diff --git a/lib/spack/spack/parser.py b/lib/spack/spack/parser.py
index 3416f2540b..6971368efc 100644
--- a/lib/spack/spack/parser.py
+++ b/lib/spack/spack/parser.py
@@ -288,9 +288,6 @@ def next_spec(
                     )
                     raise SpecParsingError(msg, self.ctx.current_token, self.literal_str)
 
-                if root_spec.concrete:
-                    raise spack.spec.RedundantSpecError(root_spec, "^" + str(dependency))
-
                 root_spec._add_dependency(dependency, deptypes=(), virtuals=())
 
             else:
@@ -306,13 +303,12 @@ def all_specs(self) -> List[spack.spec.Spec]:
 class SpecNodeParser:
     """Parse a single spec node from a stream of tokens"""
 
-    __slots__ = "ctx", "has_compiler", "has_version", "has_hash"
+    __slots__ = "ctx", "has_compiler", "has_version"
 
     def __init__(self, ctx):
         self.ctx = ctx
         self.has_compiler = False
         self.has_version = False
-        self.has_hash = False
 
     def parse(self, initial_spec: Optional[spack.spec.Spec] = None) -> Optional[spack.spec.Spec]:
         """Parse a single spec node from a stream of tokens
@@ -343,7 +339,6 @@ def parse(self, initial_spec: Optional[spack.spec.Spec] = None) -> Optional[spac
 
         while True:
             if self.ctx.accept(TokenType.COMPILER):
-                self.hash_not_parsed_or_raise(initial_spec, self.ctx.current_token.value)
                 if self.has_compiler:
                     raise spack.spec.DuplicateCompilerSpecError(
                         f"{initial_spec} cannot have multiple compilers"
@@ -353,7 +348,6 @@ def parse(self, initial_spec: Optional[spack.spec.Spec] = None) -> Optional[spac
                 initial_spec.compiler = spack.spec.CompilerSpec(compiler_name.strip(), ":")
                 self.has_compiler = True
             elif self.ctx.accept(TokenType.COMPILER_AND_VERSION):
-                self.hash_not_parsed_or_raise(initial_spec, self.ctx.current_token.value)
                 if self.has_compiler:
                     raise spack.spec.DuplicateCompilerSpecError(
                         f"{initial_spec} cannot have multiple compilers"
@@ -367,7 +361,6 @@ def parse(self, initial_spec: Optional[spack.spec.Spec] = None) -> Optional[spac
             elif self.ctx.accept(TokenType.VERSION) or self.ctx.accept(
                 TokenType.VERSION_HASH_PAIR
             ):
-                self.hash_not_parsed_or_raise(initial_spec, self.ctx.current_token.value)
                 if self.has_version:
                     raise spack.spec.MultipleVersionError(
                         f"{initial_spec} cannot have multiple versions"
@@ -378,25 +371,21 @@ def parse(self, initial_spec: Optional[spack.spec.Spec] = None) -> Optional[spac
                 initial_spec.attach_git_version_lookup()
                 self.has_version = True
             elif self.ctx.accept(TokenType.BOOL_VARIANT):
-                self.hash_not_parsed_or_raise(initial_spec, self.ctx.current_token.value)
                 variant_value = self.ctx.current_token.value[0] == "+"
                 initial_spec._add_flag(
                     self.ctx.current_token.value[1:].strip(), variant_value, propagate=False
                 )
             elif self.ctx.accept(TokenType.PROPAGATED_BOOL_VARIANT):
-                self.hash_not_parsed_or_raise(initial_spec, self.ctx.current_token.value)
                 variant_value = self.ctx.current_token.value[0:2] == "++"
                 initial_spec._add_flag(
                     self.ctx.current_token.value[2:].strip(), variant_value, propagate=True
                 )
             elif self.ctx.accept(TokenType.KEY_VALUE_PAIR):
-                self.hash_not_parsed_or_raise(initial_spec, self.ctx.current_token.value)
                 name, value = self.ctx.current_token.value.split("=", maxsplit=1)
                 name = name.strip("'\" ")
                 value = value.strip("'\" ")
                 initial_spec._add_flag(name, value, propagate=False)
             elif self.ctx.accept(TokenType.PROPAGATED_KEY_VALUE_PAIR):
-                self.hash_not_parsed_or_raise(initial_spec, self.ctx.current_token.value)
                 name, value = self.ctx.current_token.value.split("==", maxsplit=1)
                 name = name.strip("'\" ")
                 value = value.strip("'\" ")
@@ -411,12 +400,6 @@ def parse(self, initial_spec: Optional[spack.spec.Spec] = None) -> Optional[spac
 
         return initial_spec
 
-    def hash_not_parsed_or_raise(self, spec, addition):
-        if not self.has_hash:
-            return
-
-        raise spack.spec.RedundantSpecError(spec, addition)
-
 
 class FileParser:
     """Parse a single spec from a JSON or YAML file"""
diff --git a/lib/spack/spack/spec.py b/lib/spack/spack/spec.py
index 648cf55fae..bf06ca7aff 100644
--- a/lib/spack/spack/spec.py
+++ b/lib/spack/spack/spec.py
@@ -112,7 +112,6 @@
     "UnsatisfiableDependencySpecError",
     "AmbiguousHashError",
     "InvalidHashError",
-    "RedundantSpecError",
     "SpecDeprecatedError",
 ]
 
@@ -5331,14 +5330,6 @@ class NoSuchSpecFileError(SpecFilenameError):
     """Raised when a spec file doesn't exist."""
 
 
-class RedundantSpecError(spack.error.SpecError):
-    def __init__(self, spec, addition):
-        super().__init__(
-            "Attempting to add %s to spec %s which is already concrete."
-            " This is likely the result of adding to a spec specified by hash." % (addition, spec)
-        )
-
-
 class SpecFormatStringError(spack.error.SpecError):
     """Called for errors in Spec format strings."""