Handle nil end position in getMappedLocation (#1920)

Author: jakebailey

internal/ls/converters.go

@@ -166,6 +166,8 @@ func (c *Converters) LineAndCharacterToPosition(script Script, lineAndCharacter
 func (c *Converters) PositionToLineAndCharacter(script Script, position core.TextPos) lsproto.Position {
 	// UTF-8 offset to UTF-8/16 0-indexed line and character
 
+	position = min(position, core.TextPos(len(script.Text())))
+
 	lineMap := c.getLineMap(script.FileName())
 
 	line, isLineStart := slices.BinarySearch(lineMap.LineStarts, position)

internal/ls/source_map.go

@@ -18,6 +18,12 @@ func (l *LanguageService) getMappedLocation(fileName string, fileRange core.Text
 		}
 	}
 	endPos := l.tryGetSourcePosition(fileName, core.TextPos(fileRange.End()))
+	if endPos == nil {
+		endPos = &sourcemap.DocumentPosition{
+			FileName: startPos.FileName,
+			Pos:      startPos.Pos + fileRange.Len(),
+		}
+	}
 	debug.Assert(endPos.FileName == startPos.FileName, "start and end should be in same file")
 	newRange := core.NewTextRange(startPos.Pos, endPos.Pos)
 	lspRange := l.createLspRangeFromRange(newRange, l.getScript(startPos.FileName))