From: Robert Griesemer <gri@golang.org>
Date: Mon, 24 Feb 2025 22:47:30 +0000 (-0800)
Subject: go/types, types2: remove another coreType call in type checking range clause
X-Git-Tag: go1.25rc1~929
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=7194caf11b5b62778618ddb87e5adea5b04654bf;p=gostls13.git

go/types, types2: remove another coreType call in type checking range clause

For #70128.

Change-Id: I5949bccbfaaebc435ae8ac7c70580d9740de6f00
Reviewed-on: https://go-review.googlesource.com/c/go/+/652136
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
---

diff --git a/src/cmd/compile/internal/types2/stmt.go b/src/cmd/compile/internal/types2/stmt.go
index 3f5412fbdd..3cd29fbb4c 100644
--- a/src/cmd/compile/internal/types2/stmt.go
+++ b/src/cmd/compile/internal/types2/stmt.go
@@ -1040,10 +1040,15 @@ func rangeKeyVal(check *Checker, orig Type, allowVersion func(goVersion) bool) (
 		}
 		assert(typ.Recv() == nil)
 		// check iterator argument type
-		cb, _ := coreType(typ.Params().At(0).Type()).(*Signature)
+		var cause2 string
+		cb, _ := sharedUnder(check, typ.Params().At(0).Type(), &cause2).(*Signature)
 		switch {
 		case cb == nil:
-			return bad("func must be func(yield func(...) bool): argument is not func")
+			if cause2 != "" {
+				return bad(check.sprintf("func must be func(yield func(...) bool): in yield type, %s", cause2))
+			} else {
+				return bad("func must be func(yield func(...) bool): argument is not func")
+			}
 		case cb.Params().Len() > 2:
 			return bad("func must be func(yield func(...) bool): yield func has too many parameters")
 		case cb.Results().Len() != 1 || !Identical(cb.Results().At(0).Type(), universeBool):
diff --git a/src/go/types/stmt.go b/src/go/types/stmt.go
index 5426c5e719..983467e36a 100644
--- a/src/go/types/stmt.go
+++ b/src/go/types/stmt.go
@@ -1058,10 +1058,15 @@ func rangeKeyVal(check *Checker, orig Type, allowVersion func(goVersion) bool) (
 		}
 		assert(typ.Recv() == nil)
 		// check iterator argument type
-		cb, _ := coreType(typ.Params().At(0).Type()).(*Signature)
+		var cause2 string
+		cb, _ := sharedUnder(check, typ.Params().At(0).Type(), &cause2).(*Signature)
 		switch {
 		case cb == nil:
-			return bad("func must be func(yield func(...) bool): argument is not func")
+			if cause2 != "" {
+				return bad(check.sprintf("func must be func(yield func(...) bool): in yield type, %s", cause2))
+			} else {
+				return bad("func must be func(yield func(...) bool): argument is not func")
+			}
 		case cb.Params().Len() > 2:
 			return bad("func must be func(yield func(...) bool): yield func has too many parameters")
 		case cb.Results().Len() != 1 || !Identical(cb.Results().At(0).Type(), universeBool):
diff --git a/src/internal/types/testdata/spec/range.go b/src/internal/types/testdata/spec/range.go
index 26406fca8a..d77511ece0 100644
--- a/src/internal/types/testdata/spec/range.go
+++ b/src/internal/types/testdata/spec/range.go
@@ -164,6 +164,11 @@ func _[T ~func(func(int) bool)](x T) {
 	}
 }
 
+func _[T func() bool | func(int) bool]() {
+	for range func /* ERROR "func must be func(yield func(...) bool): in yield type, func() bool and func(int) bool have different underlying types" */ (T) {} {
+	}
+}
+
 // go.dev/issue/65236
 
 func seq0(func() bool) {}