Solver fails to find redundancy

[FreeCAD-Bug-Importer]

Issue imported from https://tracker.freecad.org/view.php?id=3791

• Reporter: chrisb
• Date submitted: 1/24/2019
• FreeCAD version: 0.18
• Category: General
• Status: assigned
• Tags:

Original report text

Forum discussion.

Other bug information

• Priority: normal
• Severity: minor
• Category: General
• Updated: 2/6/2021

Discussion from Mantis ticket

Comment by bejant 2019-09-11 15:48

Here is another example of the Solver (in this example, DogLeg) failing to find redundancy.
https://forum.freecadweb.org/viewtopic.php?f=3&t=39233#p333307
File is attached to the first post of the forum topic.
Steps to reproduce:
Open Sketch and drag a vertical line segment a bit.
Apply a Horizontal Distance Constraint of 8 mm to the horizontal line segment.
Apply Tangency Constraints between the arc and the vertical line segments.
Delete whichever Vertical Constraint the Solver flags as redundant.
Result: 1 DOF remains (the horizontal lone segment can be moved vertically) but the Solver fails to detect that the Horizontal Distance Constraint of 8 mm is redundant.