As someone said, the best solution here is to use the dimensionality analysis in GNAT: https://docs.adacore.com/gnat_ugn-docs/html/gnat_ugn/gnat_ugn/gnat_and_pr

As someone said, the best solution here is to use the dimensionality analysis in GNAT: https://docs.adacore.com/gnat_ugn-docs/html/gnat_ugn/gnat_ugn/gnat_and_program_execution.html#performing-dimensionality-analysis-in-gnat https://docs.adacore.com/gnat_ugn-docs/html/gnat_ugn/gnat_ug... as in: with Ada.Text_IO; use Ada.Text_IO; with System.Dim.Float_Mks; use System.Dim.Float_Mks; with System.Dim.Float_Mks_IO; use System.Dim.Float_Mks_IO; procedure Main is subtype Distance is System.Dim.Float_Mks.Length; subtype Area is System.Dim.Float_Mks.Area; D1 : constant Distance := 10.0*m; D2 : constant Distance := 20.0*m; -- D3 : constant Distance := D1 * D2; -- Does not compile. GNAT returns the following error: -- main.adb:13:08: dimensions mismatch in object declaration -- main.adb:13:37: expected dimension [L], found [L**2] A : constant Area := D1 * D2; begin -- print: Area A is 2.00000E+02 m**2 Put ("Area A is "); Put (Item => A); Put_Line (""); end Main;