[dev.typeparams] cmd/compile: port fix for issue46725 to transform.go

Allow fix for issue46725 to work for -G=3 mode.

Change-Id: Id522fbc2278cf878cb3f95b3205a2122c164ae29
Reviewed-on: https://go-review.googlesource.com/c/go/+/331470
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/internal/noder/transform.go

@@ -329,8 +329,20 @@ assignOK:
 		r.Use = ir.CallUseList
 		rtyp := r.Type()
 
+		mismatched := false
+		failed := false
 		for i := range lhs {
-			checkLHS(i, rtyp.Field(i).Type)
+			result := rtyp.Field(i).Type
+			checkLHS(i, result)
+
+			if lhs[i].Type() == nil || result == nil {
+				failed = true
+			} else if lhs[i] != ir.BlankNode && !types.Identical(lhs[i].Type(), result) {
+				mismatched = true
+			}
+		}
+		if mismatched && !failed {
+			typecheck.RewriteMultiValueCall(stmt, r)
 		}
 		return
 	}

src/cmd/compile/internal/typecheck/stmt.go

@@ -217,7 +217,7 @@ assignOK:
 			}
 		}
 		if mismatched && !failed {
-			rewriteMultiValueCall(stmt, r)
+			RewriteMultiValueCall(stmt, r)
 		}
 		return
 	}

src/cmd/compile/internal/typecheck/typecheck.go

@@ -962,12 +962,12 @@ func typecheckargs(n ir.InitNode) {
 	}
 
 	// Rewrite f(g()) into t1, t2, ... = g(); f(t1, t2, ...).
-	rewriteMultiValueCall(n, list[0])
+	RewriteMultiValueCall(n, list[0])
 }
 
-// rewriteMultiValueCall rewrites multi-valued f() to use temporaries,
+// RewriteMultiValueCall rewrites multi-valued f() to use temporaries,
 // so the backend wouldn't need to worry about tuple-valued expressions.
-func rewriteMultiValueCall(n ir.InitNode, call ir.Node) {
+func RewriteMultiValueCall(n ir.InitNode, call ir.Node) {
 	// If we're outside of function context, then this call will
 	// be executed during the generated init function. However,
 	// init.go hasn't yet created it. Instead, associate the

test/run.go

@@ -2131,7 +2131,6 @@ var excludedFiles = map[string]bool{
 	"fixedbugs/issue4232.go":   true, // types2 reports (correct) extra errors
 	"fixedbugs/issue4452.go":   true, // types2 reports (correct) extra errors
 	"fixedbugs/issue4510.go":   true, // types2 reports different (but ok) line numbers
-	"fixedbugs/issue46725.go":  true, // fix applied to typecheck needs to be ported to irgen/transform
 	"fixedbugs/issue5609.go":   true, // types2 needs a better error message
 	"fixedbugs/issue7525b.go":  true, // types2 reports init cycle error on different line - ok otherwise
 	"fixedbugs/issue7525c.go":  true, // types2 reports init cycle error on different line - ok otherwise