go/types, types2: use 2nd operand position for comparison type mismatch errors

When a comparison is invalid due to mismatched types, we only know
when we see the 2nd operand; so use that operand's position for the
error message. This matches compiler behavior.

For #55326.

Change-Id: I79450756bbdd2b4bb90ed4e960a451be0197b186
Reviewed-on: https://go-review.googlesource.com/c/go/+/435555
Run-TryBot: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Reviewed-by: 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/expr.go b/src/cmd/compile/internal/types2/expr.go
index c700667034917fbf5abf5aceb4ed3dafbfababe3..1f27871c4262a92edead5e125ac82e03e7eac23a 100644 (file)
--- a/src/cmd/compile/internal/types2/expr.go
+++ b/src/cmd/compile/internal/types2/expr.go
@@ -788,11 +788,6 @@ func (check *Checker) comparison(x, y *operand, op syntax.Operator, switchCase b
                // know after seeing the 2nd operand whether we have
                // a type mismatch.
                errOp = y
-               // For now, if we're not running the compiler, use the
-               // position of x to minimize changes to existing tests.
-               if !check.conf.CompilerErrorMessages {
-                       errOp = x
-               }
                cause = check.sprintf("mismatched types %s and %s", x.typ, y.typ)
                goto Error
        }

diff --git a/src/go/types/expr.go b/src/go/types/expr.go
index ebb107b8c0e4118e7440b2164056ff08a6119ae2..06a0de7c3529873ba03cf070102d908c71ee23d0 100644 (file)
--- a/src/go/types/expr.go
+++ b/src/go/types/expr.go
@@ -765,11 +765,6 @@ func (check *Checker) comparison(x, y *operand, op token.Token, switchCase bool)
                // know after seeing the 2nd operand whether we have
                // a type mismatch.
                errOp = y
-               // For now, if we're not running the compiler, use the
-               // position of x to minimize changes to existing tests.
-               if !compilerErrorMessages {
-                       errOp = x
-               }
                cause = check.sprintf("mismatched types %s and %s", x.typ, y.typ)
                goto Error
        }

diff --git a/src/internal/types/testdata/check/const0.go b/src/internal/types/testdata/check/const0.go
index 229c248643dd748fe12e774d8d8df8919d368036..402e6cf5a95c321fdf1c79e5c9dd7ea63ee4cc1d 100644 (file)
--- a/src/internal/types/testdata/check/const0.go
+++ b/src/internal/types/testdata/check/const0.go
@@ -27,7 +27,7 @@ const (
        ub1 = true
        ub2 = 2 < 1
        ub3 = ui1 == uf1
-       ub4 = true /* ERROR "mismatched types untyped bool and untyped int" */ == 0
+       ub4 = true == 0 /* ERROR "mismatched types untyped bool and untyped int" */
 
        // integer values
        ui0 = 0
@@ -110,7 +110,7 @@ const (
        tb0 bool = false
        tb1 bool = true
        tb2 mybool = 2 < 1
-       tb3 mybool = ti1 /* ERROR "mismatched types" */ == tf1
+       tb3 mybool = ti1 == tf1 /* ERROR "mismatched types" */
 
        // integer values
        ti0 int8 = ui0

diff --git a/src/internal/types/testdata/check/expr2.go b/src/internal/types/testdata/check/expr2.go
index 6133dbb42bfeda72b062dd51c732e545801f2773..1cb65ad2a297fd41c7f238abd869c53b957f690b 100644 (file)
--- a/src/internal/types/testdata/check/expr2.go
+++ b/src/internal/types/testdata/check/expr2.go
@@ -10,7 +10,7 @@ func _bool() {
        const t = true == true
        const f = true == false
        _ = t /* ERROR cannot compare */ < f
-       _ = 0 /* ERROR mismatched types untyped int and untyped bool */ == t
+       _ = 0 == t /* ERROR mismatched types untyped int and untyped bool */
        var b bool
        var x, y float32
        b = x < y
@@ -29,7 +29,7 @@ func arrays() {
        _ = a == b
        _ = a != b
        _ = a /* ERROR < not defined */ < b
-       _ = a /* ERROR cannot compare.*mismatched types */ == nil
+       _ = a == nil /* ERROR cannot compare.*mismatched types */
 
        type C [10]int
        var c C
@@ -37,7 +37,7 @@ func arrays() {
 
        type D [10]int
        var d D
-       _ = c /* ERROR mismatched types */ == d
+       _ = c == d /* ERROR mismatched types */
 
        var e [10]func() int
        _ = e /* ERROR \[10\]func\(\) int cannot be compared */ == e
@@ -53,7 +53,7 @@ func structs() {
        _ = s == t
        _ = s != t
        _ = s /* ERROR < not defined */ < t
-       _ = s /* ERROR cannot compare.*mismatched types */ == nil
+       _ = s == nil /* ERROR cannot compare.*mismatched types */
 
        type S struct {
                x int
@@ -68,7 +68,7 @@ func structs() {
        var ss S
        var tt T
        _ = s == ss
-       _ = ss /* ERROR mismatched types */ == tt
+       _ = ss == tt /* ERROR mismatched types */
 
        var u struct {
                x int
@@ -115,11 +115,11 @@ func pointers() {
                p2 P2
        )
        _ = ps1 == ps1
-       _ = ps1 /* ERROR mismatched types */ == ps2
-       _ = ps2 /* ERROR mismatched types */ == ps1
+       _ = ps1 == ps2 /* ERROR mismatched types */
+       _ = ps2 == ps1 /* ERROR mismatched types */
 
