CMakeLists: Make variable shadowing a compile-time error

Now that the entire project is free of variable shadowing, we can enforce this as a compile time error to prevent any further introduction of this logic bug.

src/CMakeLists.txt

@@ -65,6 +65,10 @@ if (MSVC)
         /we4305 # 'context': truncation from 'type1' to 'type2'
         /we4388 # 'expression': signed/unsigned mismatch
         /we4389 # 'operator': signed/unsigned mismatch
+        /we4456 # Declaration of 'identifier' hides previous local declaration
+        /we4457 # Declaration of 'identifier' hides function parameter
+        /we4458 # Declaration of 'identifier' hides class member
+        /we4459 # Declaration of 'identifier' hides global declaration
         /we4505 # 'function': unreferenced local function has been removed
         /we4547 # 'operator': operator before comma has no effect; expected operator with side-effect
         /we4549 # 'operator1': operator before comma has no effect; did you intend 'operator2'?
@@ -92,6 +96,7 @@ else()
         -Werror=missing-declarations
         -Werror=missing-field-initializers
         -Werror=reorder
+        -Werror=shadow
         -Werror=sign-compare
         -Werror=switch
         -Werror=uninitialized

src/audio_core/CMakeLists.txt

@@ -49,9 +49,7 @@ if (NOT MSVC)
     target_compile_options(audio_core PRIVATE
         -Werror=conversion
         -Werror=ignored-qualifiers
-        -Werror=shadow
         -Werror=unused-parameter
-        -Werror=unused-variable
 
         $<$<CXX_COMPILER_ID:GNU>:-Werror=unused-but-set-parameter>
         $<$<CXX_COMPILER_ID:GNU>:-Werror=unused-but-set-variable>

src/core/CMakeLists.txt

@@ -743,16 +743,11 @@ if (MSVC)
         /we4244 # 'conversion': conversion from 'type1' to 'type2', possible loss of data
         /we4245 # 'conversion': conversion from 'type1' to 'type2', signed/unsigned mismatch
         /we4254 # 'operator': conversion from 'type1:field_bits' to 'type2:field_bits', possible loss of data
-        /we4456 # Declaration of 'identifier' hides previous local declaration
-        /we4457 # Declaration of 'identifier' hides function parameter
-        /we4458 # Declaration of 'identifier' hides class member
-        /we4459 # Declaration of 'identifier' hides global declaration
     )
 else()
     target_compile_options(core PRIVATE
         -Werror=conversion
         -Werror=ignored-qualifiers
-        -Werror=shadow
 
         $<$<CXX_COMPILER_ID:GNU>:-Werror=class-memaccess>
         $<$<CXX_COMPILER_ID:GNU>:-Werror=unused-but-set-parameter>

src/input_common/CMakeLists.txt

@@ -44,7 +44,6 @@ else()
         -Werror
         -Werror=conversion
         -Werror=ignored-qualifiers
-        -Werror=shadow
         $<$<CXX_COMPILER_ID:GNU>:-Werror=unused-but-set-parameter>
         $<$<CXX_COMPILER_ID:GNU>:-Werror=unused-but-set-variable>
         -Werror=unused-variable

src/shader_recompiler/CMakeLists.txt

@@ -253,9 +253,6 @@ else()
         -Werror
         -Werror=conversion
         -Werror=ignored-qualifiers
-        -Werror=implicit-fallthrough
-        -Werror=shadow
-        -Werror=sign-compare
         $<$<CXX_COMPILER_ID:GNU>:-Werror=unused-but-set-parameter>
         $<$<CXX_COMPILER_ID:GNU>:-Werror=unused-but-set-variable>
         -Werror=unused-variable

src/video_core/CMakeLists.txt

@@ -258,10 +258,6 @@ if (MSVC)
     target_compile_options(video_core PRIVATE
         /we4242 # 'identifier': conversion from 'type1' to 'type2', possible loss of data
         /we4244 # 'conversion': conversion from 'type1' to 'type2', possible loss of data
-        /we4456 # Declaration of 'identifier' hides previous local declaration
-        /we4457 # Declaration of 'identifier' hides function parameter
-        /we4458 # Declaration of 'identifier' hides class member
-        /we4459 # Declaration of 'identifier' hides global declaration
     )
 else()
     target_compile_options(video_core PRIVATE
@@ -269,7 +265,6 @@ else()
         -Wno-error=sign-conversion
         -Werror=pessimizing-move
         -Werror=redundant-move
-        -Werror=shadow
         -Werror=type-limits
 
         $<$<CXX_COMPILER_ID:GNU>:-Werror=class-memaccess>