Auto merge of #19007 - MortimerGoro:const_codegen, r=emilio

Fix Const IDL value compilation errors in codegen

<!-- Please describe your changes on the following line: -->

I found that some const WebIDL values fail at rust compile time.

Example:

const long long TIMEOUT_IGNORED  = -1;

```
906 |     ConstantSpec { name: b"TIMEOUT_IGNORED\0", value: ConstantVal::DoubleVal(-1) }]
    |                                                                              ^^ expected f64, found integral variable
    |
    = note: expected type `f64`
               found type `{integer}`
```

I added a explicit cast to to fix the problem in conversions that may fail to compile.

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- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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1 files changed, 13 insertions, 3 deletions

diff --git a/components/script/dom/bindings/codegen/CodegenRust.py b/components/script/dom/bindings/codegen/CodegenRust.py
index 3251290f398..b7438e6be0a 100644
--- a/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/components/script/dom/bindings/codegen/CodegenRust.py
@@ -1198,12 +1198,12 @@ def convertConstIDLValueToJSVal(value):
     if tag == IDLType.Tags.uint32:
         return "ConstantVal::UintVal(%s)" % (value.value)
     if tag in [IDLType.Tags.int64, IDLType.Tags.uint64]:
-        return "ConstantVal::DoubleVal(%s)" % (value.value)
+        return "ConstantVal::DoubleVal(%s as f64)" % (value.value)
     if tag == IDLType.Tags.bool:
         return "ConstantVal::BoolVal(true)" if value.value else "ConstantVal::BoolVal(false)"
     if tag in [IDLType.Tags.unrestricted_float, IDLType.Tags.float,
                IDLType.Tags.unrestricted_double, IDLType.Tags.double]:
-        return "ConstantVal::DoubleVal(%s)" % (value.value)
+        return "ConstantVal::DoubleVal(%s as f64)" % (value.value)
     raise TypeError("Const value of unhandled type: " + value.type)
 
 
@@ -4077,7 +4077,17 @@ class CGConstant(CGThing):
     def define(self):
         name = self.constant.identifier.name
         value = convertConstIDLValueToRust(self.constant.value)
-        return "pub const %s: %s = %s;\n" % (name, builtinNames[self.constant.value.type.tag()], value)
+
+        tag = self.constant.value.type.tag()
+        const_type = builtinNames[self.constant.value.type.tag()]
+        # Finite<f32> or Finite<f64> cannot be used un a constant declaration.
+        # Remote the Finite type from restricted float and double tag declarations.
+        if tag == IDLType.Tags.float:
+            const_type = "f32"
+        elif tag == IDLType.Tags.double:
+            const_type = "f64"
+
+        return "pub const %s: %s = %s;\n" % (name, const_type, value)
 
 
 def getUnionTypeTemplateVars(type, descriptorProvider):