Fix interpolate typings definition (#1489)

* Fix interpolate definition

* Fix code generation due to build failure

* Remove unneeded code

Author: HarelM

build/generate-style-spec.ts

@@ -141,7 +141,7 @@ export type InterpolationSpecification =
     | ['linear'] 
     | ['exponential', number | ExpressionSpecification] 
     | ['cubic-bezier', number | ExpressionSpecification, number | ExpressionSpecification, number | ExpressionSpecification, number | ExpressionSpecification]
-    
+
 export type ExpressionSpecification = 
     // types
     | ['array', unknown | ExpressionSpecification] // array
@@ -196,8 +196,7 @@ export type ExpressionSpecification =
     | ['within', unknown | ExpressionSpecification]
     // Ramps, scales, curves
     | ['interpolate', InterpolationSpecification, 
-        number | ExpressionSpecification, number | ExpressionSpecification, ExpressionInputType | ExpressionSpecification, 
-        ...(number | ExpressionInputType | ExpressionSpecification)[]]
+        number | ExpressionSpecification, ...(number | ExpressionInputType | ExpressionSpecification)[]]
     | ['interpolate-hcl', InterpolationSpecification,
         number | ExpressionSpecification, number | ExpressionSpecification, ExpressionInputType | ExpressionSpecification, 
         ...(number | ColorSpecification | ExpressionSpecification)[]]

src/style-spec/feature_filter/feature_filter.test.ts

@@ -36,6 +36,13 @@ describe('filter', () => {
         compileTimeCheck(['match', ['get', 'TYPE'], ['TARGETPOINT:HOSPITAL'], true, false]);
         compileTimeCheck(['match', ['get', 'TYPE'], ['ADIZ', 'AMA', 'AWY', 'CLASS', 'NO-FIR', 'OCA', 'OTA', 'P', 'RAS', 'RCA', 'UTA', 'UTA-P'], true, false]);
         compileTimeCheck(['==', ['get', 'MILITARYAIRPORT'], 1]);
+        const colorStops = [0, 'red', 0.5, 'green', 1, 'blue'];
+        compileTimeCheck([
+            'interpolate',
+            ['linear'],
+            ['line-progress'],
+            ...colorStops
+        ]);
     });
 
     test('expression, zoom', () => {