        _ = p1 == p1
-       _ = p1 /* ERROR mismatched types */ == p2
+       _ = p1 == p2 /* ERROR mismatched types */
 
        _ = p1 == ps1
 }
@@ -147,13 +147,13 @@ func channels() {
                c2 C2
        )
        _ = c1 == c1
-       _ = c1 /* ERROR mismatched types */ == c1r
-       _ = c1 /* ERROR mismatched types */ == c1s
-       _ = c1r /* ERROR mismatched types */ == c1s
+       _ = c1 == c1r /* ERROR mismatched types */
+       _ = c1 == c1s /* ERROR mismatched types */
+       _ = c1r == c1s /* ERROR mismatched types */
        _ = c1 == c1a
        _ = c1a == c1
-       _ = c1 /* ERROR mismatched types */ == c2
-       _ = c1a /* ERROR mismatched types */ == c2
+       _ = c1 == c2 /* ERROR mismatched types */
+       _ = c1a == c2 /* ERROR mismatched types */
 
        // various element types (unnamed types)
        var (
@@ -166,11 +166,11 @@ func channels() {
        _ = d1 == d1
        _ = d1 == d1r
        _ = d1 == d1s
-       _ = d1r /* ERROR mismatched types */ == d1s
+       _ = d1r == d1s /* ERROR mismatched types */
        _ = d1 == d1a
        _ = d1a == d1
-       _ = d1 /* ERROR mismatched types */ == d2
-       _ = d1a /* ERROR mismatched types */ == d2
+       _ = d1 == d2 /* ERROR mismatched types */
+       _ = d1a == d2 /* ERROR mismatched types */
 }
 
 // for interfaces test
@@ -194,7 +194,7 @@ func interfaces() {
        var ii interface { m() int; n() }
        var k interface { m() float32 }
        _ = i == ii
-       _ = i /* ERROR mismatched types */ == k
+       _ = i == k /* ERROR mismatched types */
 
        // interfaces vs values
        var s1 S1
@@ -202,12 +202,12 @@ func interfaces() {
        var s2 S2
 
        _ = i == 0 /* ERROR cannot convert */
-       _ = i /* ERROR mismatched types */ == s1
+       _ = i == s1 /* ERROR mismatched types */
        _ = i == &s1
        _ = i == &s11
 
-       _ = i /* ERROR mismatched types */ == s2
-       _ = i /* ERROR mismatched types */ == &s2
+       _ = i == s2 /* ERROR mismatched types */
+       _ = i == & /* ERROR mismatched types */ s2
 
        // issue #28164
        // testcase from issue

diff --git a/src/internal/types/testdata/spec/comparisons.go b/src/internal/types/testdata/spec/comparisons.go
index 2a7598a5815d0f403ee07d17151fa0ef481f8a47..886e78c0a7aaa3d36434cff896c1aaeb598d8f10 100644 (file)
--- a/src/internal/types/testdata/spec/comparisons.go
+++ b/src/internal/types/testdata/spec/comparisons.go
@@ -40,10 +40,10 @@ func _() {
        _ = m /* ERROR map can only be compared to nil */ == m
        _ = c == c
 
-       _ = b /* ERROR mismatched types */ == nil
-       _ = a /* ERROR mismatched types */ == nil
+       _ = b == nil /* ERROR mismatched types */
+       _ = a == nil /* ERROR mismatched types */
        _ = l == nil
-       _ = s /* ERROR mismatched types */ == nil
+       _ = s == nil /* ERROR mismatched types */
        _ = p == nil
        _ = f == nil
        _ = i == nil
@@ -96,14 +96,14 @@ func _[
        _ = m /* ERROR incomparable types in type set */ == m
        _ = c == c
 
-       _ = b /* ERROR mismatched types */ == nil
-       _ = a /* ERROR mismatched types */ == nil
+       _ = b == nil /* ERROR mismatched types */
+       _ = a == nil /* ERROR mismatched types */
        _ = l == nil
-       _ = s /* ERROR mismatched types */ == nil
+       _ = s == nil /* ERROR mismatched types */
        _ = p == nil
        _ = f == nil
-       _ = i /* ERROR mismatched types */ == nil
-       _ = j /* ERROR mismatched types */ == nil
+       _ = i == nil /* ERROR mismatched types */
+       _ = j == nil /* ERROR mismatched types */
        _ = m == nil
        _ = c == nil