method\)\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 \(wrong type for M method\)\n\t\thave M\(string\)\n\t\twant M\(int\)"
+       i = new(T2)   // ERROR "cannot use new\(T2\) \(.*type \*T2\) as type I in assignment:\n\t\*T2 does not implement I \(missing M method\)\n\t\thave m\(int\) at \w+.+\d.\d+\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 \(wrong type for M method\)\n\t\thave M\(string\) at \w+.+\d.\d+\n\t\twant M\(int\)"
        i = T4{}      // ERROR "cannot use T4\{\} \(.*type T4\) as type I in assignment:\n\tT4 does not implement I \(M method has pointer receiver\)"
        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.(*T2)   // ERROR "impossible type assertion: i.\(\*T2\)\n\t\*T2 does not implement I \(missing M method\)\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 \(wrong type for M method\)\n\t\thave M\(string\)\n\t\twant M\(int\)"
+       _ = i.(*T2)   // ERROR "impossible type assertion: i.\(\*T2\)\n\t\*T2 does not implement I \(missing M method\)\n\t\thave m\(int\) at \w+.+\d.\d+\n\t\twant M\(int\)"
+       _ = i.(*T3)   // ERROR "impossible type assertion: i.\(\*T3\)\n\t\*T3 does not implement I \(wrong type for M method\)\n\t\thave M\(string\) at \w+.+\d.\d+\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"
        _ = i