Remove invalid metric checks from formula operations

Because each metric is now its own type, these checks are redundant
and can be removed.

Signed-off-by: Sahas Subramanian <sahas.subramanian@proton.me>

Author: shsms

src/error.rs

@@ -58,7 +58,6 @@ ErrorKind!(
     (ChronoError, chrono_error),
     (DroppedUnusedFormulas, dropped_unused_formulas),
     (FormulaEngineError, formula_engine_error),
-    (InvalidMetric, invalid_metric),
     (Internal, internal)
 );
 

src/logical_meter/formula.rs

@@ -79,13 +79,6 @@ where
         let mut params_self: FormulaParams<T, M> = self.into();
         let params_other: FormulaParams<T, M> = other.into();
 
-        if params_self.metric != params_other.metric {
-            return Err(Error::invalid_metric(format!(
-                "Cannot coalesce formulas with different metrics: {} and {}",
-                params_self.metric.as_str_name(),
-                params_other.metric.as_str_name()
-            )));
-        }
         params_self.formula = params_self.formula.coalesce(params_other.formula);
         Ok(params_self.into())
     }
@@ -94,13 +87,6 @@ where
         let mut params_self: FormulaParams<T, M> = self.into();
         let params_other: FormulaParams<T, M> = other.into();
 
-        if params_self.metric != params_other.metric {
-            return Err(Error::invalid_metric(format!(
-                "Cannot take min of formulas with different metrics: {} and {}",
-                params_self.metric.as_str_name(),
-                params_other.metric.as_str_name()
-            )));
-        }
         params_self.formula = params_self.formula.min(params_other.formula);
         Ok(params_self.into())
     }
@@ -109,13 +95,6 @@ where
         let mut params_self: FormulaParams<T, M> = self.into();
         let params_other: FormulaParams<T, M> = other.into();
 
-        if params_self.metric != params_other.metric {
-            return Err(Error::invalid_metric(format!(
-                "Cannot take max of formulas with different metrics: {} and {}",
-                params_self.metric.as_str_name(),
-                params_other.metric.as_str_name()
-            )));
-        }
         params_self.formula = params_self.formula.max(params_other.formula);
         Ok(params_self.into())
     }

src/logical_meter/formula/aggregation_formula.rs

@@ -74,12 +74,6 @@ impl<M: Metric> std::ops::Add for AggregationFormula<M> {
     type Output = Result<Self, Error>;
 
     fn add(self, other: Self) -> Self::Output {
-        if self.metric != other.metric {
-            return Err(Error::invalid_metric(format!(
-                "Cannot add formulas with different metrics: {} and {}",
-                self.metric as isize, other.metric as isize
-            )));
-        }
         let new_formula = self.formula + other.formula;
         Ok(FormulaParams::new(new_formula, self.metric, self.instructions_tx).into())
     }
@@ -89,12 +83,6 @@ impl<M: Metric> std::ops::Sub for AggregationFormula<M> {
     type Output = Result<Self, Error>;
 
     fn sub(self, other: Self) -> Self::Output {
-        if self.metric != other.metric {
-            return Err(Error::invalid_metric(format!(
-                "Cannot subtract formulas with different metrics: {} and {}",
-                self.metric as isize, other.metric as isize
-            )));
-        }
         let new_formula = self.formula - other.formula;
         Ok(FormulaParams::new(new_formula, self.metric, self.instructions_tx).into())
     }