Fix defaults of BaseCompilerProperties

* Edition and Deny_warnings should not be set when
  constructing a BaseCompilerProperties, or the
  initialized values will reject values inherited from rust_defaults.
* Use getEdition and getDenyWarnings to retrieve those properties
  with defaults from config.

Bug: 141699953
Test: mm in rust projects
Change-Id: Id1ae357caeaf656cd33732bf4e54920e206f4ead

rust/compiler.go

@@ -20,14 +20,20 @@ import (
 
 	"android/soong/android"
 	"android/soong/rust/config"
+	"github.com/google/blueprint/proptools"
 )
 
+func getEdition(compiler *baseCompiler) string {
+	return proptools.StringDefault(compiler.Properties.Edition, config.DefaultEdition)
+}
+
+func getDenyWarnings(compiler *baseCompiler) bool {
+	return BoolDefault(compiler.Properties.Deny_warnings, config.DefaultDenyWarnings)
+}
+
 func NewBaseCompiler(dir, dir64 string) *baseCompiler {
 	return &baseCompiler{
-		Properties: BaseCompilerProperties{
-			Edition:       &config.DefaultEdition,
-			Deny_warnings: config.DefaultDenyWarnings,
-		},
+		Properties: BaseCompilerProperties{},
 		dir:        dir,
 		dir64:      dir64,
 	}
@@ -113,12 +119,12 @@ func (compiler *baseCompiler) featuresToFlags(features []string) []string {
 
 func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags) Flags {
 
-	if Bool(compiler.Properties.Deny_warnings) {
+	if getDenyWarnings(compiler) {
 		flags.RustFlags = append(flags.RustFlags, "-D warnings")
 	}
 	flags.RustFlags = append(flags.RustFlags, compiler.Properties.Flags...)
 	flags.RustFlags = append(flags.RustFlags, compiler.featuresToFlags(compiler.Properties.Features)...)
-	flags.RustFlags = append(flags.RustFlags, "--edition="+*compiler.Properties.Edition)
+	flags.RustFlags = append(flags.RustFlags, "--edition="+getEdition(compiler))
 	flags.LinkFlags = append(flags.LinkFlags, compiler.Properties.Ld_flags...)
 	flags.GlobalRustFlags = append(flags.GlobalRustFlags, config.GlobalRustFlags...)
 	flags.GlobalRustFlags = append(flags.GlobalRustFlags, ctx.toolchain().ToolchainRustFlags())

rust/config/global.go

@@ -17,8 +17,6 @@ package config
 import (
 	"strings"
 
-	"github.com/google/blueprint/proptools"
-
 	"android/soong/android"
 	_ "android/soong/cc/config"
 )
@@ -35,7 +33,7 @@ var (
 		"libtest",
 	}
 
-	DefaultDenyWarnings = proptools.BoolPtr(true)
+	DefaultDenyWarnings = true
 
 	GlobalRustFlags = []string{
 		"--remap-path-prefix $$(pwd)=",