gopls/internal/lsp/source: abort change signature on overlapping calls

The heuristic used to identify remaining uninlined calls by counting
fails when the inlining operation changes the order of "original" calls,
as may be the case with overlapping calls, following CL 535456.

I spent around an hour trying to fix this properly (by tracking calls
that were "just" inlined), but it's too hard because we must also track
calls that had previously been inlined. It needs more theory and
thought. For now, remove support for overlapping calls, as in all other
cases the top-to-bottom counting heuristic should still work.

For golang/go#63534

Change-Id: I59fe4aa5d20e56b0eb9dcbc01d29dd2ece082c17
Reviewed-on: https://go-review.googlesource.com/c/tools/+/535795
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Alan Donovan <[email protected]>
Auto-Submit: Robert Findley <[email protected]>

Author: findleyr

gopls/internal/lsp/source/inline_all.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"go/ast"
 	"go/parser"
+	"go/types"
 
 	"golang.org/x/tools/go/ast/astutil"
 	"golang.org/x/tools/go/types/typeutil"
@@ -170,6 +171,17 @@ func inlineAllCalls(ctx context.Context, logf func(string, ...any), snapshot Sna
 			file    = callInfo.pgf.File
 			content = callInfo.pgf.Src
 		)
+
+		// Check for overlapping calls (such as Foo(Foo())). We can't handle these
+		// because inlining may change the source order of the inner call with
+		// respect to the inlined outer call, and so the heuristic we use to find
+		// the next call (counting from top-to-bottom) does not work.
+		for i := range calls {
+			if i > 0 && calls[i-1].End() > calls[i].Pos() {
+				return nil, fmt.Errorf("%s: can't inline overlapping call %s", uri, types.ExprString(calls[i-1]))
+			}
+		}
+
 		currentCall := 0
 		for currentCall < len(calls) {
 			caller := &inline.Caller{

gopls/internal/regtest/marker/testdata/codeaction/removeparam.txt

@@ -194,27 +194,15 @@ func h() (int, int)
 -- overlapping/overlapping.go --
 package overlapping
 
-func Overlapping(i int) int { //@codeaction("refactor.rewrite", re"(i) int", re"(i) int", overlapping)
+func Overlapping(i int) int { //@codeactionerr("refactor.rewrite", re"(i) int", re"(i) int", re"overlapping")
 	return 0
 }
 
 func _() {
 	x := Overlapping(Overlapping(0))
 	_ = x
 }
--- @overlapping/overlapping/overlapping.go --
-package overlapping
-
-func Overlapping() int { //@codeaction("refactor.rewrite", re"(i) int", re"(i) int", overlapping)
-	return 0
-}
 
-func _() {
-	x := func(_ int) int {
-		return Overlapping()
-	}(Overlapping())
-	_ = x
-}
 -- effects/effects.go --
 package effects