Coerce through dry-types' non-raising call

CHANGELOG.md

@@ -13,6 +13,7 @@
 * [#2918](https://github.com/ruby-grape/grape/pull/2918): Skip the dry-types round trip when a value already is the declared type - [@ericproulx](https://github.com/ericproulx).
 * [#2917](https://github.com/ruby-grape/grape/pull/2917): Read path captures out of the router's union match instead of re-running the route's pattern - [@ericproulx](https://github.com/ericproulx).
 * [#2921](https://github.com/ruby-grape/grape/pull/2921): Pin the router's request-time isolation regressions through requests instead of its instance variables - [@ericproulx](https://github.com/ericproulx).
+* [#2930](https://github.com/ruby-grape/grape/pull/2930): Coerce through dry-types' non-raising call so a rejected value no longer builds a backtrace - [@ericproulx](https://github.com/ericproulx).
 * Your contribution here.
 
 ### 4.0.0 (2026-09-07)

lib/grape/validations/types/dry_type_coercer.rb

@@ -43,11 +43,18 @@ def initialize(type, strict: false)
         # Coerces the given value to a type which was specified during
         # initialization as a type argument.
         #
+        # Given a block, dry-types reports a value it cannot coerce by calling
+        # the block instead of raising. Raising is what cost: its CoercionError
+        # is re-raised with the backtrace of the error underneath, and building
+        # that backtrace as strings at request depth took about 25 µs for every
+        # rejected value -- every `types: [Integer, String]` param given a
+        # string, every 400 for a mistyped value.
+        #
         # @param val [Object]
         def call(val)
           return if val.nil?
 
-          @coercer[val]
+          @coercer.call(val) { InvalidValue.new }
         rescue Dry::Types::CoercionError
           InvalidValue.new
         end